anechoic chambers a fundamental design and specification guide

5/19/2018 Anechoic Chambers a Fundamental Design and Specification Guide

http:///reader/full/anechoic-chambers-a-fundamental-design-and-specification-g

LECTROMAGNTCANECHOIC CHBERS



IEE Press

445 oes Lane, O ox 133Piscataway, J 08855-1331

IE ress ditoial Board

Samatios V Kaalopoulos,Editor in Chief

M Akay

J B Anderson

. J. Baker

. Bewer

M Eden

. E. Elawary

. J Herick

F oyt

D. Kirk

M S Newmn

M. Padge

W D. Reeve

G. Zbrist

Kenneth ooe, Director of IEEE PressCaherine Faduska, enior Acquisiions Edior

Christina Kuhnen, Associate Acquisitions Edior

IEEE Electomanetic Compatibi lity S ociety, ponsorEMC-S Liaison to IEEE Pess, Mark Monrose

IEEE Antennas and Popaation Society, ponsorAPS Liaison o IEE Pess, obert J. Mailloux

Techncal Reviewers

Mak Montose, Santa Claa, CA

Stephen A. Sebo, elsi ni Univesity ofTechnologyuh Denny, ecat, GALivic Poles, anscom AF, M

Books of Reaed tees from Pess

ENGINEEING ELEA PABILIY END EDINW Pasad Kodali2001 ardcove 476 S 0-78034743-9

ME-HOIC ELECAGNEIC ELDoger arrington

2001 ardcover 496 pp S -7-29806-X

FROTER EETROMAESDouglas Werner and aj itta1999 ardcover 819 pp IS -780-4701-3

EETROMAET SHARE AND EETRO EQUPMETan oxleitner

1999 Papeback 28 p ISB 0-780-589



LCROANCANH HBS Funamena esgnd pciici Gid

LLN MN

IEEE Electromagnetic Compatibiity Soiety, E Antennas nd Propagation Society

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JO LE SOS C UBLCAO



This tex is printed on acid-free paper. @Copyigh by he Isi of Elcrical and Elecroics gineers, nc All righs resvedPublished simulanously i Canada

No par of his publicaio may reproduced sored in a rrieval sysm or transmid n anyfo or y ay mans, lecronic, mecanical poocopying, recording, scanning or oise,ecp as pried nder Scio 17 or of he 976 Uid Sas Copyrigh Ac, wihoueiher h prior wrin pession of he Publsher or authorizaion hough paymen of happropria pcopy o h opyigh Claac C, Roswood Dri Danvs, MA3 (78) 7584, fa ) 754744. Rqss o h Pblishr fo pissio sold barssd o Pissio am, Joh Wily

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COTETS

ForeworPefce

1 roucion

1 1 e et ganzatn

Rferences 2

2 easuree Pic ipes Pei to echoiCaber esig

ndcn 3 eaeen f ecaec Fe

1 ntdutin 4

Antennas

23 Radated mssins 7 Radiated usetibility 722 5 Mltay letmagnetic Cmatibli

22 6 Antenna stem satn

22 Rada Css etn 8

23 Feeace est euements 8

21 ntdtn 8

3 2 Pase 9

2 3 3 Amd 1 1

23 Plazat 12

8

8

xiiixv

1

3



v COTTS 3 5 The Fiis Trasmissi Fu

4 uting Measeme Cces 3

4 ntducti 3

4 Cdiate ysems a Deice Psities 3

43 Decibes 4

44 ecs f Reeced egy 5

2 5 ects f Antea Cuig

5 ud Measureme aci iies

5 tduci

5 lectmageic Desig Cs ieais a Citeia

5 3 evae udr Aena Rage

5 4 Gu Reecti Aea Rge

5 5 eArea Tes ies OATS 3Refeences 4

3 Electogetc bsorbg erls

3 ntducti 2

2 Miave Asbing Mateials 28

3 Pyamidal Absbe 8

3 Wedge Absbe 35

3 3 Cue Micae Absbe 35

3 4 Multilaye Dieecic Absbe 373 5 bi ieecic sre 3 away srer

3 3 LFequecy Absig aeri 4

33 tuci 4

3 3 Ferrie bsbrs 4

3 3 3 ybi Absbrs 44

3 4 Absbe Meig 44

5 Absbe Tesig 46

Refeences 4

4 he hber Enclosure

4 tductin 4

4 2 letrmagetic nefeece 5

4 3 Cl ig he irme 5

44 letmageic hiedig 5

44 Iructi 5

27

4



44 Th Wldd hild 5

44 3 Th Clamd am r rfaricad hild 5

44 4 Th ihild Sysms 54

45 ris 54

46 rfrmc rficai 54

4 hidd csur Grudig 54

48 ir rci 55

Rfrcs 56

echoc Chaber esg Techques

5 rdui 5

5 raic Dsig rcdurs 57

5 rduc 55 Qui sim f Chmr rfrmac 58

5 3 Daild RayTraci Dsig rcur 6

5 3 Cmur Mdli 6

53 rduci 6

5 3 Ray Tracing 6

5 3 3 iDerc TimDmai Mdl 68

5 4 Ohr Tiqus 6

5 5 As sd Achic Chamrs 6

55 rduti 65 5 Rtuar Chamr As

5 5 3 Aas fr Tard Chamrs 70

5 54 MI Chamrs

cs

Te etnl Ch ber6 rui 3

Ts 3

ru 6 Dsi Csdris 4

6 3 Dsig am 5

6 4 Accac Ts rcdurs

6 3 Radr Crsscin Tsig 8

6 3 Dsig Csidrais 8

6 Dsig aml 84

63 Accc Ts rcdurs

85

COTTS v

7



CONTENTS6.4 r 85

64 Iruci 8

64 2 Chmr Dsig Ciris 87

643 Dsig ml 88

644 Accc s rcur 8

6 lcrmgic Ci il iy sig 8

6 Iruci 8

5 2 Chmr Dsig Csiris

6 3 Dsig ml

6 4 Accc s rcurs 2

66 Immuiy sig

6 6 Iruci 2

6 6 2 MSirr s cili y 26 7 M Sysm Cmii liy sig 4

6 Dsig Csiri 4

6 2 Accc sig 94

Rfrcs 95

7 e Cac ae Cabe

Iruc

2 A si 8

7 2 rim cu Cc Rg 8

2 Dul Rcr Cmc R

Rcr Cc g

4 Cc A R rr yu 4

Accc sig f h Cmc AAcc Cmr 5

7 Cc RCS s

ruci

7 3 2 Dsig l 6

7 3 3 Accc sig 8Rfrcs 8

7

cain ee i echc aber esig

8 Iruci

8 Tr Cmr

82 Iruc

8 2 2 A sig III



8 2 Raa Cetion Measuements 1 2

8 The Dobe Chambe 1 2

8 1 nton 1 2

8 2 Antena eting 1 2

8 n and mn etng

8 e Miss e adaeintheLoop Chae 8

81 nttn 128

8 2 Desgn Cndeations 1 28

8 Degn ape 1 29

8 Aeptane est Poeue 1 0

8 5 Conlate Fae

851 ntutn 11

8 5 2 Desgn Cndeatn 1 18 5 Degn ampe

8 5 Aeptane Test Poeues 1

8 The TM Ce 1

8 ntoton 1

8 2 T M Pnipes of Opeation 1

8 Typal Pefomane 1

Referenes 1

es Proceures

9 1 ntution 1 7

9 2 Asore Testing 1 7

9 2 1 ntouton 1 7

en cave Ae 89 2 L-ency Testin 18

. 4 ompat Rane Reeto Tetin 19

9 2 5 ieRetaant Testin 1 0

9 Mioave Anehoi Chambe Test Poeues 12

9 1 ntoution 1 2

9 Feepae WR Met

9 Pate aon Metd 8

9 X ane Metho 99 5 RC Cabe vauation 1 5

9 MC Chambe Aeptane Tet Pee 5

9 ntton 5

9 2 oumet te Attenuation 5

COS

3



COTTS4 ie ifor

9 5 hieig ectiveess 8

Refeeces 158

0 Expes of Idoor Elecragec es Fac es

1 Itouctio 1

2 Ate Testi

1 2 Itrouctio

1 2 2 Rectur es her 1

1 2 3 Tpee Aechoic he 1

1 2 opct Re Test her 2

1 2 5 Neie Tes her 14

1 3 R ossectio Tesi 141 3 1 trouctio 4

1 3 2 opct Re Rr rossectio ci ities

4 M Test hers

4 Itouctio

4 2 issio Test hers

1 5 ectogetic yste optii ity Testig 4

151 Itouctio 4

1 5 2 Aicft ystes

1 5 3 pcec Test ciities Refeeces 9

Apedx A roceue r eerg e Area Specur Absorber ree

A troo

A rese o A 8

ppex B es Reo pude Tper

B l touctio 1 8B2 Ate Dt 8

ppedx C esgSpecfcon Check ss

l Itrouctio 8

Te Rer

trouctio 1

2 Ate esi

8

1

8



COTETS

G

3 RS Testin 1 9

Nearie Testin 1 9

M Testin 1 93

solato Test 1

eance Testin 1 9

3 oact Rane 1 9

3 1 Introuction 1 9

3 AntenaRaoe Testin 1 9

3 3 RS Testin 1 9

Shape hamers 1 95

1 ntrouction 19 5

Tapee hamer 1 9

3 Doue Ho hamer 1 9 HarareintheLoop Testin 1 9

Shiein Desin heckist 1 98

1 ntrouction 1 98

hecklist for Prefaricate Shie in 1 98

3 hekist for Wee nlosues 1 99

heckist for Arhitetura Shiein

onventiona onstruction 1

Fire Protection

References

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FW

At at, a andbk f eetagneti anei abe! A inge e fndaenta, deign, eifiain, and teing f anei abe itten byne f e eading eet in anei abe deign and atie Leand He-n a bght ethe any daate efeene t a vi in te at eetmanet meaemen e aneh habe

hi andbk een a aj te f anei abe indng e-tanga, taee, and dbe t ine a aj eaeent tenie a afie, mat, an neafe teting t a adee a aj tyef eaeent, ining antenna, aa etin, eetagneti -aibity, adiate eibiiy, an aiae eiin

A key nent f eetagnei ane ae te aea ed tve al neo ae the hambe he en a hambe hne on hee eeion an aeent he abbe n the va fae theambe, nn he bak a, the ea ea zne, he , an -ne the habe he hanb ne neth n f he ye abbe, he hae abbe, thei eeivi eie, and the eae-men ehne e et he abobe

Ovee ie h a ihtng, ventan, ie otetn, hgh oe

eing, an eetane ieing ae itant n te fina deign and ei-fiain f an anei abe i andbk ie ti infain a e

i anbk a inde te ian i f abe e edeand aetane teting e eing tenie eented inde abbe te-ing, fee ae atte main, X anne, and evaatine ba i f ea enie and e ee t ay t ea tene e-ented ave fn tat it eidi teting and dentain, and be-en ebment, hambe efmane an egae ign ifianty



v ORORD ae ecome acue aae o c o omao ea e e-

si pope use, pefomance measuement an speci fication fo aechoic cham-bes in my teachng an eseach on antenna aome an aa coss sectionmeasuement technues ove the last 35 yeas Ths s especal tue fo the new-

e measuement techniues such as compact an neafe measuements pe-fome in an anechoc chambe It i s ith geat pleasue that thee is now an au-thoitatively wtten hanboo that can supply the neee infomation fo thisimpotant pat of electomagnetic measuemet

Hemming has chosen to inclue only the wellestablishe timeteste tech-niues an infomatio I ecomme this hanboo to al stuents an pacti-tiones of electomanetic measuemt

B rofessor erituseorgia Institute of Technology



EFCE

I fist eame invove in the esign an/or pouement of anehoi hames in when I was responsie fo pouring a uamoe anehoi test fai lity. Thefi i ty was esigne to house a ompat range for apetues up to . m an aowfreueny tpere hame that ou opeate own to M. he physi-al aangement that we eveope utilie a ommon antenna test ositone lo-ate in the test eion of the tapee hame. he wa of the tapeehame was esine to open up an evea the ompt rne eeto. Sine

h tie I hve o ee aeia on aneho mateias n hames. Suse-enty I e hief esigne fo two ieen aneho hamer manufaur-ers ove a l e eo . n 1 98 I etune to my riry caee ativity as an t oin as rtte onsu ltant n e p y is rrent on t t-oy. is oo s s on tat xeiene

e ne or inoor estin of eetomanei riatin ves whh eanin te y s se hapter e. ] has o a nume of ompanies po-viin hames an asoe pouts supporting a ange of eetomagnetitesting euieents. The testing euiements range fom hanhel telephone

antennas o whole vehie testng of atmbiles o a a. n ecent yeas teproiferation of potable eleton evies has e to the potential f extensiveeletomagnet intefeene beeen vaius pouts. Beause of ths ptentialinteferene various govenment agenies thoughout te wol have ha to setup emission an immunty test euiements. This has le to the extensve use ofinoo eetomagneti test fail ities see Chapte 2 Re 2 . These fail ities in-luing the more onventinal hames use for testing of intentional adiatssuh as antennas ontinue to a to the numbe of anehoi test hambes wol



v PRECEie n e erospe insry, i s oon o es issiles, irr, or similrweapons patfom fo thei aa rossseion in an attempt o eue etetabi -ity by means of aa A of these various esting reuiement have e to a eieof peiaize tet fa ite to aomsh he reue testing hi book eview

the uent sate of the at in noor e letomgneti testing fi ite s an thei e-sign n speifition

A gossy eating o eetromagneti mesurements n nehoi hambesis inue at the bak of the book, so hat e eae w be abe to foow the te-minoogy se in onjuntion wit a piu anehoi hambe eign

he pupoe of thi hanbook is to provie the eignepoue of eeto-magneti hambes wth a singe soue of patia infomaion on the angeof anehoi hambe egns nue ae hapte on a age variety of anehoihambe use fo a boa ange of eetomagneti measuements that are om-mony onute n inoo tet fai itie s uent infomation i gven on mea-

suemen theoy to suppot the hme esign poeues povie n eah ofthe speifi hambe esgns es fiiies for te measurement of antennas,satterng (R, an eetomgnei ompib ity ae eaile fo a vaety ofaneho hambe onfgurtons An exensive set of phoogaph i provean emonsates the boa range of anehoi tes fi ities tha have been buil t tomeasue vriou types of euipmen A speia oor seion is povie hihighights some of the moe nteesting aneho est faities that have beenbui t to sove vaou easuemen pobems na y, eigpouement hek-i t ae povie fo eah o f the vaiou chambe onfiguations

am soey eponibe fo he eica infomion inue n this han-

book Ts infomation was oi ie fom he many suppies who epone tomy eest for etaie aa on thei asorbe prous an fo pitue of theieo er insllions

AKDGMTS

nk y fe, Val, for er nening sppo uring e ee yea i ook toompete his projet m espeily hnkl fo he help provie by Dona JMatin, a cowoke at oeingMes, ho poesse a the ato an pho-togaph nto gta omat an eate many of the awing Many tank go to

wa Peton, my fome upeviso at MDonne Douga eooge, opoofea the fna manupt, an fo hi uggetion on ome of teaan pesentationa iue inay, my hank to the vountee evewe fo eisuggetions an eommenations on he vaious revision of he book, to the Pess, an to the John Wiey ons sta who woke with me o the inapepaton an pubiaton of his esigpoueent guie

esa ronaay

MM



ECOMAGETICACHOC CHAM



CHAPTER 1

INTRODUCTON

1 .1 THE TEXT ORGAIZTION

Chapter 2 s devoted to the prnples of eetromagnet measurements that per-tin to nehoi chamber des ign The onept of lane waves unform fieds andunform phase re given to establish the basis for determining the ropeties of radatng or sattering deve in free spae Also dsussed is the mpat of themeasurement site itse lf on the uray of the measurements For a ater ompari

son the rnces invoved in the design of outdoor test ranges are describedReferenes speifi to each chamber onept are nluded in the indvdual s e-tons General referenes applable to the general fied of eletromagnet testfa tes are ncuded n the Seected Bbiorahy.

Next n Chapter 3 , rado frequeny and mcrowave absorbng aterias are de-srbed w th det ed nformation on ther erformane and how they are used toestablsh contro ed electromagnetc test environments wthn n ndoor test fc ity

Chater 4 rovides nformation on the chamber enosure. If eetromagneticshied ing is requred common avaiabe systems are described wth references de-

tang ther construtonChapters 5 through 8 deta the desgns ofthe varous tes t fac tes broken down

b the geoetry of the test fat hese nude the retanguar habe the

ompat range hamber and the habers hee geometry i s mportant n thedesign nudng the tapered hamber the doube ho hamber and the TEM e l

Chapter 9 summarzes a the tst proedues assoated wth eetromagnet

aeptane testng of the varous hambers and aso the testing of absorber mate-a s used n the onstrution of the hambers

1



2 RODCO

Cae 0 vde a ay e ye oo e cil iie h hveeen evelope o the vaiou electomagetic meuement. ee cechame o tetng nenna, a co ection, elecomgetc atbty,an eectomagnetc ytem. xtenive ue o photogaph ha d t -

utate thee vaou anechoc chambe. A peca ne f o o-togaph ha been cue to highght the eign concept ue aechocchame eig.

Appenx C povie a e ie o eign a peci caton checkt o the va-ou type o anechoc chame.

A eecte oaphy i g ive i uppot o the content o the book.

A exteive ex i vded a vee eeece c e mae to anyje vee y t ex

EFEENCES

I W Eerson Eetroaneti Wae Absorbers and Aneoi Cabrs te ears IEEE ransacions on Anennas ad Ppaaon o A 1973.

2 B. arene Aneoi Chabers Past and Presnt Conformi 6 o pp5456, Ari 2000

3 EEE Std 145-1983, IEEE Sandar Deniions of erms for Anennas I rsse ork 1983

ASI C6314: 1998, Aeria ationa Sadard Ditionary or ogi eraneti Copatibiity EMC) Eetroaeti se EM) an ati

Diar ESD)

5 . EEE 10, h Ahoriive Dicioa of IEEE Sandard erms 7t n IEP ork 2000



HAPTER

MEASUEM PES EANG AE AM B SG

21 INROION

The pupose of the book is to pove a guie on he esgn an efanespeifiaton of eetoagneti anehoi habes o no te faiiiesHoeve, soe koege of eetoagnet eaeens ee o en-sue that a ap abe egn fatos have been ae in any gven egn sa-

tionThe easuement o f eletoagneti aves nvoves a age nbe of ee-

toni evies These evies an be ategoze as intentona nnentinaios esuemen of inenionl ios (such s nes o he scae-in of eletoanei enegy, s in a oss setion, euies speialze es-in fi lii es Deeminin the level of iaion fom unintentionl aiatos suhs ii l evices o eeminin he l evel of imuniy an eleoni evie hsih se o n impinin eleomnei ve lso involves he esuemen of eleomgnei ves in esin facil iie s esigne speifilly fo hemeasuemen to e pefome

etoagnei aves esut fom the aeleaton of eeti hages Theeleti fie l ue o an naeeate age (one at est o n unio oton in astaight lne s aiay ete an eeases as te sae of the stane foe age Hoeve, the aeeation of te hage gves e to a tangea oponent of the eet fie, an hs eeases neay h sane 1 tievayng eeti fe has assoiae ith it a te vayng agnet feogethe, they opise an eeoagnei fiel An eetoagnei fe thateeases lineay ith istane epesents an outa aaton.



PPE PER O HO HBR DE

n pae, one amot aay concene th maocop ee eunfom aa f g nbe of hage On he maoo ae, he neeah beeen ee an mane fe ebe aheaayb Mae ' a 2, 3 A ana f a aed v

eaonh 3 , pefe he haaes of h mu n hh he fee

he mahea of eeomane fe an the aocae mea makeue of veo and eno anay he ana an beome vey nvove nmany pobem, epea hoe nvovn popaaon n nonop, nonec-poa, nonnea, nonhmoeneou mea Athouh cean pobem neetomane meaement an eue appan of moe ae mahe-ma, ony he eavey elemenay apets of vecto anay an eetoma-net theo ae ue n th book The eae s aume o be fama th ba- ve peaon a onts of ave henomena tana et, sh a

he efene e n h an subeent haptes, hou b onulte aneee

2.2 R OF EEROGI FI S

2.2.1 Itrodctio

he va o f eeoagnet fel meauement hnue fa eenveTh fng eamp eeent a sampn f he m mmn e ofmeaeen an he paamete, hh ae aee by he etn envn-

men

2.2.2 t

o. Antenna measuemen ae etenvey conuehouhou n an oveen te fate hee meauemen nvoveeena o ba paamete he f he tbuon o f he aae ene-y n pae abo he anenna o anenna pae an aoae an he e-on paaee h e the anenna mahe o the anmon ne feenth ana n man

The eneg aae f an anna a ha b h ae hap an b nea ha a he engan be ee n ne eton, h a that eneae b a age eeo annna he fa e f meang antnna va geat, epnng on the peof he antenna yem an he pe of patten eeae Loan o e ea- mal anenna an be meaue n smpe angua hambe n he moave feueny ane, but eue peci y ee chame beo 1 GHzue to he abopon popee of the anechoc matea hat mut be use at helo feen ghan antnas vey on ength otoo an o



O O D the ue f mpat antenna ange in ah f hee ieent faiiie ap-pximate the iea te enent ayig degee f pefane . he i f-feene i be ied n e fng apte in njuntin ih he e-ign f the paiu a fai ity e fing i genea infmain that appie to

al faitie.Figue . 1 epit a geneaze antenna paen. A maj be i hn ih

it hafpe beamih nte he ie be ee ae a nte e gan fhe antenna i efeene e peak f e ae e aa f the meauepatte i a funtin f te ee f etane eneg eiing in he tet egin fthe antenna tet fai li ty. f he etaneu ee i 5 , then he iebei have a B uneant aiae th the meauement. Figue . iue t evauate the egee f uneain that apie t a given meauementknoing the lvel of extaneu enegy that exit in the tet egion an a givenpattern level.

... Te Tet Peue f Antenna t 1 9 5] efine the poegain of an antenna in a peifie iein a ime e ati

Ha

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6 AURN PRNCPLS PERTAINING TO A NECHOIC CHAMBR DSIGN

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Figure 2.2 Paen eve uncetainy vesus exaneous sgna eve .

of the pwe aae pe uni so i ange in haecon o the net poe accep-e by the antena fom is geneato. Ths i s escbe mathematca by

G(, 8) = 4



MESREME O EEOME EDS 2224 The input ipedane o an antenna is inu-ened by te physia l enionent adaent to the antenna Antennas adiate ene-gy and i f the enegy is eeted ba into the antenna, then the appaent inputece chge f he eecig oec gee h oxiely oe

waelength away o the antenna, then the easueents ae faily epesena-tie o the atual input ipedane the easueent is to be onduted within sall RF absobe lined enlosue, then the eetiity of te absobe must beseleced caelly s pointed out in Chapte 3

22 Eiions

he easueent o esions om eleton dee has beoe a e ipotant pat o bingng an eletoni deie to aet oot e wol oeent agenes now spe te aiu eso tt an eleton dee

an adiate e leels ae ey low de to te pesee o so any deies in agien oie enionent Cael alibation o the easueent sie is essentialbeause l age eos old lead to epensie eipen ie i the speed le-els o eissions ae not et Cuently, these eaeents ae ondted onopen aea test ites (A o in alteatie indoo stes s as aneoi a-bes hese easueents inole te easeent o the sie aenationtatis , te popagaton loss between te deie unde tet d te easeent aten-na Knowing tis loss and g a spet aalze, te eel o the eissionat a gien distane an be deteined Tese measeet ae geneally onduted at ange lengths aying o 3 to 30 Aehoi abes ae oon-

ly used o the 3 ange lengh Lage opanies hae built a nube o 1 0habes

The easueet spet that is ost ipotant in anehoi design is thedegee to whih the site atenuation is the se as easued on an AT e-ause the fility s onfined within an enlosue, the epeatability of the mea-sueen wn te e olue ust also e eiie A t ite oo to lE mesueents s the unetainty soited with the antenna used theesueents n how they ae libte

224 e lRadiated suseptibility euies the easueent to be odted in a sieldednehoi habe beause high leels o powe ae eed to eeate tefields neessay to test the susepibi lity o a deie to aos leel o eletoagneti ield s Cael design o these alte s eied to ze etainty in the easueents Deiled inoaton is ie o te de o tesespealized test ailities e unioity o te e lat t deeunde test (DUT is the most tial paaete in eptiily eeens



MMT PCPL PT TO COC CMBR D

22 ta Electmagnetc Cmatb lt

Militay adiated eletoagneti easueents ae onduted in shielded anehoi enlosues using test poedues and absobe teatents speiied in ML-STD 8 ]

22 te te Iotion

Antenna syste i solation easueents equie a vey lo extaneous signal envi-onent A lage lea aea aound the vehile unde test i loated otdoos is e-quied A l age test volue is equied in an anehoi habe ndoos the siteisolation is the su o the toay path loss to the alls plus the eetivity o theabsobe The su should be at least d geate than the syste equieents topoide an adequate signaltonoise agin o the easueent A speial ase o fthis type o easueent is the easueent of passive inteodulation (PM ]

227 Rada ectn

he easeent o ada oss setion has speial test envionent eqieents These inlde ( iniizing o oad sate o the tansitte to thetest egion ( iniizing extaneous enegy eeted o sounding sufaes (3 nio il luination o the taget in phase and apli tude and ( theabil ity to opeate ove vey bod fequeny anges 1 0] ah o these ites isdisussed in the setions desibing a patiula tes habe onept

REE-PE E REQIRE ES

21 Intdctn

he adiation haateistis o an eetoni devie in spheial oodinates unde a given set o ondiions an be desibed by the ntions

&

(5

whee and ae the gain funtions fo two othogonal polaizations is thephase angle between the otput signals o the to polaizations is te eiien-y of the deie deteined by its ohi losses and Z is the ipedane that the de-ve pesents at its input teinals hese elationships ae ill stated in Fge 3

nly i n the ase o an intentional adito suh as an antenna ae these p aaetes easily deteined n addition envionenta atos ust be onsideedin any eletoagneti easueent poble and suitable alloane ust beade fo thei eets



REESPCE TEST REQREMETS

igu 23 Symbolc elonship of mesued pametes

efoe poceedng o he speci fcs of eecomgneic testng ht is pefomedin nechoc chmbes s ppopie o eiew cein ndmentl ems ndeltions th e bsc o elecomgneic mesuements

2..2 Pe

A commonly employed cteion fo deeminng he minmum llowble sep-ton beween he souce ntenn nd he nenn unde tes s o estic he phasetion o be less hn aximu of 8 dian o .5 degees ]

Conside souce of spheic wes nd n ntenna unde test (AU ocatedt stn wy ro t s llstrt n ue 4 h l rst hs r

gu 24 Deiion o he fed ct



0 MESREMET PRCPLES PERT TO ECOC CHAMBER DES

ece eee e erc e e e e e er e ee the A, hich crresos o the ierece i he ae th leths, nerthe coo assumptio lfil s the reqiremet

n/8 (2-6)he ierence i the ave ath lenths , is eterie y notn that

(2-7

he only physical soutio of the aove qaratic equtio for is

(2-8

he aove is approxiate y the use of the ioia expansion (the first to

tems ony) as

R[(l + (Dmax/2R) R[I + 12(Dma/2R (2-9

he iimum istance from the source of the sherica ave is no eter-mie from the requiremet i (2-6),

KDax4R (2n/A)(Dax/4R) n/8 (2-10)

ner this coni tio,

(2-1

If antena mesurement re me at this re eth then there i l e i-or eparture f te ul ls of the raiatio patter a the location an l evel ofthe mior loes fro their infinitere lues

Equati ) as erive uie to settin ten easuremere o accurte eure e rii tter e cuct rrcrsssec i RS) meuremet, ccerns re t te ter o he rce reeie atenna, ut lluminaton of the taret. The prary requirement is thatthe source antenna has reatvey onstt amtue a phase chaacterstcs, asseen at the taret

These requremets ca e achieve ith the taret oser to the antennas thathe vaue cauate y equaton (2-).

o ushe teon s on for etermnn exacty ho ose the taetshou e to the soure antenna ome uiane as rove by u 1 2 , erethe phase ithin the 3B eamith is essentially the same as at nfnty for istce oR4 or .5D/A. Equaio ) c e eneraie to

(2-1)



23 REEPCE REQ RE

Whe e ccucy of 1 is euie, no 1 3 hs shown ht K shoule ewee 0 eei o he e chctestis he tyes of aesha euie a le vlue of K e hose i hich he ee scaein is com-le o the seculstten contiutio A oveiet cht fo eteminin the

taget size as a ncion oK is given in Fiue 5adated emiss on and ssetbiliy measements ae sally odted obot te nea and a eld s de to te bod eenc oeage ad te distanesset by te testing eements , 5]

2 e

Fo accucy in simuled f zone mesuements, te i llnatg ed mst besuiciently consnt in mli tue both lo te ln o ght and in anes nomal to the line of sight the eld unomity is not set aog te as, ten

measement eos wll o, esecially in the mino lobes f the atde tae acoss the etue i s too gea, e the meased attens w a signiicantl fom feespace o geomane antena anges te tae s geneal ly hel o be le ss tn 0.5 d, esltng i meased ga eo o less tan 0 dB ] Fo ne leh ofR = } see eatio ( ] , the soce diamete woul be esticte o

d 0 3 (13

whee d is he iee of he souce e , is costt, n is he im-ee of he AU

00

0

Tm

.

u

7

" t

V

V

V

v

V

V

3

2

.

.

i

/

2

V

V

V

v

r

t

0 00 0

igur .5 Test egion size vesus nge length nd feency

00



2 RT PRCPLE PERTAININ TO ECOC CMBR DN

or mos nenn mesures h u ro s he l o ess hn , hen he error is usully cc

24 Polrzio

A lre distnce from riti e he electric mnetic (vecors of he rie fie re t riht les o ech oher o he irecio ofpropion he wo fies osc e hs n he ro o her mnes ( i s cons h irinsic iec of fre sce, hs lueof proximely 1 0 ohs

The polztion of n electroetic fiel i s escribe ters of the irecion in spce of he electric fiel ] f he vector which escribes the elecricfield poin in spce, i s lwys irecte lo lie, which i s necessrily norml o the direction of proio the fiel is s o e ineay polrize nenerl, howeer, he terius of he electric vector escribes n e ll ipse, thefiel is sid o be eptcally porize

Riin evices exhibi olriio roeres rlio o he fiels heyrie or receive f ne is oere in he receivi moe i wi ll no ienerl be polzionche to he incie fiel f i is olrziomtche, i will extrc xiu oer fro he fiel n is po lrizion ecency s si o be uiy f is olrizo is orhool o he fiel wil exrc zero power, n s po rizion eiciency s conseuenly zero

he olrizion ropeies of fiels tenns re of rimry focus i llproblems concerne with comunictio bewee enns

2 e rs rsissio Forul

were necessry o r h oer rsr o nens y resori o the bsc rocesses h re fine by he fel euions n ifrcion heory, he ccuions wou be iry ossile or ll u hesmles of nenns he rs rssso ru ers he powerrnser o be eer fro olee o h sure recve roperesn he dissiive euo of h s o heir eile e n

= power receive = power trnsmitte

G(



2.4 SPPORT MSRMT COCPTS

2.4 SPPORING ESREEN ONEPS

2.4.1

e couc eec roec esurees s oe reure o ess coore syste ecuse the esurees re eerly coucte tree i-esos Also os electroetc esurees re couce eces ecuse he yc re of the esureets oe excee poer rtoof ore th l o es or 60 Aother prole i s tht he esureesre coucte er the erh or eclosure, hus he prole of reecte e-ery ut e ree ese three eerl cocept re cue the fol o- eco

2.4.2 n te e ee Pe

Ao eecroec rto esuree voves eero , oey or oter of eves s fucto of posto or recto spceuuly the tter ecuse of the ture of rto, he spherc coore syste ure 2.6) the syste tht is ost ofte eploye i elecroeticeureet prole Oe, the esuree of irecto ust e e o

/

:

F 2 Serc coores use e esuees



14 MEASREMENT PRNC PES PERTAIN I TO ANECOC CMBER DESIN

hh e f ecs ecse f e ees f he el sysem ofwhch the ece s

ecuse of the elely le sces h e fte eued bewee he de-ce e tes the sce e sml te (deedg o

whehe he dece s este ecev smtt, s oe o aclto exloe he dto tte of the ece (



PPOR R OP L = La + g( 8) + g'( 8) 20 g) (27)

wheeL i he ignl l evel t the ouu teminl of the eeiing nenn n dBm,

L the sgnl level t the iut temnl o the tnmttng tenn n dBm, the g o the soue ntenn,g' i the gain of the eceie antenag(, 8) 0 log G(, 8),g'(' 8') = 0 log G'( 8), ndR i the nmitteeeive eion nd = wvelenth.NoeR nd mut be in the sme uit (uully mete) of meuedm is the igl level i owe efeenced to m

2.4.4 Eects of efecte Energy

Whe two o oe oheent electomgnetic ignal combine in he et egion ofn electomageic tet facily the field illuntng te deice unde tet aedioted and he acucy of the meauement deaded.

The diuion hee ume eation, , beween ouces ad eeingnte eual to o gete thn 2 (see etion 2 2), whee i the mimum dimensio of the eceiving aetue i te umed th the atio i mall i coaon wit the alfowe beamwdt of the ouce ntenna'ate, o ht le wave aoimtios ae meangl.

The mehai m by which eeed ignal intefees wh e deied diet-

h ial d diot the iident field i demonte s follows. Conide thece o diectah lane wve of amlitude ED tht i nomlly indent on ate aeue, a hown i Figue 2. et eeted lane we of mliude ERete he eue t ngle 8 fom the nomal. The dial lie deined by theunit veto i he iteetio of he le ontining the dietions of og-o he eth eee sls the le ot the euehe lie hvin unit vecto i t ome geel ngle fom u in he lane of thetet etue. At ny ien time t the he of the diet we i onstnt oshe etue, the mnitude of the d ieth fiel my be eeed in h-so ottio s

(28)

The he of the oulted eected lane wve w ll ay o te eue otht the mgnitude of the eeted field long the line o any lne llel to ige by

2 9

(2 8) and (2 9), nd e onnt, the wvelength nd a d-tne eued along the dial line o long ome ote lne alel to Te



6 MESREMEN PRNC PES PERN N TO NECOC CMBER DESN

\

/

: \

I \ " 1/ I

T

/ . Iv

J

igue 2 uo of o cohere ss

magnitde of the totl fe esure s fucto of istce o i be

ootionl to

v s s he i sce beee successe es of e esu siuso fie s

P = s cos hs s eriod or ich hs u vue of

P = s 2-22)long the direction u as sho in ige 2 While the satial eiods of the easred field uctutios e nctions of the

osition of the dil le i the erture for hch recodin of the fiel sde sin field obe, the ektoe mitude of these uctutios is cos oortio to

(2-23



2 SPPORTN MESREMENT ONEPTS

ie 28 ecor on of o coere n

or c ormc ern e ro of ER nd ED o e

2-24)

ere e erence n ece eeen mm n mnm of e eure ern o of ER/ED er en n Fure 2

Te recen empe emonre e mnner n c reeced n

o or n oee nr e fron n more rec ce neer herec e nr e reece e e rc pnr ere o emn orce f erneo n co conre e o erurefel oeer e e oe reene oe qe ef n errenfe roe for e c ce ee e reece metonge tn ote ignl tt m be peent An ltentie meto o err e e e er

24 ecs o e Copi g

e oer freqence e eec f nce con eeen e orce ne e nenn m e conere ] Te ro of e me of e ncon fe o f e ron fe en

P = /2)If one me O , en 20 P 36 dB

2-2)

Muu co n e o cern n reron of e ener e e norce nenn o of concern f con doe occr freqenc n n



18 MEASUREMET PRCPLES P ERTAINI G TO AECHOC CHAMBER DESIG

C:Q":;

aEQaa

QI0-

Q b

9

7

6

5

4

3

2

019

8

7

6

5

4

2

0 019

8

7

6

5

75

1

/

/

/

/

/

/

-65 -55 45 -35

igu 2.9 Plot of rror vrss xtraous sga l level

/

/

/

-25



ODOO powe leel aes an b e edued by isei a i solao o aeuao beweee soue ad i aea

2. OOOR EREEN IIIE

2.1 Itotio

efoe poeedin io e desi of aeoi abes a be eiew o oudoo es aes is euied o e sae

e ideal es eioe o deeii fazoe efoae would po-ide fo a plane wae of uifo apiue o il luiae e es apeue Vaiosappoahes o simuation of tis ideal eleoanei eio ae ed othe eolution of two basi types of antenna test aes ( ) feespae anes and(2) eetion ages

Feespae anges ae hose in wi an aep is ade to suppess o eoethe eets of al suoundings in ludin the ane sufae o sufaes alon ewae font that illuminaes the tes anea This suppessio is so hohone o oe of suh faos as

Dietiity and side lobe suppession of e soue and es aenna

2 Cleaane of the line of si fo he ae suae

Redieio o absopio of eey eai e ae sufae

4 peial sial poessi eiues su as ai by odlao of e

desied sial atin of e sials ad iedoa eiues o by useof sho pulses

ypia eoeie s assoiaed wi e feepae apa ilde e e leaed ae e a ae eaula ae abe e opa aed bv e l mt g s t taeed hmbe

Reeto aes ae dese to ae use o eey ta eadated om teae sufae(s to eae ose ieeee w te depa sial ite eio about e tes apeue e eomey i otoled so a a setisma ll ampl tde tape is oued te lmia el e two majo es ofeetio ages i use ae te oud eetio ae a o low feuees thetaee eoi ambe and te vesided emss o ambe

2..2 Eetogeti eg oieti itei

Fo eie basi type of ae e ndameal eletoanei desi ieiadea with ool of

nduie ouplig bewee aneas

2 Pase uaue of he illuian wae on



20 MEASUREMENT PRINCI PLES PERTAINING TO ANECOIC CHAMBE R DESGN

3. Amlue ae of he llua ae fo

4 Satial eiodic aations the mia ae font cause by eec-

tios

tefeece fom suous aat souces

tems I thogh 4 imaily establih the dmensonal euiemets on the ane

desg as wl l as l mtn the soceatena dictvit Item 5 mst be consd

eed in the oveall desin

2.5.3 Elevated Outdoor Antenna Range

Eeate antena ae es proceeds as fol os (see Fiue 2. 1 0) :

1 Deemine the minimum rae eh fom he ae equatio,

(226)

2 Detemine the maxmum ouce atea damete whee the amlitde ta-e is l imited to 0.2 dB,

heed = souce iameerD = test aeteR = ae leth' = oea aee

SOURCE

d $ 037 'RID

Figure 2.10 Eleaed aea ae

(227)

TEST

i



2 OUOO MEASUEMENT ACLTES 21

y R KD/ c c

$0 .37 KD

A c v g dg v R h

T u g u p u g cs, cc t f f th c p fls h th f I f fu dc f cs c cv y fc [ 1 ]

2.4 Gou Rfcto t R254 1 ntrodution T ud c a sg us y f sc c pt f c h sufc f tt c ts pt A fx fqucy g p- c us t th cng gy s phd so s catccv c t cpt s h f t p

2542 Priniles Th ptu tp f utg fd g hl l g tst p ol f , d-

d y y suc cvty, t p d, h f v Th p vc u ptu v vtuy p f cvy f hc pns lt y t gt f c f tst pu v sufc Ts y sh sc h fl-lowing paragraphs.

y ch S f-c f h cth v c c lc dsp th p l f dc d -c v T h s h l f h ld n

vc r c

h t m pc suppssd I s xps,

2/

RD = [R2 +(h- ht)2J 1 /2

R = [2 + (h+ ht)2J l /2

229



22 MESREME PCPES PER O ECOC CMBR DES

_-k-? D

SOURCE _ _ / . _ h

4

-

'

--

-

lGE

w ig 2 Grou reectio re = the recth fie mite

kej = n eecve eecton coeic iet for the rne surfce = ec pt engt = reec ion th legth = ne enth

h = e o nst ntenh = eg of eceve nte

ssum ht the hse shif fo tc ou reecto geomet s nealyeu to rs tht the rge lenth s le wth eset to theheiht of the trsmit source is ive omately

(20)

Whe he teference oe s peke he e hgh e d o

s on e oer of

2 )

To esre tht the vertic m itue vritio cross he test ee o n onreecto re is suciety t, it s recommene tht te tes heght h e set ]

(22)



C f e eetis i e ide a a ua a a, a a ula a aun die atten to toe odui eentia ua eon i

aua An, a g da a a en ua and e ntolled aea t dn ouan a a eial

Fo te ae ufae vaatn, it i sutd tat eaktak ufa vai-ation be eld to wtin

( n we

te opatg waveeng at te hghet fequn of n

a mn ato bwn 8 and 2 atan( + )

(2)

F aunt f ane uae aa to be onll udan vn inef

255 Ope-e est ites (O)

ntdtion The Fedeal Counat Cin (FCC)

wa given th au t ule and eua a, a ,and onume dv tat a aiate ela u Co-uat At 9 a aa t(A), a if f ou eto a, a a nv td otaaz at 7

he na seccan secd ha adaed essns ee e cndutd on a ound lan uin te ane l 3 , 0 , ad 0 A uit-able ite equid tat it be la obtt u a , b, etalfne witn an eltia buda Te t a be wl awa fmbuildin, aed autooble, and te like Te utablt of te ite i dete-

mined b meauin te ite attenuation 4

2552 The Design of Oen A Test ites naea te e agundetn ae wh efed ang ln a e et anfo te annn atnna tat ae ued to meaue e adad mn -ut tat te t ave epatale aatet al, h ttuatn,wh i dfned a te poaation lo between te tm und tt a t ma-uement antenna, beome a quanfable paaete Gven th e anatn



L R T H HB D

te eve of aiate eiion fom a device nde tet can be aate Ti ia te o eeae n necoic abe tet ite

e ein o oenae tet ite i now specifie b A C 7 992 8 An etenive iu ion iven b Koai

e vidt of te tet ite i eteine b measin te ite attenation aeibe in A C.4 4

R

. . D Ka, a D . leisch lectromanecs: Wth Applcaions McawHil,New Y, 99.

Uaby, ndamentals of Appled lectromanetcs. 99 eiti, PeticeHall,New Y, 9

3 C . , nneern letromanetc Felds ad Waves. h Wiley & S,New Y, 975.4. C . Balai, nneern letroanets. hn iley & Ss New Y,

9

5 I St 47, Standard Test Proedres or Antennas

6 Ka, nneern letomanetc Compatbli. n eii I Pes,

7 B awece, Aechic Cher Pst an Peent Conormi. l. 6, N. 4, pp556, Ap .

ISD6 Reqirements for the ontrol olectmanetc Inteerence Char-

aceriscs obsysems and qipment9 pal iPa ie Itemlati, Antenna easrement Teciqes Associ

i ci pp 31 . Kntt, Radar Css Seto easemets. n Ns ei New Yk,

993

. S H et a , icrowave Antenna easrements. Scfic tla, Ic., 9aaabe D fm MI ecgies, Ic , Ncss, GA).

1 igKe H, enel egin ie stributs f icua pete,I ransacons on Anennas and paaton. AP, pp 34346, May96

3 Kt et a, Hw a is ar? I Transactons on Aennas ad Ppaaion.l A, pp 7373 Septebe 74.

Ameca Naal Staa Iti te NS I , C6 3. 4 : Staa f met fmea f a ie emii f lwltage electa an eeeqpe e age f 9 t 4 H.

5 pa aa, N6 43 : 996 l ecagetc mpatibly Pa43: eg a meaemet teciqeraiate aifeqecy, elecmagetic fi mmty est

6 a F, A te a imple asii la, Proceedis o te IR. 3 , N 5 , p . 54, 1 937 .



REERENCES 25

17 Chaactestcs f pe el est Stes, Ben OST eeal Cmmcats Cmmss, ce f Scece a echlgy, Washgt, gst18 .

1 8 S C3 . 7 1 , meca atal Staa f Cstct f pe-ea est

Stes f Pefmg aate mss easemets



CHAPTER THR

ELECTROMAGNETICABSORB I N MATER IALS

3. INROUCION

lectomagetc aog mateal ued i aecho tet lte tae mom, depedg o the pupoe o the aclit ad ue o opeto hetwo ot omo ae the dielectc aoe ued the owe eueage ad the eite aoe ued the lowe euec ge Dielectc a

oe came aout eal i the deelopmet o aeho hame dug the0 whe idoo tet acilite wee it deeloped hee ealy chamewee lied with matted hoe ha that wa impegated wth a coductve a uee m w ud d c coductive outio, ad e pamidalaped aoe came ito eig Welito th 0 , t oa dielecc ae wa the pima poduct availae cc cm ppca T e ou cme e ccd wc caued t ovem each te ie etadat popeti oaoe ad develop a ew ie aet tadad The oam aoe ow maketed ut meet the euiemet o aval Reech Laoato RL) 80

hi documet pec iie a ee o laoato tet to peomed to povide a gade o aoe that ite ieetat Fo moe detal o the hito o aecho chame, ee to Re 2 ad the late 0, a maetdevelope o loweuec tetg wth a doo chame The t o theeacilitie ued the the aailale mateial, whch wee lage aoe pamditalled withi hielded ecloue to etalh a acceptale tetig eiomet Thee acil tie wee ve expeve, ad ol the age compae oulduppot the cot A the demad o ailitie oe othe oluto wee deel



RM BRB MRL

opd, d th td chm cam ito commci u od th e ouc o th it mati Mot uppi o choic ciliti povid dg th g o mtia Th thoud o th chme wodwd dtid hito o M mumt gi i Chpt

o R th 0, chm o tetig wi di ecm th ogue,ad a i o w chm dig w dopd 5 l o oig mtil ud i achoic chambe ae viwd i thi chpt Fo coveic i ptti, t ctio i ok dow ito two mati ,tho tht ud o I GHz micowa) ad tho ud ow I GHz owuc)

3.2 RWE SRIN G ERIS

3.21 i oe

3 m Mot o t lctomagtic achoic cm mauacu o tdad micowa ao poduct that i pamid i haph poduct o id coloadd uth om o To mt th cuti tdc umt it odd with itdat chmcl tht ith mxd i wth th co outio o addd a cod ttmt h pima ppcto o thi mtil i i th cotuctio o chic chm, ocog tt uipmt withi th cm a l ow o, t poideth hgt odd pmc t oth om icidc d t wid cidc g t pm ud o ducig od cttig, ut o good

ack cttig popti a wl , makig it uita o u a octo withi a aechoic cambe t i availabe i a vaie o ticknee t ovide tecamb deige wit te oouiy o co e igt poduct o ecicuci d ic idece age

iduty oid mateial a mall a 5 cm i igh ad a tick a m h poduct galy com i tdad ticknee pecial cuta o mad o pciic aplicatio Tal ummai commo pamida mtl avaia om the micowav matil idut wo gomtiee the tght uae pmd how u , d th witedpmd iuttd i igu h tt i ud o th lg pmwh th houd o th pmid hlp c th od o th ctgomt, iuttd i Figu h twitd pamd i commo ud ith cw o tpd cham wh th ao commo ud up to 8 m ) thick

h poduct i ack w mad ad i uull paited wth u tx paitto impo ght ctc At 5 GHz, th pt c dgd o ctit much a 5 d, o th tp a o uptd i chm wh milimt mumt a to coductd t al o ha oud that i th tip up it mimz p ag du to wea ad tea oud omalchm optio Fom oe i ot v out ad ie a hig dg



M R BRB ML 2

able 3.1 Pamidal Aso Pomanc

Hgt Wgt Tpsora t t GHz

Te k b) pe p 0 1 2 0.3 0 5 1 0 3 0 6 0 10 0 18 0 36 50P-4 109(43) 1 4(3) 144 30 35 42 50 50 50P-6 152(6) 1 6(3 5) 100 32 40 45 50 0 50

P-8 203(8) 20(4) 30 37 4 0 50 0 50P-12 0 5( 1 2) 2 7(6 0) 36 3 40 45 0 0 0 0

P1 8 457( 1 8) 4 12) 16 0 7 40 4 0 0 0 >4

P24 61(24) 7 7( 17) 9 0 35 40 45 0 0 0 0 >4

P-36 9 1 4(36) 109(24) 4 35 37 42 50 50 0 0 0 >45

P-48 121 9(48) 17(38) 2 28 35 40 0 0 50 0 0 >4

P-72 1 829(72) 23(0) 3 40 45 50 0 0 0 0 >45o: B mo r .6 mZ( ) Powr rating is .8 / /o mainteace Tis is spciall tu in te v icini t o doos and ot igtaic aeas

Foam asos a gnall nstall d usng pssusns tiv adsivs Thcam sac is ist pantd with th adsive and thn t ack o t aso is coatd Te adsiv is l to as o ad thn th lock is applid tot suace eveal adsive poducts o th makt a usd in ths tps o insallatons t i s st to us th adhsivs commndd th aso manactu caus th hav conimd th compalt o th adhsiv wth thecmist o te aso matial not popl applid, t adhsivs tnd to

los thi onding pow and t pamids stat to com loos om t walls adspcially t cilig

igue 3.1 Gomet o t standad pamid aso (Photogap coutso Advancd lctoMagtcs , nc at CA )



LTRMT BSRB MTRS

ige 32 Geomet of the twsted pamd asoe (Photogaph coutes oAdaced lectoMagetcs, c , atee, CA )

m ie 33 tack f twsted pada ae



2 M R BRB ML 16

0

, "

--

.

'

: ' i ; 5 . . .

!

8

-

I

) 2 ..... f . ;

:

;

;

c+"

f-J

+ 7

2

ige 34 omal icidece eectivit peomace o pamidal abobe

amidal electomagetic peomace i peciied a eectivit at omalicidece ad i tated i d. Geeall, thi imaio i povided i table o

abobe thice veu euec (ee Table ) ove the decibel age o0 to 0 Whe the l oadig i optimized ad the mteial i o the ode o oewavelegth thick, the eectivit i about d. At eight wavelegth, the eecivit i o the ode o 5 d The ume i the mauactue' cha aeoded o o coveece i pecig the podct ige ow tpicalprornc o pyrl trls Th slop o th cr s proxtly pe octave, he ame a a eect file t i alo the ame lo that i expeice i f pace a wave fo wh he itace o feuec i oule Whe te aboe i le the oe wavelegth thick, te peomace ollo a appoache 0 ve uickl Wh the aoe i thick ad lage i

trs o wavlgt, th icet wav ront egi to ca ad he aoeeectivity peomace dop o. The actual dopo i a uctio o the apectatio (heightbae dimeio) ad the atue o the codtive ladig ed ithe poduct to achieve te micowave lo popeie. xpeiece ha hw thatte cve i igue i hieved we the codctivt o e cabo loadig ioptimal. the codctivi i too geat (i e ., the cabo loadig i high), he heeectivit dop at the lw ed o te cuve ad peak at the highe thiceea how i Figue the loadig i too light, te the whole cve hit to

*he curve as deveoped b the author rom pubsed asorbr perfora aes Thecurve has been vaidted i n ma easurements of pramda absorbr maeras



2 LRM BSRB MTERS

-

54 " . . . Over Load ing 48

2 36

, . : ; . . - , _ o k: - - -,

30 , 1t , -- 24

1 8

i , -

l

-

2

f ' 06

;

-

_

0 0 1

0

0Thickness i n Wavelengths

igue 3.5 ect o cbo lodig vitios i th pomce o pmidlbsoes

the ght t takes a thicke mteil o chieve th sme peomace hus, t isst o cool oe o ml s es ocedu a cecs eeciv o h asob whe o e od o o wvelegh hck Aohe impott popety o the lcomge pomace s he eecv y wd gls o cdece his ecly mott o detm g the owdscttg peomace i coc chmes The idst hs developed gph Fg 3 . *) o sc so poc whe h agle o cdes ploted vss he so kss i wvelgth i v commo o hespect io legtidth o echoc chmbe to cse the agle o icidece o the wave ot to ll o the 60 o 0degee ge As c be s, the

bsobe pomace dops o ve pidl vesus gle o cdec , llustaedi gue gue 6 s sd clcultig the lvel o eected eeg thtwll be oud the tes go o th hmb du to ecios om the sidewlls, ceilg, d oo

A couple o bsob dsig impovts hve ecetl be epoted , 8 ] The st o these impoves the loweqc peomce d is cl led the doy podc vd o yl il i c c b ohe pyamid is xtedd o ohl h lgth o the it d the cvs

ee dcuon on bttc efonce n efence



Peroancein B YusAgl ofIncen

2 MCROWVE BORB MER

r

30

O

L

-

-

.

01

0 \(

Thnen Waveng

ige 3 Widag bitatic) pmac pyamida abb

it a hp pit t th top This povid m vm o th lossy mati a giv hight th a pmac i xtdd dw i qcy ctivly dcig th hight a giv qucy bad Two vis w dpd Th it a m 0 i) high ad pat dw t 00 MH ad thcd i 60 i) high ad pat dw t 00 MH Th pmac th 0m (0i ) dsig i compad t a tadd 8m (i ) pyamid iig 8 Th scd impvmt was achivd by sig a Chychv ditit whi t yamid w vaid i gth t ak p th pidic



LTROM BORN MTRS60

50

40. 30 20

1 0

0

"

20 30 40 0 0 70 8 9Agle of Ic idence

F 3 Wd f f wvt tck aso

03

_

Standard 1 .8mPyramid

- New 1 .0m Pyramid

0

. . :. .

. . /

: , \ I ' \ 1 - : . . .1 . . . . : 0.

Frequecy (GHz)

F 38 Pfm s f stdd 8 t 0m doul odc cuved amidal s



MR BRB MR 5

gemet o he mids. his dom hsig o the amids added othe 0 dB o eectio peomce comaed to stadad mid o he smeheight. he Chechev desig has ee aled to oth the tadad ad the doul peidic cuved pymdl mtel, wih excell en eults oh cases. he

tdeo is educed midl heigh o iceaed cos o mauacue o a givepeomce level oml icidece . Aalss hs show tha he Checheveducio acto decees wth isttic gle o ic idece due to the hiig eecive size. he cocet is et suited o eoml cdece 8 .

3 oo rmi oe wo os o hollow amidl aoe ae avalale. he most commo is oduct made ag th atsheets o oam aoe ad wapig hem aoud a suae o oud l ghweighcoe tha has he pamidal geome. Boh mullae ad glelae om haee used to om this te o oduc. he iddual coes ae gouped io

0. 6 m () suaes o commo se o me up coeie u o chame isall atio. he height o th asoe is mla to tha o the sold pamdl soe. hi oduct has ee extevel ued uoe.

Aohe om o his des ig i s a oduc ha made spag laicilm wih a thi metlli c mateal, whch i s he oded to pamdal oam supos. his desig is i llustated i Figue . Both apoaches ode good ieedc d lighweight isll ao. hese es o maeal e esecial l usel o opeio elow GHz, whee he amidal mteals must e log ilegth to povide good eomce dow to 0 MHz.

22 Wege Absbe

Aothe om o the om soe is wedge mteil. his oduct ha he samegeomet s the midl meil i oe dieco d ha u om shae i theohe, il lustated Fgue 0 is used i chame deg whee i s desle t ve te eey ded n a emiati wall sc a i apeed cmes d i compct ges desged o C measuemets. he eectvit isthe sme s the mdl mateial o the same heght, whee the elecic ield ispeedicul to the wedes ad aout 0 dB less whe copolaized wth he diecti o the wedges (whe he aobe o he ode o eight waveleghs

thic). he ew doule cuvaue ad Chechev desgs hae alo ee appledto the wedge asoe wih simla mpoveme lweing the euec o oetio o a g iven thcess o matel A aplcao o hese mateal s descied i he sectio o the taeed chame.

.2.3 Cvote Miowve oe

Aohe bodbd micowve e is mde ug cled e Fgue . ) h mauacg eche s ed he e d ad oud eal ue i he micowae dus he poduc ll alale ad



6 LTROMA ABSORB MATRALS

n , , ,

,,,,,

,

i

M F M-

)

'

_ _ _ _ _ _ _ _ _ _ _ _ ige 3.9 Ctucti f mtl film

ige 3 .0 Gomty wdgshpd s mtil (Phtgph cutsy Advncd lectMgtics, nc t CA



MROWAVE ABSORB MATRALS

ge 3. ry f t c rr (trp cry f c EcrMic Ic St C

c i ri r (icnese) I is primiy ufu i te uppe i-coe fequecy nges, eseciy i te i imete ds xme f tepc i ti pfnce i i i T 3 2 1

3.2.4 cc s

Muti yr i cric e i frm fr f ifr r f Tyr ic cr i y i r icn f t

prc A fiy f prc i rt i T 3 3 s i Ty rydpi n i fqcy cr T tic t pruc t r frqucy f prtio f t mti i utrte i Fi 3 1 2 Tiprc i in y rtry pp ictin T try cii pr-ti di f e ys f rer c f i Rf 4

25 D ecc se

Myr r ry ic r f prii ii f r % r icr r pyr rr f

Type

C \

C3C

be 32 Tyi efmce f Cuted Mice rer

Height,Normal Incidnce Prformanc GHz

Power Raing,c ( . 3 6 \ 3 W/c2 (Wi)

3 \ 3 3 63 3

1 3 35 45 Base dimensions are m"



ELECTROMAGNETC ASOR NG MATERAS

b 33 p y rMu

egRge Bs Poer oml

Tye Frequecy Covere Reec y See Se Tcess kgm b

A 0 H K % 6 1 e m x 6 1 e 06 em 4 0 0 1 bove 4 A73 7.5 H X Ku K % 6 1 em x 6 1 em 1 0 em 8 1 0 0 boe x

A74 35 GH C A 8 X % 6 e x 6 1 em 1 9 e 4 03 oe Ku K 4

A7 4 GH S, C A 8 X % 6 e m x 6 em 9 m 05 bove Ku K 4

A77 1 GH S C A 8 % 6 e x 6 1 em 7 em 09 d oe X Ku K 4 4

A7 06 H S C A 8 X % 6 1 e m x 6 em 4 e 0nd bove u K UHF 4 in

m ic T comiio of o pproc i i mki ofqcy or for ppicio o GHz T ictic hybicoi of pymi fr mi prpry o mc cci y of i cic yr T pymi r proi r pr fot fc im-pc mc pi ry o cciy i ic ric y o m-i Ti c ry iip i i r c i ii

2

-

-

-

8

20

2 -

! _ + - __

" - - - - - -- j - - -

24

0

3

0

00 F 32 fmc c o m i y o



2 MRA AR MARAL 9

Fige 3 .3 Geome o hd delecc aoe Phoogaph coue oAdvaced lecoMagecs, c ., aee, CA.)

pato tha hgh os a low eueces ca e acheved Due o he lage uaeae o he poduc (Fgue . ) , pem he maeal o e eal ace oeo op o aoh Tale .4 povde typcal peomce o h poduc Tpcal peomace ceae a omal cdece ae 3 d, ad 1 d awde age , whe compaed o a pamda aoe o he ame hegh.

.2.6 kw

oadad walwa aoe mauacued placg el exguhg po ltee coe a elocg pae ove he op o a dd pamdl o T e oed w e dety oyee mate Ts cotucto s llusaed Fgue . 4 Typc mecaca ad electcalspecicato ae gve Tale 4.

Tble 3.4 Peomace Data o he yd Dlecc Aoe

Hgtpa borbr rora a ora d MHz

p 0 00 0 00 00

PEM 03 4 9 9 6 3

P8EM 0468 3 6 9 3PEM 064 4 8 1 4 6 32 38

P36EM 0936 6 1 3 0 36 4

P-48EM 1 48 9 16 34 39 44 Above 000 MHz the pefoance o fth e EM seies i s essentiay th e same as te standad yaidal ma-teia The base dimensions ae 06 2 (4 in.2)



ELECROMEC BSORB MATERALS

igue 3 .4 Geomety of ky sore (otoph Courtesy of -nce ectoMnetics Inc Sntee C)

. OW-REQUENC ABSORBING MAERIAL

..1 Itoutio

Te e emn for estin in 3 o 1 MH fequency ne hsrout out the eeopment of sries of mteris optimie fo this ppic-tion The most common mteri is ferrite ti e Ferrite tie s een use fo o-fequency ppictions for oer 4 yers Te increse in shiee encosues e-eope oume mket for he mteri Seer sources n poucts re noie

The tie use fo inin ncoc crs ce in t eomeies Te mosc is crmic i 6 c 00 T r rs in e orm o cs crc r ry r r er rrof i tic A ner r r rr c ic T eri i s ery hey s ry i p y pne ce s of the siee encosur T e r f e nst tn con-siey rete thn f f n in s is t inst ions rexremey fireren sp fr pprin sysem cn s

able 3.5 Typic Spec fcis fr e Wky soer

Tckess od RnReecvy Pefomnce ol Incdence Hz

Type cm n k/m lb/ 05 050 0 0 0 10 0 5 0 00

- 10(5 5) 15 (00 0 5 0 5 40 (5) 1 5 00 0 7 5 0 0 0-1 ( 1 5 1 5 (00 0 0 5 40 40 40-1 5 1 5 ) 0 00 0 5 0 35 40 40 40- 1 0( 5 ) 0 (00) 0 5 0 35 40 40 40 40o Powr raing s 008 was/m0 5 wa/ Ba mnio ar 06 \ m



LOWREUENY ABSORBN MATERAL 41 pct ecty itc i fqncy dptti f ife

qcy i T epc ity i nycm i mti ic t 15 Of ii ctcti cncti cutcte S bobe now be e n ow-eenc c

[ 1 5] It i c pct t c ce it i cti T pt f t ce c tt t ic int t ecti t e 1 8 t f pe t mtin i i ttte yt 2 in i ci y ti me c iti t c ttin t t Typic nit te d f 1 m (2 ) t 3 (1 ft) i T pct i f mti tt ett it fitt cmic W t CCS i tpp itpyi ti t pfc i c trut t n fpeti i pciy i xti t pfmce p it t mic n 1]

. 2

Fit iutt i Fi 315 pie tti t te titi e fmtype ti Ty e cm n c t fi Feit ieety imm t fi umiity cic Ty pi i cmpct ti f ttnutinpe cti i i c i t 3 t 1 MH fqecy

T ic pyic f pti f y p ctmtic i

t fmt ccpt epict i Fi 3 1 W n ct

igur 3 .1 5 Ft fit ti i i i 1 m uit



2 LTROMA ASOR MARALS

X i

'

;

/

' I

r Transmied fReflcted + wve Iw H 0MW

.W

l/

ff" In n I h;

ae H Meu

2

Fg 3 T pyic f pr frrit ti prti

tic tr tru fr pc cutr it mdium (t Z = )t i rct trmitt /r r I t i t miu f tct i tt i f itrt i cic cmr Fr fit ti ttic i jutd tt t rti p f t rct xiti cc t rm r rt c r c in pps p u i t rtur p Ti c i cti f tfqucypdt ctic prpertis f th feit mtri uc s retpmiity d pmiii tht ntct t etermi the eectin c-icit impdc Z d rtur () 7

Fr mt chmr ppicti ice er ith my b e-quired O mthd t mut th ti er ieectc spc (ypcay d)f riu ticn W bt tie pc thices i ptimize the fe

qucy p i she upard t impe te ighfequecy espne hepefmnc f it di r h i Fiue 5 7 8] I chamb dei t iden pfac f sb i mptnt Ti is i ustated ffrit ti i Figur 5 8

T e s is a ctn f the ga e tie Mst es ae reci s mached t 5i teac urfaces Ca mut b ten t nimiz ap bt tie i t ctu itti Mst frrit tie cme i mm uits t t urc pri uit i 2mm uit th educt p pm i ificty



0

-5

10

-15

-0

-

-30

-35

-40

45

-50 0

RQ BRB R

Typical Retur Loss wth Dieecric Spacer

.S4mm

'

. 3mm

I

y0

1

j

'

00Frequency (MHz

igue 3 , 1 7 frit te pfomnce

0000

Fete gd soes e cemc cstng, shon n gu The ife-t itefce odes the fequency esponse of the sobe ut eques themtei to thick to chie the m pfomce s the soid fet mtei-

t is so more tot to gp et th ti s th the soid mti Typicpfomce of the gid tie sores s ho i Fgue 0 8 .Th sod d gd fit tie soes he een successfuy usd in 3m

iI

0

5

10

5

20

25

035

401 0 '

-

o

V

V

/

'\

1 0 0

.

10

igue 3 .1 8 Wideng pefomc of p fete t



ELECTROMAGNETC ASORNG MATEALS

igue 39 Geomet of feie i oe (hotoph coue ofnhie Inc Nok CT

ch f emio ui e e 3 1 MH feuecn

333 Hid Asorers

c eecc e n fom Oe of e m i ue me comntion i of feiei e n o fom e Te oe h in Fiue 3 Nom ici ence pfmc i icu iu 3 [ Th i f e poie c e u 30 M e 8 echc c u MC c upp e cuom ei e ei fo cume ee Cnc h iou mtei uppie i ecommne shou nee exit fo thi type of chme ein The fiue ue e nom incience pefmnce of ome ofhe mei ie fom nume f ufcue Thee oe heeen found o poie oo fonce n eion meuement cm-e

34 ABSORBR ODING

ecen e nce he en of feuenc etin i necho ic chme th ecoe ce to eep cpue moe f oin mtei e



4 ASORER MOELN G

40-

t t

B

t t

i 32 Tic efoce of feite id soe

p os ocu or e oe ry o Cooro our Te eop o o u rcto o eecro-c u rry o o e or pyr coe o to o-rcy r pro o t r copr o t

e eorc oe oe u o o ooeoTi eces te rsese eiodic stuce it sese uifoediu ossessn a cetain (ee isotoic) eectie emttiit andeeiit eae eectio fom suc stuces c te e odeed us-i eo tecniques fo oedimesio iomoeeous edi Ric-cti equtio for te eectio coeiciet is used i ti s o Tis ode i s a-opie fo use it soe foud i ecoic caes used foeectoaetic comatiiity ad eectoaetic itefeece (EMCEMI)esueets oer te feuec e of 31 MH Tei oc



6 LCROMANC ASORN G MATRAS

ige 32 Ferrite/Diectric yri orer eometry [otorph courteyof MC Test ystem (T) uti TX]

tt eut re deti i R 2 2 Tei or h to e ine of hyi ore ued i C test fci iti 22

. A TTNG

t i ity importt tt ori mteri e cpe of ei meure piorto ittio ecoic cmer Te mteri re expeie the itatio aor cot r ry i Te iustry tr h een the use ofhat is knon s the rc [2] Thi consist of pir of hon ocated at nearno incidence nd focuse tord ate e size o f te sobe sae as

iustted in igue 323 he pt is used s efeence The sobe is tenpaced upon the pte te ierece i te recei ina is te eectiityof the soe Tis orks ry fo finite size smpes up to out

( 1 2 ft) At the o frquecie it i ot prctic Waeuide nd ectngucoxia tecniques re us do to the 3MHz frequecy rne Tese techique re discuse in Ref 23

t i i recommee tt ectric ori mter e % testepior to deiey noted in the ctio o soer pefomnce it is impotnttht the tet e efore hen te mtri i on the ore of aeeh hick



RR 7

O

r

'\ \ .r

L

I

igue 3. Pomc o vous mgclcc hd os s o dvcd lcomgc c, C s o Cumg cowvCop, d s o lcomgc s sms ()

micowv mtil s mp lots t yid i mt soud b tstd t su ht m ms t publshd spc ctos

I ddio t pomc sig, it s so cs to coduct m s s

tac tstig vity ts tsts v vv y vwd i Cp

RRN

A aem e a , Mo morin Ts of rhan oam s in nchoicChamrs R Repr 9

. H mer, l ermage Wae Abbe a Ae amb ge Yea, IEEE Transacions on nnnas an paaion l . , p , ly 97



LRM BSRB MTRLS

B. awence necc Caers s n esen onorm. . . 4 pp.5 56 pl .

4 . Kal ineering Eleromagnei ompaibili. n etn I Pessew Y .

5 . Kges necc Cabe w as ly eable 3 D aan Paten Measeent Syse f Weless Cncan nenas Anenna Mearemenehniqe Aoiaion Peeing. p. 3 1 .

6. Teccal Data Seet Pymial Aborbe Cng Mcwae.

7. I. pta et a. Desgn an esng f New Ce Pyaal bsbe AnennaMearemen ehniqe Aoaion Peeding. p. 5 7.

. R. a et a. Cebyce Mltleel Desgn Cncept raaion o f Anenna and Propaaion. l. P45 p 6 gst 7.

. Teccal Data Sheet Hollow Pymidal Aborbe anna

0. Tecncal Data Seet onvole Aborbe dance lectMagnetcs Inc.

1 1 Techncal Data SeeA Aborbe ersn an Cngs.1 . tt et a. aa Css Sectn rec Hse Bstn p. 47 1 5 .

13 Tecncal Daa Seet EM Aborbe vanced le crManecs Inc.

14. Teccal Dat Seet Walkwa Aborbe vance lectMagnetcs Inc.

1 . Paen N. 3 1 78 Mac 10 1 4 onuive ellar rre Aborbe

1 6. Teccal Data Sheet Aborbing Maerial M 0.

1 7. Techncal Data Seet ae Cpin.

. Tecn cal Data See t Ty Cprtn .

. Tecncal Data Shee MC Tes Systes

E. Keste an C. Hl lway weency Mdel f Wee Pyabsbe aysI: ey ranaion on Eleromagnei ompaibili. l. 36. 4 p. 3 ebe 1 4

1 . C. . Hllway an E. ueer reuency Me f ee yasrbe ays Cpe n Measue ess naon on ema-ne ompabi. l. 3 . 4 p 3 ee 4.

. C. . Hllway e a. Cpaisn f lecagnetc bsbe Use n neccan Seanecc Cabes f ssns an ny Tesng f Dgtal Deces E ranaion on leromane ompabli l . 3 N. pp .337 eay 1 7.

3 . I : 9E recened pactce fr afeency R absbe

ealatn n te ange MH t 5 H.



CHAPTER

TH HAB LOSU

4.1 NTRODUTON

Sii r ic fcti fir pri irfrc cpri cric rppi T yp f i i rir i cif prp r f uip i Hiprfrc ii i rquir r ii ip prtct fr ry i

pr rr y r ii y rir t ctr cric ir iti cic cr *T ii f cic t fci iti c riy f fr T yp f

i di rqir i fcti f t tr f tt rqir If i i pririy i rci ci fr cic tri i t i ry it qt If i i pri TEMEST

ir fr qipt f t fciiy r rt iiy y rquird If it i t ipr quip r t ctrtic cptiiity f ircr t cur i pry rquirT rir f i cptr i pri rif ri f typ f cr cy u cic t fciiti Tr r iiti itc typ pi t typ f prfrc rquir t t f ric xpct T rfrc prid ti ri f t riu ctructi

* A complete tement on sheded encloses s vlble n the book cc cgc g H urthe nfomton s vlb e n Refs nd 3 s tem eted to the contro o fems sons fom compter equpmen pocessng cssfed nfomon



50 H HMBR LOSR

4.2 LCMGN IC N NC

op coto of cocti rit itrfc c c the abitois tt c itrfr it t srts bi couct i th cha

4. L T

ity of shi co srs c s to coto t tsti iotTh te ost coo th sht ta i prfabicte, e -coss Shii tis cooy s i th costrctio of shie coss cosist of t fooi

yoo/prticor p it o o o both sies ith aiousas of i st t cooy us fo pfabicate cosrs Othr ts, ch s copp foi o sc, a so fabicated in asi r

2 Vios thices of st t d ito pac o a stee suppoti stuctur

3 i foi is ist it cotact ahsi, o oisoofstrock, hich s iu foi bo to oe fac of the boa is use

4 Copr foi ith pp bcki hich i s ista ith cotact ahese o oo coppr ti ista i ik ca fo a sine

si syst5 Copp scri is t to oo stus spot soee

6 e e e e s , resutn n sne-shi syst

coitio f th is s for spciiz appicatios

ry, t basi c sii ctiss of th shi i ata i s aeqt fo ost ppictios xcpt i th cs of hih poe equeents oTEMEST Spci tchiqs st ppi to t tse quieets

Th ss oors of si c os ay st the pefoanc of a

i cosr

4.4 LCMGC LD N

44.1 Inroducon

s ot pros y, th ios fors of ctoetic shii neay faito th css s, prfrict, o chitcta Th att fo consi stsof shi i tht is it it t rt trctr



4.4.2 Te Weded Sed

44 LR H 1

The welded seam s he mos reliable Various welded seams are llsrated in Fig-ure 4 t s also he ost expensie The seel must ae a mini hiness,usuall gage or ter, and mus t be eldweled onnous etal nertgas (G) weld s be ade along eer sea T wed t b watertighto pinhoe ae peed Wth te aid o f sea a deetos deeoped fo tting seas, tight wed ae otie aiee b te eding dt Wel-onstted welded enoses a poide oe 0 dB of sedig eenesthogout he entie feen spetru ided eosres ae bidingswin a biding, and the sield ing i s no depedt on the pe of ostionsed for the exerior of te fail i

The onsrion of welded enlosures is not a new teology an fail itieshae been bul t o onte eleroagei heat o onto esions The eso a sessl enlosure are to design fo onstutabl it, speiiations with n-ambguous perforane reuireents, goodali ontol poisions, well-ualied welders, and propel trained quait ontrol inspeors 4 reas re-uiring patiuary lose atenion in lde he o lowing

F e esg Bklig of he oo sid de o ea aied dghe sam welding po as been he singe ae onsion dii in an proets nnoatie appoaes to aoid tis poble are dis-ssed in 4

e es. The designer should arefl detail a orne sea, pati-ularl where hree shied srfaes o in The designer s ense tat aess

s aailable o omplete weld a hese loations I-cess W sg. n ae nproess weldtesing pogra is ab-

soluel neessa drg shield assembl o aoid sstea proedralmisakes, whih ould lead o osl repairs laer

aret o weld ehnues ae used n sheld onsruion, and eahshod be reiewed pror o designng a welded insallaion oplee dsus-son o he arious ehnques is aailable n reerenes , 4

e Cl pe e or Peice e

Te mos ommo shed seam s he l amped sea O these, most anaurersof shielded enlosres use the geoer ilstrated in Fige . e desig isal ed has and as The part that is used to hod nts o is srewed ito is i tefo of a ha hannel , whereas he ineior sapping is at, wit oe pag fore ea sews sed hese insaaio W e ieding oed obo sde of e p lwood o paboad pa, sdg s ara oe 00 dB hroug 1 8 Gz his sse is apa o opeaio p o 0Gz, wit pop ateio to doo and ens A oed isa lao a-ed in Figure 3 . Compee deai s on this for of sieding ae deaed in ef .



52 THE CHAMBER ENCLOSURE

; 7-

Stel Tub ingBack .

Strucre (Embede

StuctrSubf loor

a)

W ea n g S a b

(b

i Concret Slab)

SteelSh e l d n g

56 i n .Typcal

Figure 4.1 Selection of welded seam (a) Mehod of plug welds and bacup

stuce use n oos, cei ling and wa s. (b) A method of using pa-li ke panels

to fo the oo in a shieded ecosure



4.4 ELECTROMAGNETIC SHI ELDING 5

Floor Seam-Typical Insde Shelded Roo

Wa Sea pca nsde eded Roo

Emegency LigtsOuet Box

Eectca Ouleto Doo

Patform

Figure 4.2 The clamped seam.

Emegec

gt

F oor

G oun tu

Extacto Fan

igue 4.3 The prefabricated sielded enclosure.



HE HMER ENLSRE4.4.4 T gll m

hee ae a aey of mehods used o aompsh sngeshed syses hemos omon s o use ondue ape oe he seas e bes eod s o aphe sedng maea and hen ape he ons Te goa s a meaomea seahroughou he whoe enosue n a popery desged syse, s edg ee-eness on he orde of dB up hough Gz an be obaned Generaspeakng, hs form s a ed arheura shedng, n a e sed ng s bu no he sruue of he ex sng ud ng arge are of ehues ae beendeeoped o aompsh hs ype of shedng

4.5 PNTRATN

Fna y, a she ded enosure s ony as good as he meod used o brg he a-ous sees no he enosure Pesonne and eupmen en, powe, en a-on and heag, ghpressue ar, fre sprers, daa and ono nes eaeure speazed means of peneang a sheded enosue Tey mus bepopery desgned and mpemeed o ensure ha pope shedng eeeesss aeed n e fna nsaaon he eferenes pode gudane on e de-sg of suh peneaons e sheded door s e mos a o f a e pee-aons Vaous fos of he doo ae usaed n Fge 4 4 ese ae pre -so eeoagnemehana dees a s be desgne nsaed, andmananed w exree are peas desgns maybe reured for aeo

habes, espeay hose ha use fere, eause s use ma doube ewegh of he door

4.6 E ANCE VEIFICAT

s reomended ha he shedng eeeess of a sheded enosure e er-fed before aepng he ompeed fa and por o e nsaao of ananeho aeras andard es proedures exs wh an e spe fed for spupose 5

4. 7 HIDD ENUR GRUN DNG

Groundng of a sh eded enosue shoud no be a homss knd of endeaor, 7 Cosderaon mus be gen o eera safey, sgna onro, and, nsome ases, sgna seur ga seur s goerned b he arous seuragenes, whose spefaons shoud e onsued pror o onsron of anype of fa y ha w be proessng assfed foaon



Gasket

Door Fme

Hinge

4.8 FIRE PROTECTION 55

andle inCsed Pson

Suace atch(Two Poin t}

Do Elevation

,

Doo n RF Shededad Clsed sio

Removable onac inges

_ - r:-- , ' I I' r, \ I

\ \

\ I I \

- - - -

J L_l r

C_-

-

Figure 4.4 Common shielded doo ssems

4.8 FIRE PROTECTION

Te fie protctio reqirt are pecied by rr of te bidg wc t cabr b cat a by ca r a T vr- ar geray . ( 1 ) Sprinkler systems: I ga, rab aprklr a b r a acc cab cau y bcource rctd rgy cay adar crc tt ac Ocoo vro tcc y a a ca rr aa



TE AMER ENSRE

that ae designed to pop down when chaged with wate pon the atiation of asmoke deteto within the hambe These ae geneay set p to be dy piedsystems Unfotnaey, the histoy of these sys tems has been poo, ease ai denta di shage o these type o wate systems hae ased me damage than

ies, ew f whh hae oed snce the adent o the 0 amaiityeqieents n he asoes at ke age spnges and ae vey tto dy ot i soaked y wate f standad spinke systems mst e sed, thencae shod e taken to minmie he eect o eectons m the standppes yoating them o the hame as the ceiing of the hame ecenty, somesppes ave een sing enoic pipe i ie of the noma ak ppe, espeay in MC hambes (2) Gs ischrge syses: nmbe of Halon sbstitteshave been deeloped which smothe ies bt do not damage the eipment in thechambe C has een sed n vehce test chambes, bt cae mst e taken nthe design o the fie poteton system so that pesonne ae not aght in the

chame when the gas is dshaged () Ce ome aiity manageshave detemined that it s est to isoate the faciity behind twoho fieatedwas and not se any fie potection eqipment ecept eaoate smoke detectsstems wthn the chame e ecent shiee nstaaons hae sed spnkes aove the hame to enhance the containmen

Becase chame fies geneae a geat dea of smoke, it i s eommended hatsmke inhaan eqien e ainaned at a e stan imeae sdethe chame aess do s eipent is eseay eqie a e nto system has een instaed n the chame he aea mst be heked po tomanay atiating the system to ense that no pesonne ae sti inside the

chambe

L H Heg, hua ag Shg ak, EEE e, Nek, 1

. M, Gug a Sg hqu n Wey & Ss, Ne k,1.

3 . L. eecc, h Dsig Shi lu Bttewt-He iea, Wb,

MA, 4 US ando for h Dsig a nuin f EMP/EMPE hildd a-ilii A Regial iil Egiee etal Reg, Dalla, X, 9 7

5 EEE St 9 , adad Mh fo auing h Einss oEl-romagni hiding nlosu EEE Pe Ne Y, 99

6 . Riley, Eia udig Bigig ouding Ba o Eah 6t eiti,Dela Pbl ig, Albay, NY,

7 . EEE St 1 1 001 , EEE Rd Pai Pwng a Gug Equ EEE es Ne k 1



HA

AN ECOIC CA BEDGN C Q

5 IRODIO

The design of micowave anechoic chambes (aangement of absobe mateiason te inside sfaces of a cambe encose) egan gey emicy in te150s. As the concets became moe pactica, commeciy deveed higpefomance anechoic absobes became avaiabe in the 10s, aong with en

hanced peforance. t was then possibe to des ign chambes sing geometicaoptics (O) techniqs, aso own as ay tacing This has ed to a vaiety ofstandad chabe designs that ae commony avaiabe fom abot a doen chamr crr r r c c crhas evoved The deand fo indoo easeents at ow feqencis (31 e rryr e cer T, r, reqr r re ecq rer pe e perrc

5.2 PRACTICAL DESIGN PROED RES

5.2. Introduction

Te fo oing factors ned to be consideed the des ign of an anechoic chambeabsorbr ayot

a ype of easeents to be peford

reqency of opeation

5



E MBE DES TEES

c Foo sce vie

Hegh of he sce vie

e eomey of he chme

f eho of ccece esigg Cos

5.2.2 Quick Estimate o Chamber Peormance

T demnstte the most common meh f esigning micowve nechicchmbe, ssme genepose echoic tes fiity f mesing smpete ntenns yic tenns wod be sm hns, spis gpeididipe ys PDA), sios enns ove he to H eenybnd

Fthe ssme th he chme i be 3 0 m 0 ) wide, 3 m ( ) high,nd m 0 ) ong The ge egh wi be n he e of m ( ) s indicted in Fige 5 The feesce VW pocede wi be sed t pemthe chmbe ccece es Cns Che fo omee ei s of the Feece VWR ocee ) Fige 5 eics vious ems ivoved in simeytcig design The esig meho s ee o he pocees sed es thechmbe When chme is ese, fie obe i s fis n nsvesey cssthe chme nd thogh he cete o he est egin s shwn in Fige 5 sine n ode fo the obe o eec soce o eneos enegy, it msthge its hse ih esec to he iec h he cse of the tsvese

oe oy eegy eece o he sies wi be eece becse ohesfces e e ih he moveme of he oe Thus e ee o y consiethe eegy eecte fom hese sufces o eemine he moun of eecte ey a acs s ion a s sfacs T o a s cosiee s h ecvi of he souce e becuse he eve f iui

3 m

k

/

m

igu 5.1 A i usio of sim e ycing esig



1 7

.M

-5!" 6.S

] -8 .33

E

0p

6 7

3 3

1 o

5.2 PRACTICAL DESIGN PROCEDURES 59

5

r

i

,

\

\

1

1 0 5 20 25 30 35 40 5PHIiAngl of pk o ate i degrsFigure 5.2 Chart of pattern eve s of a horn antenna

ton on the sdewas is a ncton of the ange o the main beam of the source an-tenna For the geometry assume, ths woud mean that the atte leve at 32 de-grees o the man beam woud be the evel illuminating he sidewall surfaceso he pon o reecton I one ame tha the nenna ben use s asource horn antenna with a 28 degree halfower bamidth, then the attern lev-e woud be on the order of 1 0 dB, as indicated in igure 2 The ange of inci-dence t the idewall absorber s 58 (90 32) degrees Assume that we requre theextraneos sgnal leve to be a mnmum of 0 B at 2 GHz. Then the sewa

absorber mut be 40 10 or 30 dB at a wavelength o 1 5 cm (5 9 inches) Fro

anechoic chambers a fundamental design and specification guide

Documents

fundamental design

s roucion1

s cotts

specification guidehttp

ponsoremcs liaison

kirkm s newmnm

s press445 oes lane

barssd o pissio