tc 382 antenna and microwave

8/9/2019 TC 382 Antenna and Microwave

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Antenna & Microwave Engineering_NED University of Engineering & Technology- Department of ElectronicEngineering

PRACTICAL WORK BOOK

For Academic Session Spring 2013

Antenna and icro!a"e #ngineering

$TC%3&2'

For

T# $TC'

(ame)

Ro** (+m,er)

Batc-)

.epartment)

/ear)


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Laoratory !or"#oo"

$or the %orseT%-'() Antenna an* Microwave Engineering

Antenna & Microwave Engineering +ractical !or"oo" covers a variety of e,periments

that are *esigne* to ai* st*ents in their profession an* theory The practical are very

eneficial to st*ents an* will help them in having a core "nowle*ge an* n*erstan*ing

of the s.ect The practical covere* in this manal give more than a asic intro*ction to

st*ents

They cover a variety of topics which incl*e antennas/ transmission lines an* microwave

wavegi*es

A practical e,posre to sch e0ipment is necessary as it il*s on the theory taght to

st*ents

The practical are ase* on mo*ern trainers that incorporate a variety of fnctions to

*emonstrate to st*ents the principles of Antenna & Microwave Engineering techni0es

The st*ents will *evelop a profon* interest in this corse which will facilitate them

whether it is in ftre professional wor" or higher st*ies

+repare* #y

$ar2een 30al/ LectrerTelecommnications Engineering Department

4eviewe* #y

Dr 3rfan Ahme*/ Associate +rofessor

Telecommnications Engineering Department

Approve* #y

#oar* of 5t*ies of Department of Electronic Engineering


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I(.#S(O LAB OB#CTI# SI4(AT5R# R#ARKS

1 To investigate the properties a *ipole antenna in freespace

) To st*y the effect of con*ctor thic"ness on an*wi*th

of *ipole

' 6 To investigate the properties of a system comprising a

*ipole an* a parasitic element

6 Un*erstan* the terms 7*riven element8/ 7reflector8/

7*irector8

6 To "now the form of a 9A:3 antenna an* e,amine mlti

element 9agi

6 To see how gain an* *irectivity increase as element

nmers increase

; 6 Un*erstan* the terms 7aying8 an* 7stac"ing8 as applie*to antennas

6 To investigate stac"e* an* aye* 9agi antennas

6 To compare their performance with a single 9agi

< 6 #e familiar with the D35= form of antenna

6 To investigate the gain an* *irectivity of the *ish

antenna

6 Appreciate the a*vantages an* *isa*vantages of a *ish

antenna as compare* with a 9agi

> 6 #e familiar with the Log +erio*ic form of antenna

6 To investigate the gain/ an* *irectivity of the log

+erio*ic antenna over a wi*e fre0ency range

6 Appreciate the a*vantages an* *isa*vantages of a log

perio*ic Antenna as compare* with a 9agi

? 3*entification of *ifferent wavegi*e components

( Determination of 3nsertion loss in a wavegi*e

commnication system


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@ 6 To *escrie the characteristics of the horn antenna

6 To carry ot gain measrements sing metho* of

comparison

1 Measrement of the gain of =B4N Antenna C sing

Metho* of the two antennas

11 #y the se of the slotte* line/

6 To *etermine the n"nown fre0ency

6 To *etermine the oltage 5tan*ing !ave 4atio 5!4F

an* 4eflection %oefficient

1) #y se of slotte* wavegi*e

6 To oserve how the loa* impe*ance affects the 5!4

6 To *etermine when a wavegi*e is properly terminate*

1' To measre n"nown loa* impe*ance attache* to a

wavegi*e sing the smith chart

1; $amiliari2ation with NA ector Networ" Analy2er

$ront panel tor

5etp "eys

Display $ormats an* Diagram Types

aF %artesian Diagram

F +olar DiagramcF 5mith %hart

1< Measrement of 5 parameters of availale filter


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LAB S#SSIO( 01

OB#CT)%To investigate the properties a *ipole antenna in free space

#65IP#(T)%Antenna Lab har*ware

Discovery 5oftware

Dipole elements

9agi oom

T7#OR/)

Antenna) An antenna is a trans*cer *esigne* to transmit or receive ra*io waves which are a class ofelectromagnetic waves 3n other wor*s/ antennas convert ra*io fre0ency electrical crrents into

electromagnetic waves an* vice versa Antennas are se* in systems sch as ra*io an* television

roa*casting/ point-to-point ra*io commnication/ wireless LAN/ ra*ar/ an* space e,ploration Antennas

sally wor" in air or oter space/ t can also e operate* n*er water or even throgh soil an* roc"s at

certain fre0encies for short *istances +hysically/ an antenna is an arrangement of con*ctors that generate

a ra*iating electromagnetic fiel* in response to an applie* alternating voltage an* the associate* alternating

electric crrent/ or can e place* in an electromagnetic fiel* so that the fiel* will in*ce an alternating

crrent in the antenna an* a voltage etween its terminals

Simp*e .ipo*e Antenna).st aot the simplest form of antenna is calle* the *ipole This is a con*ctorthat is *ivi*e* in the mi**le an* is connecte* at this point to a fee*er or fee* lineF This fee*er then

connects the antenna to the receiver/ or transmitter $ee*ers come is many forms +roaly/ the most

commonly se* is coa,ial cale This is the type of fee*er se* in this trainer

:enerally/ the *ipole is consi*ere* to e Bmni-*irectional in the plane perpen*iclar to the a,is of the

antenna/ t it has *eep nlls in the *irections of the a,is


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PR# LAB TASK)

61 Discss Dipole Antenna %haracteristics

$re0ency s Length

4a*iation +attern an* :ain

$ee*er Line

62 !rite %ommon applications of Dipole Antenna

PROC#.5R#)1 3*entify one of the antenna #oom Assemlies an* mont it on top of the :enerator Tower

2 Ensre that all of the elements are remove*/ e,cept for the *ipole3 E,amine the *ipole elementG yo will see that the en*s are e,ten*ile A*.st the *ipole length so that

it is


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LAB S#SSIO( 02

OB#CT)%To st*y the effect of con*ctor thic"ness on an*wi*th of *ipole

#65IP#(T)%Electronica eneta trntaleF with stan*

$iel* meter 5$M 1 E

Microwave generator

?


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#+ipment Set+p

PROC#.5R#)1 %onstrct a *ipole with arms of 'mm *iameter shortF an* mont on the central spport of the

trntale2 5et the antenna an* instrments as shown aove in figre

3 5et the generator to a *eterminate otpt level an* to the center fre0ency of the antenna n*er test

?1< M=2 for measrements with short thic" or thin *ipoleF

8 A*.st the *ipole length an* sensitivity of the meter to otain the ma,imm rea*ing 1 th LED

glowingF

9 Now *ecrease the fre0ency p to the vale sch that the 1th LED "eeps on glowing Note the vale

as f)

: Now increase the fre0ency p to the vale sch that the 1th LED "eeps on glowing Note the vale

as f1

; %alclate the wavelength for the resonance fre0ency of aron* ? M=2 for short *ipole sing the

formla JKcHf& The ratio se* for calclating the shortening coefficient is JH)* where *K*iameter of con*ctor

$rom graph otain a shortening coefficient I %alclate the physical length of Dipole an* compare

with the measre* length

10 +hysical length of half wavelength *ipoleK JH) , I

11 %onstrct a *ipole with arms of (mm *iameter shortF

12 4epeat the same proce*re for thic" *ipole

OBS#RATIO(S CALC5LATIO(S)%4esonant fre0ency K M=2

J K cHf = 300/ = cmMeasre* length of short *ipole thinK ))mm

Measre* length of short thic" *ipoleK1@


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T7ICK dipo*e)

dD

The ratio se* for calclating the shortening coefficient is with a *iameter of (mm

J/2d=K=

$rom graph we otain a coefficient of 08;for thic" *ipole

%alclate* physical length of half wavelength *ipoleK )J, IKThese vales refer to a *ipole in air Actally the *ipole n*er consi*eration is not totally in air

ecase for mechanical reasons/ its internal part is in a *ielectric This slightly increases the resonance

fre0encyF

R#S5LT)


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LAB S#SSIO( 3

OB#CT)%

6 To investigate the properties of a system comprising a *ipole an* a parasitic element

6 Un*erstan* the terms 7*riven element8/ 7reflector8/ 7*irector8

6 To "now the form of a 9A:3 antenna an* e,amine mlti element yagi

6 To see how gain an* *irectivity increase as element nmers increase

#65IP#(T)%Antenna Lab har*ware

Discovery 5oftware

Dipole elements

9agi oom

T7#OR/)%

Antenna)An antenna is a trans*cer *esigne* to transmit or receive ra*io waves which are a class ofelectromagnetic waves 3n other wor*s/ antennas convert ra*io fre0ency electrical crrents into

electromagnetic waves an* vice versa Antennas are se* in systems sch as ra*io an* television

roa*casting/ point-to-point ra*io commnication/ wireless LAN/ ra*ar/ an* space e,ploration Antennas

sally wor" in air or oter space/ t can also e operate* n*er water or even throgh soil an* roc"s at

certain fre0encies for short *istances

+hysically/ an antenna is an arrangement of con*ctors that generate a ra*iating electromagnetic fiel* in

response to an applie* alternating voltage an* the associate* alternating electric crrent/ or can e place* in

an electromagnetic fiel* so that the fiel* will in*ce an alternating crrent in the antenna an* a voltage

etween its terminals

/agi 5da Antenna) An antenna with a *riven element an* one/ or more/ parasitic element is generally

"nown as a yagiO/ after on of its inventors 9agi an* U*aF

!ith the length of the secon* *ipole the n-*riven or EParasiticO elementF shorter then the *riven *ipole

the *riven elementF the *irection of ma,imm ra*iation is from the *riven element towar*s the parasitic

element 3n this case/ the parasitic element is calle* the directorO

!ith the length of the secon* *ipole longer than the *riven *ipole the *irection of ma,imm ra*iation is

from the parasitic element towar*s the *riven element 3n the case/ the parasitic element is calle* the

re?*ector


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PR#%LAB TASKS)

P1!hy *o we re0ire ArraysQ :ive 4easons

P) Discss *ifferent types of Antenna Arrays

P' =ow is #EAM!3DT=/ D34E%T33T9/ :A3N relate*Q

PROC#.5R# OBS#ATIO(S)

1 3*entify one of the 9agi #oom Assemlies an* mont it on top of the :enerator Tower

2 Ensre that all of the elements are remove*/ e,cept for the *ipole

3 Ensre that the Motor Enale switch is off an* then switch on the trainer

8 Lanch signal strength vs angle )D polar graph an* imme*iately switch on the motor enale

9 Ensre that the 4eceiver an* :enerator antennas are aligne* with each other an* that the spacing

etween them is aot one meter: 5et the *ipole length to 1cm

; Ac0ire a new plot at 1


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A..I(4 A S#CO(. R#FL#CTOR)

1 Mont the *riven *ipole on the oom forwar* from the a,is of rotation y aot )


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7o! do t-e gains and directi"ities compare=

81Lanch signal strength vs angle )D polar graph win*ow

82 Ac0ire a new plot at 1


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Antenna & Microwave Engineering NED University of Engineering & Technology- Department of Electronic Engineering

LAB S#SSIO( 8

OB#CT)6 Un*erstan* the terms 7aying8 an* 7stac"ing8 as applie* to antennas

6 To investigate stac"e* an* aye* 9agi antennas6 To compare their performance with a single 9agi

#65IP#(T)Antenna Lab har*ware

Discovery 5oftware

> element log perio*ic antenna

T7#OR/)9agi antennas may e se* si*e-y-si*e/ or one on top of another to give greater gain or *irectivity This is

referre* to as aying/ or stac"ing the antennas/ respectively

PR#%LAB TASK)

61!hich configration of the two appears etter than the other an* whyQ

PROC#.5R# OBS#RATIO(S)

BaGing T!o /agis)

1 %onnecte* p the har*ware ofAntenna Lab.

2 Loa*e* the Discovery software3 Loa*e* the NE%-!in software

8 Ensre that a 9agi #oom Assemly is monte* on the :enerator Tower

9 B+i*ding +p a : e*ement /agi T-e dimensions o? t-is are)

Lengt-$cm' SpacingRe?*ector 11


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.ri"en e*ement 1 Rero referenceF

.irector 1 (< )< cm in front of DE

.irector 2 (< < cm in front of D1

.irector 3 (< < cm in front of D)

.irector 8 (< < cm in front of D'

: +lot the polar response at 1 element 9agi onto the 9agi #ay ase assemly at three holes from the centre Assemle an i*entical > element 9agi on the other 9agi #oom Assemly an* mont this on the

9agi #ay ase assemly at three hole the other si*e of the centre/ ensring that the two 9agis arepointing in the same *irection towar*s the 4eceiver TowerF

10 3*entify the )-!ay %ominer an* the two 1('mm cales11 %onnect the two 1('mm cales to the a*.acent connectors on the %ominer an* their other en*s to

the two > element 9agis

12 %onnect the cale from the :enerator Tower to the remaining connector on the %ominer

13 Ac0ire a new plot for the two aye* antennas onto the same graph as that for the single > element9agi

18 4everse the *riven element on one of the 9agis an* ac0ire a thir* plot

.oes re"ersing t-e dri"en e*ement ma@e m+c- di??erence to t-e po*ar pattern ?or t-e t!o ,aGed

/agis=

7o! does t-e directi"itG o? t-e t!o ,aGed /agis compare !it- t-e sing*e /agi p*ot $!it- t-e

dri"en e*ement t-e correct !aG ro+nd'=

7o! does t-e ?or!ard gain o? t-e t!o ,aGed /agis compare !it- t-e sing*e /agi p*ot $!it- t-e

dri"en e*ement t-e correct !aG ro+nd'=

Now/ move the two 9agis to the oter sets of holes on the 9agi #ay ase assemly Ensre that yo

"eep the *riven elements the same way ron* as yo ha* efore to give the correct phasing5perimpose a plot for this assemly

7o! do t-e directi"itG and ?or!ard gain o? t-e !ider spaced /agis compare !it- t-e c*ose spaced

/agis=

- 1< -


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Stac@ing T!o /agis)

1 3*entify the 9agi 5tac" ase assemly the narrow grey plastic strip with tappe* holesF an* mont

this on the si*e of the :enerator Tower2 Mont the > element 9agi onto the 9agi 5tac" ase assemly at one set of holes aove the centre3 +lot the polar response at 1 element 9agi on the 9agi 5tac" ase assemly at the ppermost set of holes/ensring that the two 9agis are pointing in the same *irection towar*s the 4eceiver TowerF

9 3*entify the )-!ay %ominer an* the two 1('mm coa,ial cales: %onnect the two 1('mm cales to the a*.acent connectors on the %ominer an* their other en*s to

the two > element 9agis; %onnect the cale from the :enerator Tower to the remaining connector on the %ominer

& 5perimpose the polar plot for the two stac"e* antennas onto that for the single > element 9agi 4everse the *riven element on one of the 9agis an* sperimpose a thir* plot

10 %hange the position of the lower 9agi to the ottom set of holes on the 9agi 5tac" ase assemlyEnsre that the *riven elements are correctly phase* an* sperimpose a forth polar plot

7o! does t-e directi"itG o? t-e di??erent con?ig+rations compare=

7o! does t-e ?or!ard gain o? t-e stac@ed /agis compare !it- t-e sing*e /agi=

7o! does t-e ?or!ard gain o? t-e stac@ed /agis c-ange !-en t-e dri"en e*ement p-asing isincorrect=

R#S5LT)

- 1> -


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LAB S#SSIO( 9

OB#CT)6 #e familiar with the D35= form of antenna

6 To investigate the gain an* *irectivity of the *ish antenna6 Appreciate the a*vantages an* *isa*vantages of a *ish antenna as compare* with a 9agi

#65IP#(T)Antenna Lab har*wareDiscovery 5oftware

+araolic Dish reflectorDipole 1cmF

9agi oom:ron* plane reflector

T7#OR/)A *ish can e thoght of as a passive reflector that focses the energy from a sorce into one *irection/ mch

li"e a paraolic mirror focses light =owever/ to perform as efficiently as an optical reflector/ a *ish nee*s to

e in e,cess of ten wavelengths in *iameter for the fre0ency eing se* This is very often not the case in

practice/ *e to physical si2e constraints A horn antenna is often se* to/ lanch or captre energy from a *ishreflector Althogh this is 0ite common/ a simple *ipole is often se* to perform the same tas" The *ish set-

p withAntenna Lab is one that ses a *ipole at/ or close to/ the focs of a >cm paraolic *ish

The *imensions for a *ish are shown in figre The focal length for a paraolic *ish is given y

The gain of a *ish is given y

!here/ 7:8 is the gain/ 7a8 is the area of the *ish/ 7c8 is the *ish efficiency an* 7J8 is the wavelength Note that

this is *#i/ yor measre* gain will e *#i $or the *ish with Antenna Lab at 1


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PR#%LAB TASKS)

P1!hat is +araolaQ !hy its geometry ma"es it sitale to e se* as Antenna 4eflectorQ

P) Descrie *ifferent metho*s of fee*ing +araolic 4eflector


1 %onnect the har*ware ofAntenna Lab s *escrie* in the Bperators Manal

2 Loa* the Discovery software as *escrie* in the Bperators Manal3 Mont the 9agi #oom Assemly on top of the :enerator Tower an* place the *ipole at the centre/

*irectly aove the tower

8 5et the length of the *ipole to 1cm9 Do not connect p the coa,ial cale to the *ipole

: Lanch new signal strength vs angle )D polar graph

; #ecase the *ish is a physically large strctre/ the spee* of rotation of the system mst e lowere* for

this Assignment $rom the men select Tools/ then change/ Motor 5pee* 5elect a vale ofappro,imately > S an* clic" BI

& Now/ connect p the cale +lot the polar response of the *ipole at 1


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1: 5et the plane reflector


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.oes t-e response c-ange signi?icant*G=

23 Try for other *istance an* reflector spacing

Is t-e response o? t-e dis- antenna critica**G dependant on t-e spacingQ

R#S5LT)

- ) -


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LAB S#SSIO( :

OB#CT)

6 #e familiar with the Log +erio*ic form of antenna6 To investigate the gain/ an* *irectivity of the log +erio*ic antenna over a wi*e fre0ency range

6 Appreciate the a*vantages an* *isa*vantages of a log perio*ic Antenna as compare* with a 9agi

#65IP#(T)

Antenna Lab har*wareDiscovery 5oftware

< element log perio*ic AntennaDirectional copler

T7#OR/)

The 9agi antennas that yo have een investigating are inherently narrow-an*wi*th antennas The relatively

small range of fre0encies over which the 5!4 is elow )1 has *emonstrate* this The log perio*ic antenna

is a *esign that attempts to cover a mch wi*er an*wi*th !ith a 9agi all of the elements are active on theoperating fre0ency !ith a log perio*ic antenna only a nmer of the elements will e active on any one

fre0ency/ the actal elements that are active changes as the fre0ency is change* The role of active elementsis passe* from the longer to the shorter elements as the fre0ency increases iew of the assemly re0ire* for

this assignment

Log periodic antenna

- )1 -


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PR#%LAB TASKS)

6!e say that a log-perio*ic antenna L+/ also "nown as a log-perio*ic arrayF is a ,road,and/ mlti-

element/ +nidirectiona*/ narro!%,eam antennathat has impe*ance an* ra*iation characteristics that are

reglarly repetitive as a logarithmic fnction of the e>citation ?re+encG The in*ivi*al components areoften *ipoles/ as in a log-perio*ic *ipole array L+DAF Log-perio*ic antennas are *esigne* to e se*?%

simi*aran* are ths also ?racta* antenna arraGs

Define each of the terms >F in ol* lettersF


1 %onnect p the har*ware of Antenna2 Loa* the Discovery software

3 Mont the 9agi oom assemly on top of the generator tower an* +osition the *ipole at the center/*irectly aove the tower

8 5et the length of the *ipole to 1cm

9 +lot the polar response of the *ipole at 1


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12 4estart an* plot the response for 1 M=2/ 1? M=2 an* 1( M=2 on the 1


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LAB S#SSIO( ;

OB#CT)

3*entification of *ifferent wavegi*e components

#65IP#(T)

!ave-:i*e mo*M!-) 3 mo*M!-'F!:H%BA a*apter mo*M!1F

5lotte* Line mo*M!-


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Wa"e%4+ide $modW%2 I modW%3')

The Vwave-gi*eV is more properly calle* V!: 5traight sectionV 3t is se* as a transmission line an* there arerigi* or fle,ile versions of *ifferent "in*/ that enale the transferring of the electromagnetic fiel* insi*e it

3mportant characteristics are low loss an* 5!4 Br system ses three rigi* an* straight ones with thefollowing characteristics/ $igre '

Fig+re 3

S*otted Line $modW%9' )

3t is a *evice se* to *etect the stan*ing wave insi*e the gi*e Figure 4F The Detector mo*M!-;F mst e

se* an* is screwe* on the pper part of the trailer that sli*es along the slot of the wave-gi*e The voltageprovi*e* y the *etector is proportional to the amplit*e of the stan*ing wave in the *ifferent positions along

the line

Fig+re 8

B(C%SA detector $mod W%8')

3nsi*e/ the *etector is characteri2e* y the following components6 3npt 4$ matching impe*ance D% 4etrn

6 4$ y-pass capacitor

6 Detector *io*e with negative polarityF

The inpt of the *etector is *esigne* to match the signal that is to e analy2e* on


26/62


Fig+re 9

Coa>ia* Atten+ator $modW%23')

The coa,ial attenator is a passive component inserte* into a metal container Figure 6F The inpt an* the

otpt se the 5MA coa,ial connector an* are matche* on -


27/62


3t is short-circit termination for wave-gi*e 3t ses the completely close* stan*ar* flange that cases the

complete reflection of the whole inci*ent 4$ signal 5ee Figure !.

Fig+re &

aria,*e Atten+ator $modW%:')

3t consists of a V!: straight sectionV where a plate is monte* in the central part an* the intensity of the

electrical fiel* is ma,imm The *epth of insertion of the plate is a*.stale an* the intro*ce* attenation

varies conse0ently 5eeFigure " The attenation level can e a*.ste* from


28/62


LAB S#SSIO( &

OB#CT)

Determination of 3nsertion loss in a wavegi*e commnication system

#65IP#(T)

1 Transmitter Mo*le M!-T1 Up %onverter nit mo*le M!-U%

1 5!4HLEEL meter nit mo*le M!-MT) !avegi*e mo*les M!-'

) !:H%oa, A*apter Mo*le M!-1

1 $i,e* attenator mo*le M!-(

1 $i,e* attenator mo*le M!-?1 )* %o-a,ial attenator mo*le M!-)'

1 slotte* line mo*le M!-


29/62


The attenation or insertion loss A of a component of the transmission system is calclate* with the following

formla

!here/

+in K inpt power

+ot K otpt power

!here/+*#m K signal power e,presse* in *#m

+ K signal power e,presse* in m!

PR#%LAB TASKS)

61 Define 3nsertion Loss in a !avegi*e

62 what are the cases of 3nsertion LossQ An* how it can e avoi*e*Q

PROC#.5R#)

1 %arry ot the wiring etween the nits as shown in $igre 1

2 set the transmitter nit in the following operating mo*e 5!1 K 15!) K 15!' K Direct

Level K -)

2 %alclator the gain 4 of the antenna at the fre0ency of 1? :=2/ sing the formla A vale isotaine* near the nominal one

!here Jg K wave-length in gi*e

Jo K wave-length in free space A K srface a , ,' of the horn antenna opening

3 %arry ot the same calclation for the horn antenna M!-1


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11 Ta"e care *ring the e,ercise *o not change the meter caliration again of the level of the emitte*power

12 The formla of the power of the receive* signal + 4 can e simplifie* with

13 %onsi*ering the open gi*e as an isotropic antenna :wK1F/ the last relation ecomes

18 Bn the open wave gi*e mont a horn antenna mo* M!-1

1; Move the receiving station away ntil the meter gives the same rea*ing seen efore 1F that will eotaine* at new *istance D) in this sitation the same power +4 of the last cases is receive* t at a

*ifferent *istance/ the formla ecomes

1& The gain of antenna M!-1< is calclate* y *ivi*ing memer y memer the e0ation )F y thee0ation 1F

1

The otaine* reslt shifts of some *# from the nominal gain/ as the open gi*e is not an i*eal isotropic

antennaX

20 The gain of antenna M!-1> is calclate* y *ivi*ing memer y the memer the e0ation 'F y thee0ation 1F

21

- '; -


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OBS#RATIO(S CALC5LATIO(S)

R#S5LT)

- '< -


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LAB S#SSIO( 10

OB#CT)

Measrement of the gain of 7OR( Antenna C sing Metho* of the two antennas

#65IP#(T)

1 Transmitter nit mo*M!-T1 Up-%onverter nit mo* M!-U%

1 5!4HLEEL meter nit mo* M!-MT

) !:H %oa, a*apters mo*M!-1

1 1

1 ariale attenator mo*M!->1 $i,e* attenator mo* M!(

) !ave-gi*es mo* M!-'1 Trn tale with sli*e mo* M!-))

1 Detector mo* M!-;

) =igh spports mo*

) 5MA-5MA coa,ial cales1 #N%- #N% coa,ial cale

1 %ale with ) mm-plgs1 Mltimeter

T7#OR/)

Use two i*entical antennas as shown in figre 3f 4> is the gain of each/ from the formla of the receive*power P4$4335 e0ationF we get

PROC#.5R#)1 5et the Meter nit in the following operating mo*e

5!1K 1m5!)K BN

2 Two horn antennas mo*M!-1> are se*

3 %arry ot the wiring as in*icate* inFigure 1etween the nits

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8 5et a *istance D of 1cm etween the antennas opening

9 +ower the two nits sing the start p switch set on the rear si*e

: Align the transmitting an* the receiving stations to get the ma,imm rea*ing on the meter

; %alirate the meter so to otain/ eg/ the in*ication ) an* aot ))m with the mltimeter

& The gain :M!1> of antenna is calclate* sing 1F

The ratio +4 H +T can e evalate* as follows remove the two antennas mo*M! -1> an*connect the two sections etween them via the variale attenator mo* M!-1> as in figre

A*.st the attenator p to otain the same rea*ing seen efore )F on the meter an* aot))m with the mltimeter that correspon*s to -)>m thatcorrespon*s to -)*#mF %onsi*ering the fi,e* attenator/ the receive* level is ;*#m K -)*#m

Y >*#F The ratio correspon*s to the inserte* attenation/ so e0al to )@*# K;*#m - -) ecomes

11 %alclate the gain of the antenna n*er measrement

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R#S5LT)

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LAB S#SSIO( 11

OB#CT)

#y the se of the slotte* line/6 To *etermine the n"nown fre0ency6 To *etermine the oltage 5tan*ing !ave 4atio 5!4F an* 4eflection %oefficient

#65IP#(T)

Transmitter Mo* M!-T/

Bne slotte* line M!-


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%hec" if the *istance etween minimm an* ma,imm is e0al to [ the wavelength/ in other wor*s yvarying the fre0ency an* repeating measrement/ yo can oserve how the *istance etween ma, an* min is

longer or shorter if yo *ecrease or increase the fre0encyG repeat the e,ercise with termination of 1 ohmNote that/ with the help of slotte* line/ yo can *istingish if the loa* is greater or smaller than the

characteristic impe*ance of the line/ 3n fact/ with 1 ohm the voltage minimm is at [ wave length from the

loa*/ while on the loa* there is a ma,immG with


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PROC#.5R#)

1 %onnect the generator transmitterF to the slotte* line throgh 4$ cale

2 Terminate the line y attaching a loa* RLF on other en* of line

3 3nsert proes of voltmeter in the slots provi*e* on the trailer of the slotte* line

8 Trn on the generator an* e,cite the cale with 4$ waves9 Move the trailer on the slotte* line +ositions of ma,imm & minimm voltage

Appear alternately on the slotte* line

: Note *own the ma, & min vales of voltage

; Also note *own the positions of the voltage minima an* voltage ma,ima on the scale

& Determine 5!4 y the following formla

Determine the calclate* 5!4 y the formla

10 %alclate the n"nown fre0ency with the help of the following formla

11 4epeat same proce*re for *ifferent loa*s RLF

OBS#RATIO(S)

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CALC5LATIO(S)

R#S5LT)

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LAB S#SSIO( 12

OB#CT)

#y se of slotte* wavegi*e6 To oserve how the loa* impe*ance affects the 5!4

6 To *etermine when a wavegi*e is properly terminate*

#65IP#(T)

1 Transmitter Mo*le M!-T1 Up %onverter nit mo*le M!-U%

1 5!4HLEEL meter nit mo*le M!-MT1 !avegi*e mo*le M!-'

) !:H%oa, A*apter Mo*le M!-1

1 $i,e* attenator mo*le M!-(1 )* %o-a,ial attenator mo*le M!-)'1 slotte* line mo*le M!-


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PR#%LAB TASKS)

61 5tate a*vantages of wavegi*es over transmission line

62Discss *ifferent mo*es that propagate throgh a !avegi*e

PROC#.5R#)1 %arry ot wiring etween the nits as in*icate* inFigure 2 note that the final transition with the

coa,ial attenator mo*le M!-)' represent the n"nown loa* that is to e measre*F

2 Ta"e care to the connection etween the transmitter nit an* the inpt of the U+- converter nit si*e inwhich there are the le* an* the power spply inptXF

3 5et the meter nit in the following operating mo*e

8 +ower the two nits the start p switch set on the rear si*e

9 Move the trailer of the slotte* gi*e to the n"nown impe*ance a*apter pls attenatorF

: Note that the vales e,presse* *ring the e,ercise col* e *ifferent as the impe*ance is not i*eal; Move the trailer an* note the position of the first minimm $. m1K . LF

& Move the trailer an* note the position of the first ma,imm .M1F an* calirate the instrment to thema,imm in*ication

Move the trailer an* note the position of the secon* minimm .m) an* measre the 5!4 on the

instrment

10 3f JgJ2 is e0al to the *istance etween the two minimm vales/ calclate Jg that will e e0al to

aot ; cm11 %hange the a*apter an* coa,ial attenator with the short circit12 Move the trailer an* fin* the new first minimm vale/ ne,t to the last .sF

13 %hec" again the measrement of JgJ)18 4epeat for *ifferent types of loa* RLF

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R#S5LT)

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LAB S#SSIO( 13

OB#CT)

To measre n"nown loa* impe*ance attache* to a wavegi*e sing the smith chart

#65IP#(T)

1 Transmitter nit mo*le M!-T

1 Up converter nit mo*le M!-U%

1 5!4HLEEL meter nit mo*le M!-MT1 wave gi*e mo*le M!-'

) !:H%oa, A*apter mo*les M!-1

1 $i,e* attenator mo*le M!-(1 )*# %o-a,ial attenator mo*le M!-)'1 slotte* line mo*le M!-

tc 382 antenna and microwave

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