ctho-minimum nf lna-group1-07091023.docx

7/29/2019 CTHO-Minimum NF LNA-Group1-07091023.docx

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I HC QU C GIA TP. HCMTRNG I HC BCH KHOA

Microwave circuits project

DESIGNING A LOW NOISE AMPLIFIER

MINIMUM NF at 2.4 GHZ

HVTH: Trn Minh Tr - MSHV: 12810070 Hng Nht- MSHV: 11140039

GVHD: TS. HUNH PH MINH CNG

Cn Th, thng 09 nm 2013


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NI DUNG Abstract Introduction Mch khuch i nhiu thp Thit k mch LNA: Minimum tn s 2.4 GHz dng transistor

AT32033 (tnh ton kt hp vi s dng cc phn mm ADS v

AppCAD)

Kt lun Reference


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Abstract - B{i vit trnh b{y c|c bc thit kmch khuch i nhiu thpvi h s

nhiu nh nhttitn s 2.4 GHz. Mch c thc hin da trnla chn transistor

AT32033 kt hp c|c tnh to|n v{ phn mm ADS, AppCAD m phngv{ x|c nh

c|c thng s ca mch khuch i.

INTRODUCTION

Trong lnh vc siu cao tn, c rt nhiu loi mch khuch i kh|c nhau nh mch

khuch i nhiu thp, mch khuch i cng sut

Trong phn sau ca bi vit, chng ti s thit k mch LNA vi iu kin h s nhiu

cc tiu tn s 2.4 GHz. Vi s h thng nh sau:

MCH KHUCH I NHIU THP - LNA

B khuch i nhiuthp - LNA l v cng cn thit trong h thng thng tin v tuyn,cbit l{ pha thu. V tr LNA t c{ng gn anten thu c{ng tt. V khi , tn hiu v tuyn thuc t anten - tn hiu rt yu(v cng sut)s c khuch i thng qua LNA. ng


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thi, vi thit k c bit, LNA s khuch i cng sut tn hiu vi mc nhiu l{ ti u thpnht. Khi ,h s nhiu NF s l{ thp nht trn c scng thc Friiss.

Cc bc thc hin LNA vi h s nhiu cc tiu

Bc 1: X|c nh tnh n nh ca transistor dng thit k mch LNA vi nhiu thpnht

iu kin transistorn nh khng iu kin (unconditionally stable) l{:

Hay thng qua h s :

Khi hai iu kin trn khng tha m~n tc transistor c chn n nh c iu kin.

Khi ta phi x|c nh c|c vng trn n nh t ch ra vng hot ng n nh catransistor.

Tnh tm v bn knh n nh ng vo v ng ra:

+ T}m v{ b|n knh ng trn n nh ng v{o.


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+ Tm v bn knh ng trn n nh ng ra.

Bc 2 :H s nhiu nh nhtF= Fmin , S= opt

Tnh h s phn x ti L, c c li ln nht c th khi ta c:

Tnh to|n li tng cng ti ng ra ca mch khuch i vi ch s nhiu F min:

Vi

Bc 3phi hp tr kh|ng dng ng d}y truyn sng (cng c th dng c|c phn t Lhay C) :


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Kt hp c|c thng s S v L tnh c trn v{o phi hp tr kh|ng. Th mch sau phi

hp c dng:

Sau tnh ra d{i thc t ca c|c d}y truyn sng trn.

Cch chn transistor:

- Thng s S ca ca mng hai ca:

[

] [

]

[

] [

]

- Chn transistor c cc thng s S ph hp c th nh sau:

S11: h s phn x ng vonn nh hn 1 v cng nh cng tt

S22: h s phn x ng ra nn nh hn 1 v cng gn 1 cng tt

S12: h s truyn nghch nn cng nh cng tt (rt nh c th xem nh bng 0 transistor

c th xem l n hng).

S21: h s truyn thun nn cng lncng tt cc i ha li.


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Cc thng s nh gi cht lng ca mch

+Thng s S11 v{ S21: S21 phi c im nh ti tn s 2.4 GHz, S11 phi c |y ti tn

s 2.4 GHz, nh hnh v sau. Nhiu ng v{o v{ ng ra rt nh xung quanh tn s 2.4

GHz.

2.Thit k mch LNA 2.4GHz (NF=minimum NF)Chn transistor AT32033 vi Vce=5 V, Ic=2mA, Z0= 50 ti tn s 2.4GHz c c|c thng s:

S parameter Noise parameterS11 S21 S12 S22 Rn opt Fmin (dB)

0.14151o 1.7951o 0.17560o 0.62-44o 0.07 0.39-166 1.60

Tnh to|n n nh: = S11.S22 S12.S21

|| = 0.223 < 1 (1)

= 1.033>1 (2)

T (1) v (2 ) ta c:

1 suy ra transistorAT32033 n nh v iu kin

Thng s nhiu ca transistor (do nh sn xut cung cp):Freq-MHz Fmin-dB opt-mag opt-ang rN_normalize2400 1.6 0.39 -166 0.07

Nn nhiu: F = Fmin = 1.6dB ; s=opt= 0.39


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Tnh h s phn x pha ti :

L =0.746675


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Phi hp tr khng ng ra: (*out=L =0.746675


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Kt qu mch sau phi hp tr khng :

d{i thc t ca c|c d}y truyn sng khi s dng board FR4 (Er=4.6; H=6 mm, T=2mm,

f=2.4 Ghz)nh sau:

Tng kt: - Input matching circuit:

o Open stub: 0.1101, w = 10.672 mm, l = 7.279 mm.o Line length: 0.0754 , w = 10.672 mm, l = 4.987 mm.

- Output matching circuit:

Open stub: 0.1833, w = 10.672 mm, l = 12.1146mm. Line length: 0.2439, w = 10.672 mm, l = 16.1183mm

Ref

1 2

S-PARAMETERS

TermTerm

S_Param

TLINTLINTLIN TLIN

S2P

Term2Term1

SP1

TL4

TL3TL2 TL1

SNP1

Z=50 OhmNum=2

Z=50 OhmNum=1

Step=10 MHzStop=2.8 GHz

Start=1.8 GHz

F=2.4 GHz

E=66.003Z=50.0 Ohm

F=2.4 GHzE=87.816

Z=50.0 Ohm

F=2.4 GHzE=39.659

Z=50 Ohm

F=2.4 GHzE=27.172

Z=50.0 Ohm

File="C:\AT-32033.s2p"

AT32033


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Kt qu t c:

- Thng s S11 v S21


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*Nhiu ng vo v ra :

V. Kt lunM phng trn phn mm ADS cho kt qu gn chnh x|c vi tnh to|n l thuyt v{ ~ t

c c|c yu cu thit k. Tuy nhin, trn thc t vn c s sai lch gia kt qu m phngv{ tnh to|n so vi kt qu c o lng thc t do mt s nguyn nh}n nh s thay inhit mi trng, s mt phi hp tr kh|ng v{ c|c t|c ng in t trng ln nhau cacc phn t mch khi sp xp c|c linh kin trn mch. Do , cng vic tip theo l{ cn phio lng c|c thng s theo c|c tiu ch |nh gi| trong nhiu iu kin kh|c nhau trong thct m bo mch hot ng n nh.

Reference

[1] David M. Pozar, Microwave Engineering, John Wiley&Son, 4th ed. 1998.[2] G. Gonzalez, Microwave Transistor Amplifiers Analysis and Design, Prentice Hall, 2nd ed.1997.

[3] Huynh Phu Minh Cuong, Lecture slides: Microwave Intergrated Circuits.

ctho-minimum nf lna-group1-07091023.docx

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