Design of a Low Noise Amplifier of RF Communication Receiver for Mine

7/31/2019 Design of a Low Noise Amplifier of RF Communication Receiver for Mine

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0 y pos o l c r c l& l c ro cs r ( M

L N A R v

Yu-na Su, Geng LCollege of Computer Science and Technology, Henan Polytechnic University, JiaoZuo, 454000, ChinaE-mail: [email protected]

Abstract-The de ign w y nd ep of Low Noi e mpli eu ed in ommuni ion e eive fo pe onnel o ien ion

y em in mine i een in odu ed in hi p pe . The key poine n ly i devi e' ili y wi h S ili y oe ien of

de e min ion of he DS of w e nd he inpu nd ou puimped n e m hing wi h Smi h Ch nd Tuning. Fin lly,

he pe fo m n e p me e of LN we e o ined wi h heimul ion of S p me e . The n l imul ion e ul howh he U e of DS fo low noi e mpli e de ign i u eful nd

h good efe en e v lue fo p i l mpli e de ign.d w A ; AD f w ;

; z d

1 NT DUCT N

In the process of coal mine production safety especiallya er the accident, accurate judgment of the miners' location has important signi cance to the personal safety of theminers. In this paper, we design a radio- equency ampli erfor use personnel location system under mines. Theampli er lies in the ont end of the receiver system toampli weak radio-frequency signal that received by itsantennas. In order to suppress noise interference andimprove the sensitivity of the system, we design a low noiseampli er (LNA).

The ADS so ware is a microwave circuit andcommunication system simulation so ware developed byAgilent. It has very power l ability in circuit design andsimulation analysis. Through the S parameter simulation, wecan get information on the gain, stability gure and noise

gure of the circuits easily.

II. ES GN CESSThe main technical indexes of the LNA: working

equency om 2.4 Hz to 2.5 Hz, noise gure(NF) less than 0.8dB, gain more than 15dB.

Component choice is vital to design the LNA. According to the designing demand we choose low noise P MTATF54143 manufactured by Avago.

A Designf bias circuit According to the datasheet of ATF54143, we know that

the noise gure(FJ is close to the minimum noise gure of ATF54143 and the gain is about 16.3dB whenf = 2GH z , Vds= 3V , / s = 20m A . I t can satisf desig n demand ,so we choose this point as the quiescent point of ATF54143.Bias circuit is shown in FigureI

B Stabili f L ABecause of the exist of re ected wave, ampli er will

8- - - - / /$ EEE

[39pLl n

Figure 1 DC Bias circuit diagram

generate self-oscillation in some equencies or endconditions and cannot ampli signal. So stability is a veryimportant factor we must take into consideration in thedesign of ampli er. We have to judge the ampli er isstable absolutely or not before designing matching circuit.Stability depend on S parameter of the transistor, matching network and biasing requirements. The su cient and necessary conditions of absolute stabili are

l- IS 12 - IS 2 2 1

2 _1 1

2 K > 1 1S 2 IIS21

I I = IS llS 2 2 - S 2 S 2 1 < 1 2ATF54143 isn t stable absolutely in some equencies.

We add negative feedback circuit in the source electrode inorder to improve stability. The circuit is shown in FigureIIn the circuit, we add short microstrip lines of appropriatelength between the source and ground. It acts as addingfeedback inductance in the source.

It is very complex that directly calculating stability gureby the datasheet, so we can use stability coef cient of theADS so ware to analysis the stabili of the ampli er. The

simulation result is shown in Figure 2. From the gure wecan known that two coe cients are greater thanI, so the transistor is stable absolutely in working equencies.

86

86

freq

freqS ab ac

6 7 8 9

e Figure stability figure


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C Design of matching network of input terminalThe design uses distributed parameter elements on

account of high working equency. We ve got to balance

gain and noise gure in designing because the inputimpedance when LNA has maximum gain is di erent that when LNA has minimal noise. The noise gure of receivingsystem is mainly determined by the rst LNA , so thedesign use minimal noise matching principle. In order to get

a o se gu e e ect o coe c e t o put te amust satis requirement of best source re ection coef cient( ra pt ). If termination impedance and characteristicimpedance of microstrip line are 50 ohm, matching networkof input terminal has to convertr P t into 50 ohm. Thisdesign uses type L matching network. First, we designmatching network of input terminal withDA_SmithChartMatch of ADS so ware roughly, determineit's parameters approximately, then optimize with Tuning tool of ADS so ware. The matching network of input terminal is shown in Figure 3.

UN

Z = 5 0 Ohm Z = 5 0 Nu =2

1 88 it}F=? 7 GHz

Figure 3 matching network of input terminal

D. Design of matching network of output terminalMatching network of output terminal is for increasing

gain, improving gain atness and input VSWR, so thedesign use maximum gain matching principle. First, we alsodesign matching network of output terminal withDA_SmithChartMatch of ADS so ware roughly. Thesimulation results show that return loss of output terminal isgood, but return loss of output terminal is bad. So, we have to optimize the whole circuit with Tuning tool of ADSso ware, nd a balance in some performance parameters of the LNA such as S11,S22,S21, noise gure. The matching network of output terminal is shown in Figure 4.

TUN UT

Ohm' u =2E=35.07 IF 45

Figure 4 matching network of output terminal

E. Determining the size of microstrip lineWe choose 4 substrate. It's relative dielectric constant

Er = 4.4 ,thicknessh = 0.8 , permeability Mur= 1 ,metalconductivity Cond= 5.88 7 ,conductor thicknessT = 0.035 . We can easily compute width and length of matching microstrip line with microstrip line computational tool LinCale of ADS so ware. The schematic is shown inFigure 5.

6

Figure 5 schematic of the LNA

III. MULAT N ESULTThe simulation results are shown in Figure 6, Figure 7.

Form Figure 6, we can see that in operating equency rangeinput re ection coef cient S 1,1 and output re ectioncoef cient S 2,2 are less than -15dB, interband gain ismore than 15dB, gain atness is good. Form Figure 7, wecan see that in operating equency range noise gure is less than 0.8dB, stability gure is more than 1, the whole circuitis unconditionall stable.

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0$ 1 I 20 H 3 3!frcq C

a z

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Figure 6 simulation results of S parameters

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Figure7 simulation results of stability and noise gure

IV. C NCLUS NThis paper discusses the design process of LNA with

ADS so ware. First, we choose suitable device according to the designing demand, design DC bias circuit. Then, wedesign matching network with DA _SmithChartMatch andTuning tool of ADS so ware. We use maximum gainmatching principle on output terminal and minimal noisematching principle on input terminal during designing of matching network. Using DA SmithChartMatch andTuning tool of ADS so ware can save a large number of calculations and analyses, simpli the process of design,shorten the design cycle, reduce production cost.


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EFERENC S

[I) Xu Xingfu. "Rf circuit design and simulation examples of ADS200(2009 Publishing House of Electronics ndustry.

[2) Reinhold Ludwig , Pavel Bretchko."R Circuit Design: Theory andApplications (2002 Publishing House of Electronics ndustry.[3) Wan Jiangang, Gao Yuliang, Zuo Zhifang. Simulation and Design of

a Broadband Low Noise Amplifier Based on Simulation SoftwareADS . Telecommunication Engineering, 2009,49(4 ,pp.5 -61.

[4) Tang Haixiao, Zhang Yuxing, Yang Chenqing, Yang Yumei. "An XBand Low Noise Amplifier Design with ADS So ware .Telecommunication Engineering, 2006,01 ,pp.119-122.

[5) Huang Yulan. "Rf circuit design basis and typical application .(201O People's Post and Telecommunication Publishing House.

[6) Gong Bo, Li Shuhua. "Design and simulation to improve the lownoise ampli er of communication equipment based on ADSso ware . Electronic Design ngineering,2010,I (2 ,pp.121-124.

[7) Dong Liyuan, Wu Chunjie, Liu Jingbing. "Design and fabrication of low noise amplifier at 2.25GHz using ADS .Cryogenics,20 10,38(9 ,pp.22-26.

Design of a Low Noise Amplifier of RF Communication Receiver for Mine

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