武汉大学射频电路第八次作业

电子与通信工程王世杰2014282120188第八次作业1、一晶体管的S参量如下：f=750MHz：s11=0.114-j*0.551，s12=0.044+j*0.029，s21=-4.608+j*7.312，s22=0.490-j*0.449;f=1000M：s11=-0.058-j*0.452，s12=0.054+j*0.022，s21=-2.642+j*6.641，s22=0.379-j*0.424;画出晶体管在两个频率下的输出及输入稳定圆并计算各自μ，K,D值。解：当f=750MHz，编程画出输出及输入稳定圆，并计算μ，K,D的值。程序如下：closeall;%closeallopenedgraphsclearall;%clearallvariabless11=0.114-1j*0.551;s12=0.044+1j*0.029;s21=-4.608+1j*7.312;s22=0.490-1j*0.449;s_param=[s11,s12;s21,s22];%converttheS-parametersintomatrixnotationsmith_chart;%createaSmithChartinput_stability(s_param,'r');%plotinputstabilitycircleinredcolorsmith_chart;%createaSmithChartoutput_stability(s_param,'b');%plotoutputstabilitycircleinbluecolor[d,k,u]=K_factor(s_param);输入输出稳定圆如下：|D|=|S11S22-S12S21|=0.5561；2221122122110.60482SSDKSS211*2211122110.7755SSSDSS可知在该频率下晶体管不是绝对稳定的当f=1000MHz时，输入输出稳定圆如下图：|D|=|S11S22-S12S21|=0.4535；2221122122110.80932SSDKSS211*2211122110.9622SSSDSS可知在该1000MHz频率下晶体管不是绝对稳定的2、已知晶体管的S参量在传输线特性阻抗为50Ω测得为S11＝0.57∠170，S12＝0.066∠69，S21＝2.97∠71，S22＝0.46∠-26。其输入端与VS＝3∠0，ZS＝50Ω的电压源连接，输出端口接Zin＝40Ω的天线。求放大器的入射功率Pinc，电源的资用功率PA，负载的吸收功率PL，转换功率增益GT，资用功率增益GA及功率增益G。解：编程计算放大器的入射功率，电源的资用功率，负载的吸收功率，转换功率增益，资用功率增益及功率增益：closeall;%closeallopenedgraphsclearall;%clearallvariablesZ0=50;s11=0.57*exp(j*(170)/180*pi);s12=0.066*exp(j*(69)/180*pi);s21=2.97*exp(j*(71)/180*pi);s22=0.46*exp(j*(-26)/180*pi);Vs=3;Zs=50;Zl=40;GamaS=(Zs-Z0)/(Zs+Z0);GamaL=(Zl-Z0)/(Zl+Z0);D=s11*s22-s12*s21;GamaIn=s11-GamaL*D/(1-s22*GamaL);GamaOut=s22-GamaS*D/(1-s11*GamaS);Pinc=1/2*(Z0/(Zs+Z0)*abs(Vs))^2/abs(1-GamaIn*GamaS)^2Pa=1/2*(Z0/(Zs+Z0)*abs(Vs))^2/(1-abs(GamaS*GamaS)^2)Gt=(1-abs(GamaL)^2)*abs(s21)^2*(1-abs(GamaS)^2)/(abs(1-GamaL*GamaOut)^2*abs(1-s11*GamaS)^2)Ga=abs(s21)^2*(1-abs(GamaS)^2)/((1-abs(GamaOut)^2)*abs(1-s11*GamaS)^2)G=(1-abs(GamaL)^2)*abs(s21)^2/((1-abs(GamaIn)^2)*abs(1-s22*GamaL)^2)Pl=Pa*Gt计算结果如下：2211.12521SincinSbP2211.12521SASbP*8.9549LATPPG222S21L211SoutL117.959911TSGS22S212211Sout111.188411ASGS2221L22in22L111.933411SGS3.已知晶体管在2.0+0.xxxGHz处的S参量为S11＝0.65∠－25,S12＝0.11∠9,S21＝5.0∠110,S22＝0.65∠-36。用输入不匹配输出匹配方案设计放大器，在圆图上分别画出增益为最大可能增益的90％，80%，50％的等资用功率增益圆。若源阻抗及负载阻抗均为50欧，对于增益是50％的情况设计具体的匹配网络。解：计算K和D值为：K=1.0007，D=0.9725,由此可以看出该晶体管绝对稳定。计算可得该放大器的最大增益maxTG=43.8，化为分贝表示为：maxTG=16.4147dB,画出资用功率分别为15.9572dB(90%)，15.4456dB(80%)，13.4044dB(50%)的等资用功率圆如图所示：取0.5570.745sj，则：122122110.838-j0.4851SoutSSSSS，得到ГL=Гout*=0.838+j0.485。根据s和L设计匹配电路,频率为2.137GHz：输入端：并联2.3nH的电感，然后串联8.0H的电感输出端：并联586.4pF的电容，然后串联29.3nH的电感function[k,delta]=K_factor(s_param)%Usage:[k,delta]=K_factor(s_param)%%Purpose:returnskfactorforagivens-parametermatrix%ifk1anddelta1thencircuitisuncoditionallystable%otherwisecircuitmightbeunstables11=s_param(1,1);s12=s_param(1,2);s21=s_param(2,1);s22=s_param(2,2);D=det(s_param);delta=abs(D);k=(1-abs(s11)^2-abs(s22)^2+delta^2)/(2*abs(s12.*s21));endfunction[]=ZiYongGain(s_param,G_goal)%UNTITLED11Summaryofthisfunctiongoeshere%Detailedexplanationgoeshereholdon;s11=s_param(1,1);s12=s_param(1,2);s21=s_param(2,1);s22=s_param(2,2);G_goal_dB=10*log10(G_goal);%findconstantoperatingpowergaincirclesdelta=det(s_param);K=(1-abs(s11)^2-abs(s22)^2+abs(delta)^2)./(2*abs(s12.*s21));ga=G_goal/abs(s21)^2;%normalizedtheoperatingpowergain%findthecenteroftheconstantoperatingpowergaincircledga=ga*conj(s11-delta*conj(s22))/(1+ga*(abs(s11)^2-abs(delta)^2));%findtheradiusofthecirclerga1=sqrt(1-2*K*ga*abs(s12*s21)+ga^2*abs(s12*s21)^2);rga=rga1/abs(1+ga*(abs(s11)^2-abs(delta)^2));%plotacircleintheSmithCharta=(0:360)/180*pi;holdon;plot(real(dga)+rga*cos(a),imag(dga)+rga*sin(a),'r','linewidth',2);text(real(dga)-0.1,imag(dga)+rga+0.05,strcat('\bf',sprintf('G=%gdB',G_goal_dB)));endcloseall;clearall;smith_chart;s11=0.65*exp(1j*(-25)*pi/180);s12=0.11*exp(1j*9*pi/180);s21=5*exp(1j*110*pi/180);s22=0.65*exp(1j*(-36)*pi/180);s_param=[s11,s12;s21,s22];[K,delta]=K_factor(s_param)%checkstabilityG_Tmax=abs(s21)*(K-sqrt(K^2-1))/abs(s12)G_Tmax_dB=10*log10(G_Tmax)G1=G_Tmax*0.9G1_dB=10*log10(G1)G2=G_Tmax*0.8G2_dB=10*log10(G2)G3=G_Tmax*0.5G3_dB=10*log10(G3)ZiYongGain(s_param,G1);ZiYongGain(s_param,G2);ZiYongGain(s_param,G3)Gamma_s=0.93*exp(j*(-126.7943)*pi/180);plot(real(Gamma_s),imag(Gamma_s),'bo');text(real(Gamma_s)-0.05,imag(Gamma_s)-0.07,'\bf\Gamma_S');