武漢大學(xué)射頻電路第九次作業(yè)

1、精選優(yōu)質(zhì)文檔-傾情為你奉上第九次作業(yè) 電子與通信工程 王世杰 881. 已知晶體管在2.0+0.188GHz處的S參量為S110.6525, S120.119, S215.0110, S220.65-36。用輸入不匹配輸出匹配方案設(shè)計放大器，在圓圖上分別畫出增益為最大可能增益的90，80%，50的等資用功率增益圓。若源阻抗及負(fù)載阻抗均為50歐，對于增益是50的情況設(shè)計具體的匹配網(wǎng)絡(luò)。解：計算K和D值為：K=1.0007，D=0.9725,由此可以看出該晶體管絕對穩(wěn)定。計算可得該放大器的最大增益=43.8，化為分貝表示為：= 16.4147 dB,畫出資用功率分別為15.9572 dB，15.4

2、456 dB，13.4044 dB的等資用功率圓如圖所示：取 ，則：，得到 L=out*=0.88+0.4 i。根據(jù)和設(shè)計匹配電路：輸入端：并聯(lián)4.1nH的電感，然后串聯(lián)11.8nH的電感輸出端：并聯(lián)523.5pF的電容，然后串聯(lián)30.7nH的電感function k,delta,u = K_factor(s_param) % Usage: k,delta = K_factor(s_param)% Purpose: returns k factor for a given s-parameter matrix% if k1 and delta1 then circuit is uncoditi

3、onally stable% otherwise circuit might be unstable s11=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+delta2)/(2*abs(s12.*s21);u=(1-abs(s11)2)/(abs(s22-s11*conj(D)+abs(s12)*abs(s21);Endfunction Gamma_S,Gamma_out = ZiYongGain(s_pa

4、ram,G_goal)%UNTITLED11 Summary of this function goes here% Detailed explanation goes here hold on;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);% find constant operating power gain circlesdelta=det(s_param);K=(1-abs(s11)2-abs(s22)2+abs(delta)2)./(2*ab

5、s(s12.*s21);ga=G_goal/abs(s21)2; % normalized the operating power gain% find the center of the constant operating power gain circledga=ga*conj(s11-delta*conj(s22)/(1+ga*(abs(s11)2-abs(delta)2); % find the radius of the circle rga1=sqrt(1-2*K*ga*abs(s12*s21)+ga2*abs(s12*s21)2);rga=rga1/abs(1+ga*(abs(

6、s11)2-abs(delta)2); % plot a circle in the Smith Charta=(0:360)/180*pi;hold on;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=%g dB,G_goal_dB);plot(real(dga)+rga*cos(105),imag(dga)+rga*sin(105),bo);text(real(dga)+rga*cos(105)-0

7、.05,imag(dga)+rga*sin(105)-0.07,bfGamma_S);Gamma_S=(real(dga)+rga*cos(105)+1j*(imag(dga)+rga*sin(105);Gamma_out=s22+s12*s21*Gamma_S/(1-s11*Gamma_S);endclose all;clear all;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,u = K_factor(s_param) % check stabilityG_Tmax=abs(s21)*(K-sqrt(K2-1)/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_T