back2.m

实现smith圆图显示和阻抗匹配

 for G=[0 0.2 0.5 1 2 ];
    for B=[-4 -2 -1  -0.5 -0.3 0.3 0.5  1 2 4];%循环输入归一化阻抗
tr=2*pi*(0:0.005:1);
rr=1/(1+G);cr=1-rr;
plot(-cr+rr*cos(tr),rr*sin(tr),'g');%画电阻圆
axis square;
hold on;
b=B;
rx=1/b;cx=rx;
tx=2*atan(-b)*(0:0.01:1);
if tx<pi
plot(-1-rx*sin(tx),-cx+rx*cos(tx),'g')%画电抗圆
else
plot(-1-rx*sin(tx),cx+rx*cos(tx),'g')
end
hold on;
  end
end
t=-1:0.001:1;%画横轴
plot(t,0,'g');
axis square;
hold on;