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实现smith圆图显示和阻抗匹配

for R=[0 0.2 0.5 1 2 ];
    for X=[-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+R);cr=1-rr;
plot(cr+rr*cos(tr),rr*sin(tr),'g');%画电阻圆
axis square;
hold on;
x=X;
rx=1/x;cx=rx;
tx=2*atan(x)*(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;