tl_bpf_nov05_4.m

计算周期传输线结构带通滤波器特性参数的程序

%归一化后再计算
% Network: L/2 -- L(<2nH) -- L/2   0Hz no passband,passband:f0,2f0,3f0...
hold off

% parameters define
z0 = 50;
f0 = 3000;
bw = 0.1;
l = 3E8/(2*f0);
%c0 = 4/(z0*pi*2*pi*f0*bw);
l0 = bw*z0/(8*f0);
% main loop
for f = 5000:5:10000;
kl = 2*pi*f*l/3E8;
%wc0 = 2*pi*f*c0;
wl0 = 2*pi*f*l0;

A1 = [cos(kl)+0.5*z0*sin(kl)/wl0 -j*sin(kl)-j*0.5*z0*(1-cos(kl))/wl0;
    -j*sin(kl)+j*0.5*z0*(1+cos(kl))/wl0 cos(kl)+0.5*z0*sin(kl)/wl0];
A = A1^2;
%v7a = (A(1,1)*A(2,2)-A(1,2)*A(2,1))/(A(2,2)-A(1,2));    %v7/v1
%i7a = (A(1,2)*A(2,1)-A(1,1)*A(2,2))/(A(2,1)-A(1,1));
S21 = 2/(A(1,1)+A(1,2)+A(2,1)+A(2,2));  %s21
dbs21 = 20*log10(abs(S21));
f
%plot(f,20*log10(abs(v7a)),'b')  %blue line
%plot(f,20*log10(abs(i7a)),'g')  %green line
plot(f,dbs21,'r')  %red line
hold on
end

'=== basic parameters ==='
z0
f0
bw
l
%c0