I am not certain what the correct argument would be here for your rfplot call (using ‘s_params’ is noi correct). I corrected as much as I could.
% Initialize RF toolbox
clc;
clear;
% Define frequency range (1 GHz to 10 GHz)
f = linspace(1e9, 10e9, 201); % Frequency points
% Create Transmission Line objects using 'rfckt.cascade'
% Specify characteristic impedance and electrical length for each transmission line
% Transmission Line 1
z0_1 = 50; % Characteristic impedance (Ohms)
el_1 = 90; % Electrical length (degrees)
tl1 = rfckt.txline('Z0', z0_1, 'StubMode', 'NotAStub', 'Termination', 'NotApplicable');
set(tl1, 'LineLength', el_1, 'Freq', f);
analyze(tl1, f)
% Transmission Line 2
z0_2 = 75; % Characteristic impedance (Ohms)
el_2 = 45; % Electrical length (degrees)
tl2 = rfckt.txline('Z0', z0_2, 'StubMode', 'NotAStub', 'Termination', 'NotApplicable');
set(tl2, 'LineLength', el_2, 'Freq', f);
analyze(tl2, f)
% Transmission Line 3
z0_3 = 100; % Characteristic impedance (Ohms)
el_3 = 30; % Electrical length (degrees)
tl3 = rfckt.txline('Z0', z0_3, 'StubMode', 'NotAStub', 'Termination', 'NotApplicable');
set(tl3, 'LineLength', el_3, 'Freq', f);
analyze(tl3, f)
% Cascade the transmission lines
cascaded_tl = rfckt.cascade('Ckts', {tl1, tl2, tl3});
% Analyze the cascading transmission line across the defined frequency range
analyze(cascaded_tl, f);
% Plot S-parameters of the cascaded transmission line
figure;
s_params = cascaded_tl.AnalyzedResult.S_Parameters;
rfplot(s_params, 'db', f);
title('S-Parameters of Cascaded Transmission Lines');
xlabel('Frequency (Hz)');
ylabel('Magnitude (dB)');
% Analyze Impedance, VSWR, and more
z_params = cascaded_tl.AnalyzedResult.Z_Parameters;
vswr = cascaded_tl.AnalyzedResult.VSWR;
figure;
plot(f, vswr);
title('VSWR of Cascaded Transmission Lines');
xlabel('Frequency (Hz)');
ylabel('VSWR');
grid on;
% Displaying results
disp('Impedance of the cascaded transmission lines:');
disp(z_params);
disp('S-parameters of the cascaded transmission lines:');
disp(s_params);
.
