excomp1.m

% Plot Exponential, Triangular and Klopfenstein taper responses
%
% Using very short (lambda/100) transformers,
% a tapered match can be approximated.
% 
% The total length is given by : (Number of sections)*(Transformer Length)
% In this example N*Tlen=0.50 wavelength at Fo.
%
% Load=100 Ohm
% Line=50 Ohm
% Number of sections N=50
% Operating band ripple -35dB (Klopfenstein only)
%
% Transformer lengths Tlen=lambda/100
% Fo=1000 Mhz
% Plot 1 to 10000 MHz
%


clc;
close all;
help excomp1

Zload=100;  % Load impedance, to matched (Ohms)
Zo=50;      % Characteristic impedance to match to (Ohms)
Fo=1000;    % Lower cut-off frequency (MHz)
F1=1;       % Start frequency for response plot (MHz)
F2=10000;   % Stop frequency for response plot (MHz)
Tlen=0.01;  % Transformer length as a fraction of wavelength
N=50;       % Number of transformer sections
RdB=-35;    % Operating band ripple (dB)

             
Zlist1=bexp(Zo,Zload,N);        % Exponential taper impedance list
Zlist2=btri(Zo,Zload,N);        % Triangular taper impedance list
Zlist3=bklop(Zo,Zload,N,RdB);   % Klopfenstein taper impedance list

% Return loss and smith chart plots
bplot(Zlist1,Tlen,Fo,F1,F2);
bdraw(Zlist2,Tlen,Fo,F1,F2,'g-');
bdraw(Zlist3,Tlen,Fo,F1,F2,'b-');
axis([0 F2 -50 0]);

% Legend for return loss plot
figure(5);hold on;
x=[0,0];y=[0,0];
H=plot(x,y,'r-',x,y,'g-',x,y,'b');
legend(H,'Exponential','Triangular','Klopfenstein');

% Impedance profile plot
figure(10);
clf;
X=1:N;
H=plot(X,Zlist1(2:N+1),'r-+',X,Zlist2(2:N+1),'g-+',X,Zlist3(2:N+1),'b-+');
legend(H,'Exponential','Triangular','Klopfenstein',4);
xlabel('Zo     Matching Section Number    Zload');
ylabel('Impedance (Ohms)');
title('Transformer Impedances')
grid on;