How to model Klopfenstein Taper in CST MWS?

Hi,

I am simulating some antennas on CST MWS.
Does anyone know how to model a Klopfenstein Taper ? Is there any existing program on how to calculate or generate the coordinates ?

Thanks in advance

Regards,
abti

klopfenstein transformer

Hi abti,
you must draw it in AutoCAD and save as *.dxf and load in CST.
for drawing in AutoCAD you can use AutoLISP to draw any function y=f(x). I attached a AutoLISP routine for this porpose.Please folow me:
1. find my AutoLISp file.
3. edit it by filling "x" and "y" with correct value that you want to draw.
2. open AutoCAD and Operate : Tools\AutoLISP\Load menu and load this routine.
3. After Successfully loading, type "balun" in command line of AutoCAD.
4. your y = f(x) curve is plotted. save it and load in CST or HFSS or others simulators.

KMPA

klopfenstein taper design

I've question relating to length of Klopfenstein taper.

I designing impedance transformer at 1-5 GHz band. How depends length of transformer on the bandwidth?

For example by using Tchebyshev λ/4 transformer, I can simply calculate number of section for securing needed bandwith.

Thanks fo help and apologize me for my English

Re: Klopfenstein Taper

i am having matlab code for this tapper....

Re: Klopfenstein Taper

Dear theepak

Could you send me your code. Thank you

Re: Klopfenstein Taper

Hallo theepak,
the minimum operating frequency decreases with increasing length.
fmin and waveguide loss are the tradeoffs.
elektr0

Re: Klopfenstein Taper

This code i got from matlab website....


function Zlist=bklop(Zo,Zload,N,RdB)
% Calculate impedance list for a Klopfenstein taper
% of unit length.
%
% Zlist=bklop(Zo,Zload,N,RdB)
%
% Zo......Characteristic impedance (Ohms)
% Zload...Load impedance to match to (Ohms)
% N.......Number of sections used to approximate taper (integer)
% RdB.....Operating band ripple (dB)
%
% e.g. Zlist=bklop(50,100,60,-25) % Match a 100ohm load to a 50ohm line
% % with operating band ripple at -25dB.
% % Taper defined as list of 60 sections
%
% Note : Only valid for Zload>Zo
%
% Matches a load impedance Zload to a standard line impedance Zo
% using Klopfenstein taper.
% Taper profile is returned as a list of impedances, the optimum length
% for this design of taper is 0.565 lambda.
%
% Impedance Values
% Zo ---> [ Z1 ] [ Z2 ] .... [ ZN ] <-- Zload
%
% Ref D.M Pozar Microwave Engineering 2nd Ed Page 291

% N.Tucker **broken link removed** 2010




Tld=log(Zload/Zo)*0.5; % Reflection coefficient of load
Trip=10.^(RdB/20); % Lin value of ripple in operating band


A=acosh(Tld/Trip); % Intermediate variable in calculation


z=0; % Fractional distance along taper
dz=1/(N-1); % Incremental distance


Zx=zeros(1,N);
for c=1:N % Loop for impedance values along taper

M=round(z*100+25); % Number of steps for the numerical integration
PsiXA=0;
y=0;
dy=((2*z-1)/(M-2)); % Increment for numerical integration

for d=1:M % Loop for PsiXA numerical integration
PsiXA=PsiXA+besseli(1,A*sqrt(1-y.^2))/(A*sqrt(1-y.^2))*dy;
y=y+dy;
end

% Calculate impedance as a function of distance along the
% unit length transformer
LNZx=0.5*log(Zo*Zload)+(Tld/cosh(A))*(A.^2)*real(PsiXA);
Zx(1,c)=exp(LNZx);
z=z+dz;
end


Zlist=[Zo,Zx,Zload]; % Assemble the list of impedances for output
X=1:1:N; % X-axis vector for plotting

figure(10);
plot(X,(Zx),'b-',X,(Zx),'+');
xlabel('Zo Matching Section Number Zload');
ylabel('Impedance (Ohms)');
title('Transformer Impedances')
grid on;

chartname=sprintf(' Transformer Impedances ');
set(10,'name',chartname);