retrieve metamaterials matlab

Hi guys,
I'm trying to repeat a work recorded in "Negative index bulk metamaterial at
terahertz frequencies". I used CST to simulate the structure and get the S parameters which keep quite good accordance on magnitude with the data shown in the paper. I made a simple retrieve code based on robust method proposed by Kong in matlab language. These stuffs could be found in the attachment below. But the retrieved parameters are quite different from those given by the author. Particullaly, the impedance, which should be very easy to be extracted is also wrong. Other repeated work also verify that there are some problems in my retrieving process.By the way, My code works well for the inplane incidance.
1, is my code right(i just wanna to extract the impedance)?
2, is the phase given by cst right?
3,is the robust method could be used in fishnet structrue?
thanks

hi i upload my matlab code in:
https://www.edaboard.com/viewtopic.p...849&highlight=

don't forget HELP

Thanks! I've solved the problem in CST. the point is that I should deembed the parameters first or use open boundary instead of open add space. THanks a lot!

dear smith

would you please send me your matlab code. my code have some problem that i dont know that how i can solve them. then if it is possible for you i want to compare our codes to remove these problems.
regards

the attachment is my code. I saw your request yesterday when i tide my email box, sorry for delay. hope we could dicusss on the retrieval together

Added after 4 minutes:

sorry,here is the attachment

I think you should add part C of this paper for more accuracy
they tell how to determine n and z into 4 condition

|z'|>=delta and z >=0
|z'|>=delta and z < 0
|z'|<=delta and |eink0d|<=1
|z'|<=delta and |eink0d|> 1

but i still not clear in part D (determination of branch of n')
Could any one explain me in this part for easier to understand.

Regards,

dear smithjim
thank you very much, but why you use negative sign for :
s11=s11(2,:).*exp(-i.*s11(3,:)*pi/180);

Added after 6 minutes:

wow i dont know that why the smiling objects apear in the code!

Hello Smithjim,
I am trying to repeat the result based on the paper 'Negative index bulk metamaterials at terahertz frequencies' too. But somehow I could not get the same result as the paper. Is there any possibility you send me your design, or give me some guidence? Thank you very much.
Joy

Hi
would you please send a paper in physical review.
"Causality of double-negative metamaterials"
physical review E,vol. 68 , 026615

Hi guys,
Please any1, who have information and idea baout my project . please help ne out .....

My project 'ELECTROMANETIC INDUCTION IN METAMATERIALS'

To integrate Helmholtz equation in meta-material waveguide using PDE tool solver using MATLAB software.
Considering the Snell’s law for an electromagnetic wave propagating from air to a meta-material.
Calculating the refracted beam angle with respect from normal to the surface.
Using Simulation in MATLAB,
Observing the design and propagation of EM wave in normal and concave meta-material.
Calculating the focal length, its spot size.

Dear smithjim

I tried to download your attached file, but after downloading, it can not be opened! the file size is only 448B! so would you please upload it again?

Thanx alot

clear
clf

c=3e8;

load s11.mat
load s21.mat

f=f*1e12;%frequency
k_0=2*pi*f/c;
d=69e-6;%thickness


s11=s11(2,:).*exp(-i.*s11(3,:)*pi/180);
s21=s21(2,:).*exp(-i.*s21(3,:)*pi/180);


z=sqrt( ( (1+s11).^2 - s21.^2 )./( (1-s11).^2 - s21.^2) );

eink0d=s21./(1-s11.*((z-1)./(z+1)));
for p=1:length(s11)
if abs(eink0d(p))>1
z(p)=-z(p);
eink0d(p)=s21(p)./(1-s11(p).*((z(p)-1)./(z(p)+1)));
end
end
figure(1)
plot(f*1e-12,real(z))
hold on
plot(f*1e-12,imag(z),'r')
hold off

n=-i.*log(eink0d)./k_0./d;
figure(2)
plot(f*1e-12,real(n))
hold on
plot(f*1e-12,imag(n),'r')
hold off

smithjim
plz re-upload ur CST file, the current file has a wrong extension! tanx

I got the results. refer to:
https://www.edaboard.com/viewtopic.p...257454#1257454

Myebook, your results were somehow deleted. Can you post your results to this blog post? Thanks.