Matlab Codes_s parameter to transmission line parameters

Consider two structures in cascade


I wil name the combined structure as C.

I have the s-parameters for the structure A and for the overall structure C. I want to extract the s-param for the structure B. i need to use matlab for the purpose.

The technique i have chosen is to convert S-param to transmission param (or ABCD param), since for a cascaded structure like above the ABCD parameters would be

[Tc]=[Ta][Tb]

where Tc=transmission param for combined structure
Ta=transmission param for structure A
Tb=transmission param for structure B

to find Tb i can do the following computations:
[Tc][Ta]-1=[Tb]

So in the maTLAB code attached below, i have taken the s2p (sparam file) for structure A, converetd it to t param( infact the ABCD param), then taken the s2p file for C and multiplied both matrices. the end result is converted back to s-param file, since i want my answer in s-param. Please note that the matrices used here are 3D matrices.

i have written the code but the answers are wrong. there are no errors. but the answers are not matching with the s-param i have for structure B. Can neone plz help?

it doesnt matter if the code is slow etc. All i want is the correct ans.




file = 'C:\Users\abc\A.s2p';
h = read(rfdata.data,file); % Read s-param file containing the s-param for structure A into data object.
[outmatrix, freq] = extract(h,'S',50); %extracting s-param from the file
abcd_params_h = s2t(outmatrix); %converting to ABCD param

a=abcd_params_h

for j=1:127
bi=inv(a,:,j));

eval(['A' num2str(j) '=bi']);

end

%where A1, A2 etc are the inverse of transmission param for the test structure and have to be multiplied with the transmission param for total structure
% c=cat (3,A1,A2,A3,A4,A5);


file2 = 'C:\Users\abc\C.s2p';
h1 = read(rfdata.data,file2); % Read s-param file containing the s-param for structure C into data object
[outmatrix1, freq] = extract(h1,'S',50); %extracting s-param from the file
abcd_params_h1 = s2t(outmatrix1); %converting

b=abcd_params_h1;

for j=1:127
bi=(b,:,j));

eval(['B' num2str(j) '=bi']);

end
%where B1, B2 etc are the transmission param for the total structure and
%have to be multiplied with the inverse transmission param generated above using
%outmatrix

% c=cat (3,B1,B2,B3,B4,B5)


C1=A1*B1

C2=A2*B2

C3=A3*B3

C4=A4*B4

C5=A5*B5

C6=A6*B6

C7=A7*B7

C8=A8*B8

C9=A9*B9

C10=A10*B10

C11=A11*B11

C12=A12*B12

C13=A13*B13

C14=A14*B14

C15=A15*B15

C16=A16*B16

C17=A17*B17

C18=A18*B18

C19=A19*B19

C20=A20*B20

C21=A21*B21

C22=A22*B22

C23=A23*B23

C24=A24*B24

C25=A25*B25

C26=A26*B26

C27=A27*B27

C28=A28*B28

C29=A29*B29

C30=A30*B30

C31=A31*B31

C32=A32*B32

C33=A33*B33

C34=A34*B34

C35=A35*B35

C36=A36*B36

C37=A37*B37

C38=A38*B38

C39=A39*B39

C40=A40*B40
C41=A41*B41

C42=A42*B42

C43=A43*B43

C44=A44*B44

C45=A45*B45

C46=A46*B46

C47=A47*B47

C48=A48*B48

C49=A49*B49

C50=A50*B50

C51=A51*B51

C52=A52*B52

C53=A53*B53

C54=A54*B54

C55=A55*B55

C56=A56*B56

C57=A57*B57

C58=A58*B58

C59=A59*B59
C60=A60*B60

C61=A61*B61

C62=A62*B62

C63=A63*B63

C64=A64*B64

C65=A65*B65

C66=A66*B66

C67=A67*B67

C68=A68*B68

C69=A69*B69

C70=A70*B70

C71=A71*B71

C72=A72*B72

C73=A73*B73

C74=A74*B74

C75=A75*B75

C76=A76*B76

C77=A77*B77

C78=A78*B78

C79=A79*B79

C80=A80*B80

C81=A81*B81

C82=A82*B82

C83=A83*B83

C84=A84*B84

C85=A85*B85

C86=A86*B86

C87=A87*B87

C88=A88*B88

C89=A89*B89
C90=A90*B90

C91=A91*B91

C92=A92*B92

C93=A93*B93

C94=A94*B94

C95=A95*B95

C96=A96*B96

C97=A97*B97

C98=A98*B98

C99=A99*B99

C100=A100*B100

C101=A101*B101

C102=A102*B102

C103=A103*B103

C104=A104*B104

C105=A105*B105

C106=A106*B106

C107=A107*B107

C108=A108*B108

C109=A109*B109

C110=A110*B110

C111=A111*B111

C112=A112*B112

C113=A113*B113

C114=A114*B114

C115=A115*B115

C116=A116*B116

C117=A117*B117

C118=A118*B118

C119=A119*B119

C120=A120*B120

C121=A121*B121

C122=A122*B122

C123=A123*B123

C124=A124*B124

C125=A125*B125

C126=A126*B126

C127=A127*B127




outmatrix2=cat (3,C1,C2,C3,C4,C5,C6,C7,C8,C9,C10,C11,C12,C13,C14,C15,C16,C17,C18,C19,C20,C21,C22,C23,C24,C25,C26,C27,C28,C29,C30,C31,C32,C33,C34,C35,C36,C37,C38,C39,C40,C41,C42,C43,C44,C45,C46,C47,C48,C49,C50,C51,C52,C53,C54,C55,C56,C57,C58,C59,C60,C61,C62,C63,C64,C65,C66,C67,C68,C69,C70,C71,C72,C73,C74,C75,C76,C77,C78,C79,C80,C81,C82,C83,C84,C85,C86,C87,C88,C89,C90,C91,C92,C93,C94,C95,C96,C97,C98,C99,C100,C101,C102,C103,C104,C105,C106,C107,C108,C109,C110,C111,C112,C113,C114,C115,C116,C117,C118,C119,C120,C121,C122,C123,C124,C125,C126,C127)

%now we have obtained the transmission parameters for B structure only
%and we have to convert it to s-param and get the s2p file from which we
%can plot curve etc

s_params_h2 = t2s(outmatrix2); %converting

txdata = rfdata.data;
txdata.S_Parameters = outmatrix2;
txdata.Freq=freq
write(txdata,'C:\Users\abc\B.s2p')

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somebody plz help