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Coupling Coefficient K For a Resonator Filter

version 1.0 (5.59 KB) by

This function calculates the coupling coefficient of a resonator filter based on the scattering para

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K = FindK(filename)

This program uses the SBOX
(S-parameter toolbox) by "Tudor Dima".
Specifically (SXPParse.m and Phrase2Word.m)

The toolbox is an EXCELLENT interface for manipulation of Scattering
Parameter files in Matlab.

This function will read in a Touchstone file (.snp) and calculate
a quantity K. The function finds the two highest peaks in |S21|.
The frequency of the first peak (lower frequency) is called F_low.
The frequency of the second peak (high frequency) is called F_high.

K =

This formula is from the Daniel G. Swanson Jr. article entitled
"Narrow-Band Microwave Filter Design. The article was found in the October 2007 IEEE Microwave Magazine.
The formula is on page 108.

This program was written in response to a question posted by member
"junz" on the Sonnet Community Forum (

Comments and Ratings (3)




Sadik (view profile)

mr bitter

MATLAB Release
MATLAB 7.6 (R2008a)

Inspired by: S-parameter toolbox (+ Z, Y, H, G, ABCD, T)

Download apps, toolboxes, and other File Exchange content using Add-On Explorer in MATLAB.

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