# Odd Mode Analysis: Microwave Transmission Line

1. Mar 20, 2014

### sandy.bridge

Hey all,

Refer to page 5 in the pdf in the link (http://whites.sdsmt.edu/classes/ee481/notes/481Lecture26.pdf)

I am having a little bit of a hard time understanding a portion of a derivation. You will notice that when determining the ABCD paramters of the shunt stubs they merely use A=1, B=0, C=Y, D=1. However, they do not use A=1, B=Z, C=0, D=1 for the 1/4λ transmission line (which would be used to describe a series impedance). Why can they treat the stubs as an impedance when determining the ABCD parameters, but the 1/4λ wave section has to be treated as transmission line? They are both sections of transmission line, but the stub can be treated as a lumped element?

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2. Mar 20, 2014

### sandy.bridge

To be honest, I think I figured it out. Not entirely sure why my brain was not functioning properly when I was analyzing this. Series and shunt stubs can be represented as lumped elements. The two stubs are shunt to the 1/4 wave tranmission line, and hence can be represented as lumped elements shunt to the 1/4 wave transmission line.

My apologies!