aaron_do
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Hi all,
I designed a simple microstrip line on PCB for a circuit, and in the measurement, I noticed there is a periodic dip in the insertion loss. So I ran a simulation using ADS momentum, and noticed the same effect (see attachment). Note that this is insertion loss calculated as |S21|2/(1-|S11|2)
When I make the line shorter, the dip moves to higher frequencies. Does anybody know why this periodic dip is occuring?
thanks, Aaron
EDIT: Seems to be because the ground plane is too narrow. Does anybody know any guidelines on how large the ground plane should be?
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