Haipin Filter 50 ohm Feed

Hi guys,

Im doing some studies on hairpin filter design. im interested to know the impact of length of 50ohm feed line on hairpin filter to the performance of the filter. How do i determine the max or minimum length of the 50ohm feed line?

thanks

-danesh-

The length of the interconnecting 50 ohm lines has no impact on filter performance - if the filter is well matched to 50 ohms.

The critical part is the 50ohm line connecting to the resonator.
The above picture shows a thin line connecting 50 ohm line and the resonator.
Some designs will not use this impedance transformer.

This is interesting -- I've not seen one with a series transformer before. Usually you just select the tap point (based on J.s. wong paper for instance). Using a transformer might give you a nice degree of freedom since the geometry of your resonator may actually keep you from tapping at the 50 ohm point!

Lance

You are right,
To correct the sentence
" Using a transformer might give you"
should be
" Using a transformer will give you"