Interdigital Filters

This is an inheritantly bandpass filter created from an array of mutually coupled lines. the design can vary from a bunch of circular TEM lines in a box to a planar design of coupled lines on microstrip. Since this site is orientated to high power filters we look a the rods in a box. Based upon Nicholson approach.

Interdigital Diagram

Design Specification


Height: the internal box height.

End spacing; the distance to the box wall from the outer rod centre.

Aim to get the rod diameter to height ratio for a Zeven, Zodd either side of Zo