Q> Manufacturable Iris-Coupled Waveguide Filter

[jcpascua]

I've read the paper entitle "Direct Coupled Resonator Filters" by S.B. Cohn which outlines how to design such filters. I've been able to design a simple 1st order filter using the described procedure using infinitesimally thin conductors.

Now, I want my filter to be fabricated. As such, I had to set the conductors to finite thicknesses. So I simulated the model with finite conductor thickness and discovered that the finite iris thickness has a great effect on the response of the filter. Is there any paper out there which accounts for the effect of the finite iris thickness and has design procedures for such?

I don't know how it's being done in the industry. Do I have to tune the filter first (by adjusting iris opening and/or iris spacing) after I've set the finite thickness of the conductors? Or can I go directly to placing tuning screws and just have the tuning once its fabricated?

Additionally, how do I place the tuning screws? Where are the "tactical" places to position them?

I'd really appreciate help. Thanks in advance

 

[biff44]

I would buy a used one on ebay, take it apart, and learn how to manufacture it.

Yes, you do need to be able to tune it after assembly. But you need to assemble it repeatably enough to get it into tuning range. Also, you have to use high Q materials and solders. Poor soldering can easily add 3 dB of insertion loss.