Messing with Substrates (10 GHz bandpass filter) [silly]

In this post we will take a reasonable 10 GHz bandpass filter (at least for a new grad student) and see how a new substrate will change how this filter works.

This is the original bandpass filter with the standard substrate:



If you can read the numbers on the above pic, you could also build this filter. Let’s get a better picture of what the substrate is for the original circuit:



Let’s try a silicon dielectric, shall we?


One thing is for sure – it’s not a bandpass filter anymore.messybpsilicon2


Let’s add a 20 mil Indium conductive layer below the dielectric:


Voilà! It’s centered at 8 GHz! Brilliant!



Here’s a thought – how well does your bandpass filter work underwater?


It looks like your bandpass filter might give you a little gain there at some frequencies in water!messybpwater2