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.
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!