Inter-Digital filter for an ADS-B receiver

Update 2. I believe I have found an improvement for the 5-6 dB loss in the passband. It involves improving the electrical conduction between the frame and the covers. It will require a slight change in the cover design as well as in the height of the frame. I am also trying some rectangular resonators to widen the bandwidth slightly. A rectangular resonator is also easier to print smoothly lying on its side where it is not as sensitive to any z-banding. (if that is a problem). I still have to print the updated revisions of the new parts to test though. Hopefully by the end of April. It will be revision 1 of the filter.


Update 1. I am still trying to find a way to get rid of the 5-6 dB loss in the passband. Unless you have a cell tower closeby this filter is not recommended for immediately after the antenna at this point. However, if you have preamp and want to ensure that only the 1090MHz get to your SDR by adding it after the pre-amp, then it should work. Just ensure that your