Lossless Diode Switch in RF Filter
This client makes radios for military aircraft. For that reason, we can't go into details beyond this: the tier-1 supplier sent back an RF anti-jamming filter since it was too noisy. Our client (tier-2) identified the failure point, and gave us the task of designing and validating a new DC-biased diode switch inside their filter.
A large and understated part of this project was sourcing the military-grade components that would be necessary to meet the rigorous standards: our requirements for noise, weight, and cost were very tight. Blocking high frequency noise was naturally our toughest constraint, since radio signals had to pass through the filter losslessly while blocking outside interference.
Regular electronics vendors failed our client on the first try, and we had to source from a scientific components company for extremely low-loss and impedance matched diodes, inductors, connectors, etc.
We had to test these components very precisely as well, there had to be no sign of the signal losses that the tier-1 had identified. We soldered the components on in-house, we put the new filter under a series of RF stress tests and tests designed to compare the noise floor of a clean sample signal to one originating in an already-noisy environment.
Our new filter passed these tests beautifully to our and our client's satisfaction. The client ordered parts for our filter in production quantity and is using them today.