Isolators and Circulators The major filtering mechanism used in RF and microwave filters is selective matching: • The filter presents an input and output match in the passband • The filter mismatches...

Isolators and Circulators The major filtering mechanism used in RF and microwave filters is selective matching:

• The filter presents an input and output match in the passband

• The filter mismatches the input and output in its stopband.

In general, we don’t like mismatched components in systems. Mismatches cause many subtle problems in mixers and oscillators, so we try to avoid them if possible. How would you build a filter that presents a broadband match over its passband and its stopband?