Matching Networks on Narrowband Multistage Low Noise Amplifier (LNA)
Microwave amplifiers are tricky. Fets and transistors have so strong internal leakage from output to input that the result is easily an oscillator. Matching networks are needed for stability. Even a single stage amp can be an oscillator with mismatched signal source or load. Another reason for matching is to avoid wasting all gain to the attenuation caused by reflections. Generally also noise optimization is tried as the term LNA suggests and in wideband applications some gain equalization can be needed. The circuit is a compromise between different requirements.

Wideband amp is surely more complex because everything should work in the whole operating band, calculations at the center frequency alone do not provide useful results.