Optimization of noise performance for various topologies of microwave active recursive filters

This article deals with the improvement of the noise figure for three topologies of microwave active recursive filters. We show how, using a noise wave formalism , the noise factor of these filters can be effectively minimized by using appropriate unbalanced power dividers/combiners and an amplifier. A comparison between the different topologies is given. We start from measured results and validate our approach with simulated examples.