A tunable and reconfigurable active filter based on distributed structure concept

The filter presented in this article is an active band-pass filter which center frequency and bandwidth can be tuned. It is composed of channels inserted into a distributed structure, and the frequency agility is obtained by activating one or more of them. The concept is validated with measurements realized on a 3-channel prototype structure implemented in a PPH25 GaAs technology. This filter is tunable throughout the X and Ku bands. This first prototype yields encouraging results: the center frequency can be tuned between 9.7 and 14 GHz, with an average gain of 10 dB throughout this range. The filter occupies 13.5 mm² of area and consumes 10.5 mA per active stage from a 4V supplying voltage. It is designed for wideband and agile receivers.