Flexible RF one-chip active filter based on recursive architecture in UHF range

This paper reports development of an integrated tunable active filter for lower UHF band based on the recursive architecture and its application. The recursive filter core gives the 2-pole bandpass response, and its center frequency can be tuned from 270 to 850 [MHz]. The auto setting mechanism was developed for the filter center frequency and passband width. Higher order filters were synthesized by combining multiple cores.