A new electronically tunable combline filter with simultaneous continuous control of central frequency and bandwidth

A new reconfigurable band pass filter with electronically continuous control of both central frequency and bandwidth is presented in this paper. The bandwidth tuning is achieved by means of an ingenious method to modify the electrical couplings of the filter resonators. The propose structure employs varactor capacitors as variable reactance elements. Finally, a filter prototype is designed, constructed and measured in suspended stripline technology in the UHF band (470-862 MHz).