Design of wideband bandpass filter with reconfigurable bandwidth using cross-shaped resonator

This paper proposed a wideband bandpass filter with reconfigurable bandwidth using a cross shaped resonator. The proposed resonator has wide passband which can be used to implement a wideband bandpass filter. Moreover, the fractional bandwidth of this filter is only related to the characteristic impedance of the resonator stubs, using two sets of diodes can achieve the fractional bandwidth tuning from 68% to 120% when the center frequency is fixed at around 6.8GHz.