Compact Multilayer Bandpass Filter with Modified Hairpin Resonators

Compact selective bandpass filter, based on the Rhodes approximation, is proposed using the novel modified hairpin resonators realized on a double-sided microstrip. The equivalence is presented between the hairpin resonator realized on a single-sided microstrip and the modified hairpin resonator realized on a double-sided microstrip. The footprint area of the filter is reduced by 50% with the multilayer realization. The proposed design methodology is exemplified by a fourth-order multilayer bandpass filter, which is fabricated and measured. The simulated and measured results are in agreement.