Novel compact ultra-wideband bandpass filter based on vialess vertical CPW/microstrip transitions

摘要

A novel compact ultra-wideband (UWB) bandpass filter based on vialess vertical coplanar waveguide (CPW)/microstrip transitions is proposed, designed, fabricated and measured. The represented filter consists of two back-to-back hybrid microstrip/slotline transitions derived from the microstrip to CPW. Due to this coupling configuration, a smooth UWB passband response with an insertion loss <;0.85 dB is achieved. Moreover, two transmission zeros at lower and upper passband edges are introduced to provide sharp selectivity. For verification, a prototype is fabricated and measured. The simulated results are in good agreement with the measured one.