A dual-mode wide-band bandpass filter using slotted patch resonator with tuning stubs

In this paper, a dual-mode wide-band bandpass filter using slotted patch resonator with tuning stubs is introduced as an alternative for the miniaturization of the filter structure. The microstrip loop resonator consists of four identical patches with attached to inner corner of the square loop. The bandpass filter is based on the bandstop filter employing direct-connected feed lines on the orthogonal of the microstrip loop resonator. The introduction of two tuning stubs connecting opposite to the ports widens the passband and sharpens the stopbands.