28-GHz High-Selectivity Bandpass Filters With Dual-Behavior Resonators Using GaAs Technology

In this article, the design and implementation of two 28-GHz millimeter-wave on-chip high selectivity bandpass filters with coupled dual-behavior resonators are proposed. The proposed bandpass filters consist of coupled dual-behavior resonators with open/shorted stubs. Two and three out-of-band transmission zeros can be realized for the two bandpass filters. Two on-chip millimeter-wave bandpass filters are designed and fabricated for verification. The measurement results show that the insertion losses are both less than 2.2 dB at the center frequency. The sizes of the designed filters are 2.556 mm ×1.23 mm and 3.155 mm × 1.47 mm, respectively, including the pad.