Design and Analysis of a Compact GSM/GPS Dual-Band Bandpass Filter Using a T-Shaped Resonator

This study presents an ultracompact dual-band bandpass filter with controllable transmission zeros based on quarter-wave dual-mode resonator for GSM (global system mobile communications) and GPS positioning system) wireless applications. The is made up of two resonators, which help to independently control the passbands. A direct feed creates first operating band, serves as a feeding source interior operates at higher frequency band. Therefore, pair can be energized between passbands, high roll-off skirts are obtained. To reduce size entire filter, resonators bent connected together through hole in metal base. structure symmetrical nature, so both bands obtained using even-odd mode analysis method. For applications, center working band 850 MHz, while second 1.57 GHz. Although there line (λg waveguide length MHz), has been simulated fabricated verification, ultra-compact 0.10 λg × 0.09 (0.0095 2). simulation results measured match well, theory design concept recognized.