Dual Circularly Polarized Stacked Patch Filtenna Without Quadrature Coupler or Extra filters

Dual polarized filtennas are considered as key components in communication systems. In this paper, a dual circularly polarized (CP) stacked patch filtenna without quadrature coupler or extra filters is proposed. High port isolation is ensured by adopting a stacked patch. Based on the analysis of the equivalent circuit, two T-shaped transmission line networks are added to the feedlines and two radiation nulls at the two sides of the passband are generated. A passband of 3.4-3.6GHz and a bandpass filtering response are achieved.