A Dual-band Filtering Antenna with Different Polarizations over Two Bands

A dual-band filtering antenna with different polarizations over two bands is proposed for the first time. The proposed antenna consists of a via-loaded circular patch on the bottom substrate and two circular patches on the top and middle substrates. For better filtering characteristics, a coupled-fed mechanism is introduced to generate two radiation nulls and the feeding probe is extended to achieve the good suppression within the middle band. Measured results show that the proposed dual-band filtering antenna achieves a CP overlapping bandwidth of 9.2% (2.28 ~ 2.5 GHz) over the lower band and a LP bandwidth of 4.7% (5.13 ~ 5.38 GHz) over the upper band. Flat in-band gain responses and skirt frequency selectivity can be found for the two operating frequency bands, demonstrating the excellent performance as a filtering antenna.