Dual-band filtering antenna with independent predetermined frequencies and low cross-polarization levels

In this paper, a dual-band filtering antenna with independent predetermined frequencies and low crosspolarization levels is proposed. In order to realize the independent control of frequencies of two radiation passbands, multiple additional structures such as rectangular slots, rectangular parasitic patches, and U-shaped slots are integrated on the traditional rectangular patch antenna to introduce new resonant modes and radiation nulls to the antenna, simultaneously. Since the generation structures of each frequency point are different, they do not affect each other. Besides, to obtain low cross-polarization levels, each additional structure is carefully adjusted such that the current vectors of each resonant frequency along the cross-polarized direction are quite weak. The proposed antenna operates in the 5G sub-6G (4050-4294 MHz) and the Wi-Fi 5.8 GHz band (5700-5920 MHz), and achieves cross-polarization levels of -37.8 and -36.8 dB in the lower and higher frequency bands, respectively. Compared to other multi-band filtering antennas, the proposed one has the advantages of independent predetermined frequencies and lower cross-polarization levels.