A Dual-Band Dual-Polarized Antenna With High Aperture Reuse Efficiency and Large Frequency Ratio for Modern Wireless Communications

In this letter, a microwave dense dielectric patch antenna and a millimeter-wave (MMW) Fabry-Perot cavity (FPC) antenna are first combined to implement a dual-band dual-polarized antenna with high aperture reuse efficiency and large frequency ratio. In the proposed design, a piece of high-permittivity dielectric and a metallic patch are adopted as not only the radiators of the microwave antenna but also the partially reflective surface and ground plane of theMMWFPC. Furthermore, for performance improvement, the high-permittivity dielectric is sharpened to widen the FPC gain bandwidth, a neutralization line is used to enhance the polarization isolation, and two small capacitive disks are employed to improve the channel isolation. As a demonstration, the proposed antenna is designed at 3.5 and 27 GHz. A prototype is fabricated and achieves 20% bandwidth (VSWR< 1.5 and isolation> 30 dB) with 8 dBi gain in the low band, 22% bandwidth (VSWR<2 and isolation>24 dB) with 19.9 dBi gain in the high band, and channel isolation higher than 40 dB.