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 the MMW FPC. 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.