High gain and circularly polarized substrate integrated waveguide cavity antenna array based on metasurface

Two substrate integrated waveguide(SIW) cavity antenna arrays based on metasurface are proposed in this paper. By rotating the metasurface element, circularly polarized and high gain antennas are achieved respectively. Firstly, multi-mode resonance theory is employed to broaden the bandwidth of the slot antenna. And then, an SIW cavity composed of 4×4 cornercut elements is added on the top of the slot antenna to achieve the circular polarization and improve the front-to-back ratio. Thirdly, the metasurface elements are sequentially rotated and a high gain antenna with 2-dBi enhancement on average in the operation band is obtained. Based on the two antenna units, two 2×2 antenna arrays are designed. The circularly polarized and high gain antenna arrays are both fabricated to verify the correctness. Furthermore, the novel wideband phase shifter is employed in the circularly polarized antenna to obtain an operating bandwidth of 38%(4.05 GHz–5.95 GHz)and AR bandwidth of 24.9%(4.4 GHz–5.65 GHz). The bandwidth of the high gain antenna can reach 42.7%(3.95 GHz–6.1 GHz) and with the gain enhancement of 2 dBi compared with that of the circularly polarized antenna. The gain remains steady in most of operating band within a variation of 1 dBi. It is remarkable that the rotating of the metasurface element has a great influence on the antenna performance, which provides a new explication for the multi-function antenna design.

A dual-polarized Fabry-Pérot antenna with high gain and wide bandwidth for millimeter-wave applications

We introduce a dual-polarized(DP)Fabry–Perot cavity(FPC)antenna operating at the millimeter-wave(mmWave)frequency band with high-gain and wideband characteristics.A DP feeding source and a partially reflective surface(PRS)integrated with a Fresnel zone lens are suggested to realize dual-polarization wave radiation over a wide impedance bandwidth.The feeding source provides vertical and horizontal polarizations while keeping high isolation between the two polarizations.PRS is used to realize Fabry cavity to produce a directive beam radiation.The integrated Fresnel zone rings are introduced for phase correction,leading to a significant gain enhancement for the antenna.For verification,a 60-GHz FPC antenna prototype with DP radiation is designed and fabricated with measurement results.It consists of a feeding source,a PRS integrated with a Fresnel zone lens,a quasi-curved reflector,and four three-dimensional printed supporters.The results illustrate that the peak gains of vertical and horizontal polarizations are 18.4 and 17.6 dBi,respectively.The impedance matching bandwidth for the two polarizations is 14%.The performance ensures that the proposed DP FPC antenna is a promising candidate for the fifth-generation wireless communication systems in the mmWave band.