Compact Multimode Beamforming Antenna for Space-Division Multiple Access Application

In this letter, a multimode antenna for adaptive space-division multiple access (SDMA) application is proposed. The antenna merges a monopole-like radiator and a multimode resonant cavity into a compact structure. The amplitudes of three orthogonal modes are separately controlled by three ports in the cavity. By tuning the excitation power ratio and phase (only 0°/180° is needed) at the three ports, the antenna pattern continuously scans across 360° in the H-plane. This controlling scheme makes both analog and digital beamforming easier and supports base station SDMA scenarios. The simulation and measurement results show the antenna has good scanning performance. The design is proved to be a good candidate for high throughput wireless communication systems, especially the miniaturized Internet of Things base station applications.