A Pattern Reconfigurable Quasi-Yagi Antenna Array for 3-D Full-Space Coverage

In this paper, a pattern reconfigurable quasi-Yagi antenna and array for 3-D full-space coverage is proposed. The antenna element consists of hook-shaped radiating patches, parallel-coupled branches, a circular metal patch, and a windmill-shaped metal ground, where four diodes are integrated with the feed lines. By switching the diodes' operation states, the antenna element can operate in both omnidirectional and directional modes. In the omnidirectional mode, the antenna exhibits a bandwidth of 5.02-5.89 GHz, with a maximum gain of approximately 0.8 dBi. While in the directional mode, the antenna provides a bandwidth of 4.93-5.81 GHz and a maximum gain of 2.4 dBi. In array configuration, directional pattern reconfiguration for azimuth and elevation planes for 3-D full-space coverage can be achieved through excited elements selection and diode states switching, with a peak gain of 4.9 dBi in the directional mode and a pattern non-circularity of 3.1 dB in the omnidirectional mode. The proposed antenna offers advantages such as compact size, light weight, and excellent omnidirectionality, which has great potential in the application of unmanned aerial vehicles (UAVs).