A Singly Fed Dual-Beam Switchable Array Antenna for Unmanned Aerial Vehicles

A singly fed $2\mathrm{x}2$ array antenna for beam-switching applications is proposed. The antenna has a very simple structure and comprises four antenna elements and a phase-shift keying (PSK) modulator. With the aid of an in/anti-phase signal com-bination of the antenna elements, the proposed structure can generate two distinct beams, i.e., sum and difference radiation patterns. The necessary phase shifting of the input signals fed to the antenna elements is accomplished by the binary PSK modulator, which consists of two switching PIN diodes. Therefore, radiation beams can be changed between sum and difference radiation patterns by switching PIN diodes. The antenna designed for 10 GHz shows a 10-dB impedance bandwidth of 3% with a gain of more than 8.5 dBi. A prototype antenna is fabricated to validate the concept. Besides, simulated and measured radiation patterns are compared, and both show good agreement.