Multibeam Microstrip Leaky-Wave Antenna Array for Passive 2-D Scanning in the 5 GHz Wi-Fi Band

A compact planar multibeam antenna array for two-dimensional (2-D) beam scanning in the 5 GHz Wi-Fi ISM band, is presented. The array is composed of four half-width-microstrip leaky-wave antennas (HWM-LWA) that are interconnected by 4W4 microstrip Butler matrices. By combining the frequency beamscanning response of the LWAs and the beamforming mechanism of the Butler matrices, the synthesis of 32 directive beams using 4 channels of the Wi-Fi band is demonstrated. A wide scanning range from –60: to +60: along the elevation plane is achieved using a narrow frequency band from 5.18 GHz to 5.72 GHz, and a scanning range from –45: to +45: in the perpendicular plane through beam switching. Compared to other multibeam antennas in previous literature, this novel topology shows the most compact planar design, while offering the widest 2-D scanning range in such narrow scanning bandwidth.