An aperture-coupled linear microstrip leaky-wave antenna array withtwo-dimensional dual-beam scanning capability

This paper describes an X-band 4×1 aperture-coupled series-fed electronically steerable microstrip leaky-wave antenna (LWA) array design, which has dual-beam radiation pattern and two-dimensional (2-D) beam-scanning capability. The LWA array is operated in the first higher order mode and excited by center-fed aperture coupled for dual-beam operation. The varactor-tuned phase shifters are placed between the antenna elements. The measured half-power beamwidth of the H-plane and quasi-E-plane radiation patterns are less than 30°. By tuning the reverse dc bias of the varactor diodes, the main beam can be scanned in azimuth plane from -13° to +13° off broadside. In the elevation plane, the beam-scanning angle is close to 20° as the operating frequency tuned from 11.58-12.5 GHz. Taking into account each phase-shifter insertion loss and phase progression, the measured results compared closely with the theoretical prediction. The proposed antenna array is suitable for wireless communication and collision warning radar systems