Wide Band Dual-Beam U-Slot Microstrip Antenna

Abstract

A wide band dual-beam microstrip antenna is proposed in this communication. Two radiation beams off broadside are obtained by operating the patch antenna at the higher order TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> mode instead of the fundamental mode, which radiates a broadside beam. Broadening the antenna bandwidth is achieved by using the U-slot technique. Unlike previous work on the conventional U-slot microstrip antenna, the effect of the U-slot inclusion on the performance of a patch antenna operating at the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> mode is studied across the entire achieved bandwidth. The antenna analysis is carried out with the aid of full wave simulation, and an antenna prototype is fabricated and measured for validation. Good agreement between the simulated and measured results is observed. The antenna operating frequency range is 5.18-5.8 GHz with VSWR less than 2, which corresponds to 11.8% impedance bandwidth. It exhibits two radiation beams, directed at 35° and -33° with 7.92 dBi and 5.94 dBi realized gain, respectively at 5.5 GHz.