A Sum-difference Beam Reconfigurable Microstrip Patch Antenna

keywords:sum-difference beam antenna  patch antenna  sidelobe reduction  high gain  TM03 mode

Abstract:A single-layer square slotted microstrip patch antenna working in TM03 mode with reconfigurable sum-difference beams is designed in this paper. The antenna is fed by a coaxial probe without complex sum-difference network and feed structure. Three parallel-arranged rectangular slots on the top radiation patch are used for sidelobe reduction and gain enhancement of the sum beam pattern. Eight metal vias on both sides of the slot are used to generate the difference beam. A simple diode switch control circuit is designed on the bottom metal floor to realize the switching between the sum beam and the difference beam. The measured results show that the center operating frequency of the sum-difference beam antenna is 3. 53 GHz, the impedance bandwidth of -10 dB is 1. 4%, the gain of the sum beam is 11. 35 dBi, the sidelobe level is -22. 9 dB, the half power beamwidth is 45°, the gain of difference beam is 9. 62 dBi, and the null depth is -17. 95 dB. The proposed sum-difference beam reconfigurable slotted microstrip patch antenna has compact structure, low profile, high gain, good radiation characteristics, and is easy to integrate with other planar circuits on PCB.