A 24 GHz microstrip grid array antenna excited by coaxial-fed slot

Abstract

A microstrip grid array antenna excited by coaxial-fed slot on Rogers 5880 substrate is reported. The antenna has a volume of 70 × 70 × 1.041mm. The coaxial-fed slot is 0.2-mm offset from the middle of the ground plane to obtain symmetrical patterns and a cavity is added below the slot to increase the front-to-back ratio. Simulation results in HFSS indicates that the antenna has a 10-dB impedance bandwidth of 1.12 GHz from 23.76 GHz to 24.88 GHz and a 3 dB gain bandwidth of 1.68 GHz from 23.52 GHz to 25.2 GHz with the maximal peak realized gain of 20.57 dBi at 24.72 GHz. This work demonstrates that compared with capacitive slot, coaxial to slot transition is a more effective method to excite microstrip grid array antenna.