Wideband U-slot microstrip patch antenna array

Abstract

The design and measured results of a wideband antenna array of four U-slot rectangular patches are presented. The U-slot patches are proximity coupled by a microstrip feed line terminating with novel Π-shaped stubs. By using a foam layer of thickness t ~ 5.5 mm as the supporting substrate, an impedance bandwidth (SWR ≤ 2) of 27% ranging from 3.4 GHz to 4.5 GHz is achieved. It has an average gain of 13 dBi and a cross-polarisation of less than –20 dB.