Ultra‐high‐frequency wideband circularly polarized crossed‐dipole antenna with wide axial‐ratio beamwidths for SATCOM applications

Abstract

Abstract In this study, an ultra‐high‐frequency (UHF) wideband circularly polarized (CP) crossed‐dipole antenna with wide axial‐ratio beamwidth (ARBW) is proposed for SATCOM applications. The antenna is composed of two pairs of dipoles with umbrella‐shaped arms, and they are fed by a feeding network to generate CP radiation. Two pairs of parasitic patches are introduced symmetrically between the dipole arms and the ground plane. Due to coupling of the dipoles, currents can be induced on to the metal patches, which can not only decrease the antenna volume by increasing the current path of the dipole arms, but also additional radiation can be provided to enhance the ARBW. A prototype of proposed antenna was fabricated and measured. The measured results indicate that it operates at the UHF band ranging from 280 to 420 MHz, with a –10‐dB impedance bandwidth of 40.5% and a 3‐dB AR bandwidth of 42%. Furthermore, the antenna exhibits a 3‐dB ARBW of more than 190°within a wide operating band of 23.1%.