A broadband circularly polarized stacked microstrip patch antenna with parasitic elements

Abstract

In this article, a wideband circularly polarized stacked microstrip patch antenna (CP SMPA) with continuous phase feed characteristics is presented. The designed antenna consists of a square-loop feeding structure as driven element, four rectangular-patches and four rotated square-patches as parasitic elements. First, a square-loop with arc-shaped strip is designed to obtain 90° phase difference. Second, four rectangular-patches are placed next to the square-loop for generating a CP resonant mode through a capacitive coupling method. Third, four rotated square-patches are arranged at the top of the rectangular-patches to excite an additional CP resonant mode. Eventually, the designed CP SMPA features a wide −10-dB impedance bandwidth (IBW) of 32% (5.93 GHz, 4.98–6.88 GHz), and a broad 3-dB axial ratio bandwidth of 22.8% (6.15 GHz, 5.45–6.85 GHz).