A low profile broadband circularly polarized planar antenna with an embedded slot realized on a reactive impedance surface

A low profile and broadband slotted microstrip patch antenna on reactive impedance surface (RIS) is proposed as a circularly polarized (CP) planar antenna. The proposed structure consists of metallic via, complementary Landolt C-shape slot loaded patch antenna and a 7 x 7 array of rectangular RIS. The inductive RIS, having magnetic energy storing ability, is utilized to achieve miniaturization and enhancement of circular polarization bandwidth (CPBW). The 3-dB CPBW is further increased by using metallic via and embedding a complementary Landolt C shape slot in the second quadrant of the patch. A fabricated prototype was developed that has an overall size of 61.5 mm x 57 mm x 4.08 mm (0.984 lambda(0) x 0.912 lambda(0) x 0.0652 lambda(0) at 4.8 GHz). Measured and simulated results are in good agreement. The measured 3-dB-axial ratio (AR) bandwidth of the proposed antenna is 28.9% (4428-5815 MHz). The. measured impedance bandwidth is 46.52% (3743-5976 MHz), which covers WLAN, Wi-Max and 5G communications. The antenna radiates left-handed CP wave at boresight direction with realized gain ranging from 5.3 to 6.8 dBic within the 3-dB AR bandwidth. (C) 2019 Elsevier GmbH. All rights reserved.