Metasurface-Based Circularly Polarized Slot Antenna for X-band Applications

Abstract Circularly polarized slot antennas are now widely used in wireless systems due to their low profile, ease of integration, low cost, and high impedance bandwidth. A low-profile circularly polarized slot antenna with high impedance, wide axial ratio bandwidth (ARBW), and high gain in the X-band is proposed in this work. The antenna structure consists of 11 rectangular patch elements, a microstrip-fed line, a coplanar waveguide (CPW) with vias, and a rectangular etched slot on the ground plane. The fed line is coupled with the metasurface (MTS) to generate CP radiations. The proposed antenna array was designed and measured with an overall size of 0.4λ 0 × 0.4λ 0 × 0.12λ 0 at 10 GHz. The measured reflection coefficient (|S 11 | ≤ −10dB) yielded an ARBW of 10.62-11.87 GHz (11.12%) and an impedance bandwidth (IBW) of 8.92-10.52 GHz (16.01%). Moreover, the proposed MTS-based antenna array also realizes a broadside maximum gain of 5.85 dBic. The proposed antenna is designed to be high-performing, simple, low-profile, and easy to design.