S-Shaped Metasurface-Based Wideband Circularly Polarized Patch Antenna for C-Band Applications

Abstract

This research proposed an S-shaped metasurface (MTS)-based wideband circularly polarized (CP) patch antenna for C-band uplink frequency spectrum. The proposed MTS-based CP patch antenna was of low profile and fabricated on three substrate layers: upper, middle, and lower. The upper substrate contained 4 × 4 periodic S-shaped MTS elements, the middle substrate functioned as ground plane with a rectangular-shaped slot at the center, and the lower substrate contained a coplanar waveguide with microstrip and ground. The S-shaped MTS elements converted linearly polarized (LP) into CP wave. Simulations were performed, and an antenna prototype was fabricated and experiments carried out. The measured impedance bandwidth and axial ratio bandwidth (ARBW) at the center frequency of 5.9 GHz were 43.22% (4.05 -6.6 GHz) and 22% (5.3 -6.6 GHz), respectively, rendering the proposed antenna suitable for satellite communication applications. The proposed antenna achieved the maximum gain of 6.16 dBic at 5.6 GHz. The novelty of this research lies in the use of S-shaped MTS elements to efficiently convert LP into CP wave and achieve wider ARBW for the C-band uplink spectrum.

Low-Profile Wideband Unidirectional Circularly Polarized Metasurface-Based Bowtie Slot Antenna

“…14 Table I compares the performance of the proposed antenna with that of other unidirectional antenna designs described in the literature. The selection criteria of the [15] and [17]- [21] comparison tables was based on comparing our design's size, impedance bandwidth, AR bandwidth, and gain to previous state of arts which used single radiating element LP source and an LP to CP polarization conversion metasurfaces which was stacked above the radiator. Our proposed antenna shows a wide impedance bandwidth, wide 3-dB AR bandwidth, and low profile compared with the other aforementioned antennas [15], [17]- [21].…”

“…Recently, various linear-to-circular wave conversion structures have been investigated in metasurface CP antenna design [15]- [21]. In [15], the authors used 16 unit cells in a 4 × 4 metasurface layout, with each unit cell having a rectangular loop with a diagonal microstrip for LP to CP wave conversion.…”

“…Thus, the simultaneous enhancement of AR bandwidth and reduction in antenna size is still challenging, and many studies are being conducted to address these issues. Some researchers have proposed techniques to improve AR bandwidth and impedance bandwidth using different types of metasurface patches, but they use extremely thick substrates [20]- [21]. In [20], a CP slot antenna was proposed using a corner-truncated metasurface for polarization conversion.…”

“…In [20], a CP slot antenna was proposed using a corner-truncated metasurface for polarization conversion. An S-shaped metasurface polarization converter for LP to CP wave conversion was presented in [21]. Both antennas achieved wide impedance and AR bandwidths.…”

“…A prominent way of increasing the bandwidth of a slot antenna is by increasing the width of a rectangular slot [36] or a bowtie slot [37], [38]. In all previous works, with polarization converters using slot antennas as an LP source [16]- [21], the authors employed narrow-width slot antennas. Even though they employed wideband circularly polarized metasurface patches, they obtained narrow impedance and AR bandwidths.…”