Chiral Dielectric Metasurfaces for Highly Integrated, Broadband Circularly Polarized Antenna

High-Gain Dual-Polarization Microstrip Antenna Based on Transmission Focusing Metasurface

In this paper, a single-feed microstrip antenna (MA) equipped with a transmission-mode focusing metasurface (MS) is proposed to achieve dual-polarization capabilities and superior high-gain radiation performance. The original-feed MA comprises two distinct layers of coaxial-fed tangential patches, enabling it to emit a circular polarization (CP) wave with a gain of 3.5 dBic at 5.6 GHz and linear polarization (LP) radiation with a gain of 4 dBi at 13.7 GHz. To improve the performance of the single-feed MA, a dual-polarization transmission focusing MS is proposed and numerically substantiated. By positioning the originally designed MA at the focal point of the MS, we create a transmission-mode MS antenna system capable of achieving CP and LP radiations with the significantly higher gains of 12.9 dBic and 14.8 dBi at 5.6 GHz and 13.7 GHz, respectively. Measurements conducted on the fabricated dual-polarization focusing MS antenna closely align with the simulation results, validating the effectiveness of our approach. This work underscores the significant potential of dual-polarization high-speed data systems and offers a practical solution for enhancing antenna gains in contemporary wireless communication systems.

Gain Enhancement and Cross-Polarization Suppression of Cavity-Backed Antennas Using a Flared Ground Cavity and Iris

Herein, we present new design principles for gain enhancement and cross-polarization suppression in dual-polarized cavity-backed antennas and demonstrate the capability in an octagonal cavity-backed open prism antenna (OCROP). In our approach, the gain is enhanced through an optimal flaring procedure and a novel metallic iris is used to control the electromagnetic fields and thereby reduce the cross-polarization. Previously, we investigated a dual-polarized OCROP antenna configuration and were able to simultaneously achieve 50% impedance bandwidth, 40% cross-polarization bandwidth (≤25 dB), and 10.2 dBi peak gain. In this study, we investigated gain enhancement by flaring an upper section of the ground cavity sidewalls, while maintaining a constant cavity height. Two cases were investigated: (1) the flare angle was modified, while the ratio of the non-flared to flared sidewall heights was kept constant, and (2) the ratio of the non-flared to flared sidewall heights was varied. In case 1, we established that, while increasing the flare angle results in a gain increase, there is a limit, as cross-polarization at the upper operating frequencies increases. In case 2, we were able to reduce the aperture phase error and achieve a higher peak gain of 12.8 dBi. To address the increased cross-polarization at the high frequency end when a large flare was used, we added a metallic iris at the junction of non-flared and flared sidewalls. We showed that increasing the iris width generally decreases the cross-polarization at high frequencies, without compromising the gain and impedance bandwidth. At an optimal width, it provides a nearly constant, low cross-polarization (below -25.8 dB) and a peak gain of 13.3 dBi, across the entire 50.7% impedance bandwidth of the antenna. We fabricated and successfully tested a prototype to verify the design and simulation approach. These results prove that incorporating an aperture flare with a metallic iris can significantly improve the gain and cross-polarization performance of cavity-backed antennas.

Mechanical stress induces a scalable circularly polarized LEO satellite antenna with Quadrifilar spiral

This paper investigates a left-hand circularly polarized (LHCP) antenna and a right-hand circularly polarized (RHCP) antenna on LEO Satellite, which is based on the phase-tuning metasurface. We overcome its inherent limitations in size, weight and power, and designed a high-gain, ultra-lightweight, scalable antenna for small satellite communications. The antenna can generate continuous and large tunability of subwavelength, with low-Q resonators. The simulated and experimental results verify that different capacitance and inductance modes can be effectively generated by rotating the spiral arms of single-arm spiral antennas with corresponding degrees, which greatly simplify the feeding network. The maximum gain of the normal position within the angle of the uplink and downlink is 4~9 dBi higher than that of the ordinary polarized antenna. In addition, the design method proposed to this article is superior to the reference system in terms of impedance bandwidth, axial ratio bandwidth, and operation frequency. The performance achievements of this paper are implemented within the bandwidth of 3 MHz of uplink and downlink, such as impedance bandwidth is 3 MHz with impedance of 50, axial ratio bandwidth is 2.5 MHz, operation frequency of uplink is 240-243 MHz, downlink is 320 MHz and 401 MHz, and the voltage standing wave ratio (VSWR) is less than 2 dB which is so called S parameter, the above parameters can meet the performance index design requirements.

Editorial: Special Issue "Antenna Design for 5G and Beyond"

The demand for high data rate transfer and large capacities of traffic is continuously growing as the world witnesses the development of the fifth generation (5G) of wireless communications with the fastest broadband speed yet and low latency [...].