Axial Ratio and Gain Enhancement of a Circular-Ring Slot Antenna Using a Pair of Asymmetrical Rectangular Slots and a Parasitic Patch for a Radio Beacon on a Nanosatellite

Peberlin Parulian Sitompul,Josaphat Tetuko Sri Sumantyo,Mohammad Nasucha,Farohaji Kurniawan

doi:10.3390/aerospace6040039

Peberlin Parulian Sitompul, Josaphat Tetuko Sri Sumantyo + Show 2 more

Open Access

https://doi.org/10.3390/aerospace6040039

Copy DOI

Abstract

Radio beacons enable measurements of ionospheric radio scintillations and total electron content (TEC). These beacons transmit unmodulated, phase-coherent waves in S-band frequencies. Many satellite applications require circularly polarized (CP) wideband antennas. Their compact size, lightweight, and simple fabrication method make CP antennas suitable for small satellite systems. The slot antenna has wideband impedance, but the 3 dB axial ratio bandwidth (ARBW) is narrower compared to the impedance bandwidth (IBW). In this paper, a circularly polarized circular-slotted antenna (CSA) is proposed to enhance the ARBW and the antenna gain. A pair of asymmetrical rectangular slots, a simple 50 Ω feedline and a parasitic patch were introduced to a CSA to enhance the 3 dB ARBW and the antenna gain. Rectangular slots were inserted on the diagonal axis of the CSA, the feedline was shifted to the left side of the x-axis, and a parasitic patch was attached to the circular slot. The lengths of the rectangular slots correspond to the resonant frequency, and the parasitic patch width corresponds to the higher frequency of the 3 dB ARBW. The asymmetrical rectangular slots, the shifted feedline, and the parasitic patch successfully improved the measured 3 dB ARBW of the antenna by 787.5 MHz or 35.79%. The measured gain of a CSA with left-hand circular polarization (LHCP) was also improved by shifting the feedline and the rectangular slot, achieving a peak gain of 5 dBic.

Highlights

IntroductionSensing (CEReS), Chiba University in Chiba, Japan has been conducting research and development related to ionosphere sensors onboard microsatellites since 2015 [1,2]
The Josaphat Microwave Remote Sensing Laboratory (JMRSL), Center for Environmental RemoteSensing (CEReS), Chiba University in Chiba, Japan has been conducting research and development related to ionosphere sensors onboard microsatellites since 2015 [1,2]
The goal of this study was to create a design for enhancing the circularly polarized (CP) performance of a circular-slotted antenna (CSA) to achieve a wide 3 dB axial ratio bandwidth (ARBW) close to its impedance bandwidth (IBW), and a higher gain

Summary

Introduction

Sensing (CEReS), Chiba University in Chiba, Japan has been conducting research and development related to ionosphere sensors onboard microsatellites since 2015 [1,2]. Developments in space technology have motivated scientists and engineers to consider the idea of a small satellite. The evolution and ongoing miniaturization of technology have led to the emergence of new small satellites, such as nanosatellites capable of performing simple and complex missions in outer space [3]. As a radio wave transmitter and receiver, an antenna is a critical part of a satellite system. Satellite communication systems, require wideband circularly polarized (CP) antennas. The CP antenna is resilient to multi-path interferences, the Faraday rotation effect, and polarization mismatch, especially for small satellites without attitude and stabilization control

Objectives

Results

Conclusion