Low-Profile Antenna System for Cognitive Radio in IoST CubeSat Applications

• Published in: Sensors (Basel, Switzerland) Vol. 23; no. 10; p. 4782
• Main Authors: Aljaloud, Khaled, Sultan, Kamel, Ikram, Muhammad, Alqahtani, Ali H, Abbasi, Qammar Hussain, Hussain, Rifaqat
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 16-05-2023; MDPI
• Subjects: Antenna design; Antennas; Antennas (Electronics); Capacitors; Circular polarization; Cognition & reasoning; Cognitive ability; Cognitive radio; Communication; Cubesat; CubeSats; Design; internet of space things; Loop antennas; Narrowband; Radiation; reconfigurable antenna; Reconfiguration; Satellites; Slot antennas; UHF band; Ultrahigh frequencies; Varactor diodes; Very high frequencies; UHF band; cognitive radio; reconfigurable antenna; CubeSats; internet of space things
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s23104782

Since the CubeSats have become inherently used for the Internet of space things (IoST) applications, the limited spectral band at the ultra-high frequency (UHF) and very high frequency should be efficiently utilized to be sufficient for different applications of CubeSats. Therefore, cognitive radio (CR) has been used as an enabling technology for efficient, dynamic, and flexible spectrum utilization. So, this paper proposes a low-profile antenna for cognitive radio in IoST CubeSat applications at the UHF band. The proposed antenna comprises a circularly polarized wideband (WB) semi-hexagonal slot and two narrowband (NB) frequency reconfigurable loop slots integrated into a single-layer substrate. The semi-hexagonal-shaped slot antenna is excited by two orthogonal +/-45° tapered feed lines and loaded by a capacitor in order to achieve left/right-handed circular polarization in wide bandwidth from 0.57 GHz to 0.95 GHz. In addition, two NB frequency reconfigurable slot loop-based antennas are tuned over a wide frequency band from 0.6 GHz to 1.05 GH. The antenna tuning is achieved based on a varactor diode integrated into the slot loop antenna. The two NB antennas are designed as meander loops to miniaturize the physical length and point in different directions to achieve pattern diversity. The antenna design is fabricated on FR-4 substrate, and measured results have verified the simulated results.