Dual circularly polarised omnidirectional antenna. Issue 6 (26th March 2019)

• Record Type: Journal Article
• Authors: Wang, Ankang; Li, Xi; Yi, XiangJie; Yang, Lin; Zhao, Jiawei; Li, Aiqin
• Is Part Of: IET microwaves, antennas & propagation. Volume 13:Issue 6(2019)
• Page Start: 870
• Page End: 873
• Publication Date: 2019-03-26
• Subjects: coaxial cables -- wireless LAN -- omnidirectional antennas -- UHF antennas -- broadband antennas -- microstrip antennas -- electromagnetic wave polarisation -- strip lines -- antenna radiation patterns -- antenna feeds -- dipole antennas; feed ports -- dual circularly polarised omnidirectional antenna -- in‐phase current loop -- printed dipole -- feed network -- zero‐phase‐shift line -- parallel strip line -- optimised antenna -- CP characteristics -- right‐hand CP -- complex feed structure -- left‐hand CP -- antenna radiation far‐field -- omnidirectional CP radiation mode -- noise figure 3.0 dB -- noise figure 10.0 dB -- frequency 260.0 MHz -- frequency 255.0 MHz -- frequency 2.45 GHz -- frequency 2320.0 MHz to 2570.0 MHz -- frequency 2340.0 MHz to 2595.0 MHz; Microwaves -- Periodicals; Microwave antennas -- Periodicals; Antennas (Electronics) -- Periodicals; Radio wave propagation -- Periodicals; Microwave communication systems -- Periodicals; 621.381305
• DOI: 10.1049/iet-map.2018.5933
• Languages: English
• ISSNs: 1751-8725

Abstract

Abstract : A dual circularly polarised (CP) omnidirectional antenna is proposed. The antenna consists of an in‐phase current loop, a printed dipole and a feed network. The in‐phase current loop formed by zero‐phase‐shift line is placed orthogonally to the printed dipole to produce Eφ and Eθ components in the far‐field of antenna radiation. By adjusting the amplitude and phase of Eθ and Eφ, good CP characteristics can be formed. A simple and feasible 3 dB coupler can realise the switching between the left‐hand CP (LHCP) and right‐hand CP (RHCP) without additional complex feed structure. Furthermore, the structure of the parallel strip line to the microstrip can effectively eliminate the unbalanced current of the coaxial cable. Finally, the optimised antenna was processed and measured. The measured results show that the impedance bandwidth (| S 11 |<−10 dB) is 260 MHz (2320–2570 MHz) and 255 MHz (2340–2595 MHz) at two feed ports, respectively. It is worth mentioning that the antenna has a simple structure and a good omnidirectional CP radiation mode in the 2.45 GHz WLAN band.