Design of very‐low‐profile circular UHF small antenna using characteristic mode analysis. Issue 8 (19th May 2017)

• Record Type: Journal Article
• Authors: Gao, Yue; Ma, Runbo; Zhang, Qianyun; Parini, Clive
• Is Part Of: IET microwaves, antennas & propagation. Volume 11:Issue 8(2017)
• Page Start: 1113
• Page End: 1120
• Publication Date: 2017-05-19
• Subjects: UHF antennas -- antenna radiation patterns -- monopole antennas -- antenna feeds -- eigenvalues and eigenfunctions -- equivalent circuits -- cables (electric); very‐low‐profile circular UHF small antenna design -- very‐low‐profile circular ultra‐high frequency small antenna design -- characteristic mode analysis -- radiating body -- fundamental mode analysis -- ground planes -- CMA -- magnetic feeding loop -- equivalent circuit -- antenna bandwidth -- eigen value -- modal significance -- circular antenna -- testing cable -- compact sensors -- machine‐to‐machine application -- Internet‐of‐Things application -- frequency 474 MHz; Microwaves -- Periodicals; Microwave antennas -- Periodicals; Antennas (Electronics) -- Periodicals; Radio wave propagation -- Periodicals; Microwave communication systems -- Periodicals; 621.381305
• DOI: 10.1049/iet-map.2016.0826
• Languages: English
• ISSNs: 1751-8725

Abstract

Abstract : This study presents a very‐low‐profile circular ultra‐high frequency (UHF) small antenna with a radiating body transformed from a monopole. The proposed radiating body is gradually improved by analysing fundamental modes of the structure with different ground planes via characteristic mode analysis (CMA). CMAs demonstrate operating principles of the radiating body so that a magnetic feeding loop is proposed to excite the radiating body. An equivalent circuit of the radiating body and magnetic feeding loop is then established. The relationships between antenna bandwidth, and eigen value and modal significance are derived through physical insight of the CMA. A prototype of the proposed circular antenna operating at 474 MHz is fabricated and measured. It has a radius of 5.2%λ c (λ c is the operating wavelength), and a profile of 5.2%λ c The CMA of the proposed antenna with testing cable at different lengths is applied to understand the discrepancy between simulations and measurements. The analysis and performance evaluation shows that the proposed antenna can be a strong contender for compact sensors for machine‐to‐machine and internet of things applications.