Open AccessMiniaturised multi‐beam‐controlled circular eight‐port beamforming network for long‐range UHF RFID hemispheric coverage
Author(s) -
Jeong MinGyo,
Kim JiHong,
Bae SangHyeon,
Lee WangSang
Publication year - 2018
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2017.0416
Subject(s) - ultra high frequency , beamforming , beamwidth , beam (structure) , materials science , antenna array , antenna (radio) , optics , engineering , electrical engineering , electronic engineering , physics
In this paper, a miniaturised multi‐beam‐controlled circular eight‐port beamforming network for long‐range ultra‐high‐frequency radio‐frequency identification (UHF RFID) hemispheric beam‐coverage systems (e.g. unmanned aircraft systems) is proposed. For multi‐beam control and compact implementation, the proposed eight‐port feeding network consists of an integrated beam‐control block with a two‐stage RF switch block, 12 quadrature hybrid couplers, and 12 90° phase shifters, and was designed and fabricated on a circular three‐layer 1.2 mm FR‐4 substrate. The diameter of the fabricated network is ∼0.47 λ 0 at 915 MHz. The measured maximum insertion loss, and amplitude and phase imbalances of the fabricated network at the authorised UHF RFID frequency band (902–928 MHz) are ∼4.5 dB, ± 1.3 dB, and ± 17.5°, respectively. An eight‐element dipole antenna array with the proposed feeding network shows feasibility of hemispheric beam coverage by generating multiple beams simultaneously regarding port controls. Beam coverages, where the simulated realised gain is higher than 3 dBi, are ∼180° and 130° at ϕ = 90 and 0°, respectively.