Title :
Bidirectional radiated circularly polarised square-ring antenna for portable RFID reader
Author :
Lin, Yeou-Fu ; Chen, Hou-Ming ; Chu, F.-H. ; Pan, S.-C.
Author_Institution :
Inst. of Photonics & Commun., Nat. Kaohsiung Univ. of Appl. Sci., Kaohsiung
Abstract :
A novel single-layer, dual-fed technique for a bidirectional radiated circularly polarised square-ring antenna operated in the UHF band is presented. The two feed ports of the square-ring radiating element are placed in orthogonal directions and connected to a feeding network with a Wilkinson power divider in the same plane. Properly adjusting the size of the capacitive coupling groundplane results in good impedance matching and circularly polarised radiation, and a broad impedance bandwidth (S 11 les -10 dB) of about 45.2% and a 3 dB axial-ratio bandwidth of about 8.7% were obtained.
Keywords :
UHF antennas; antenna feeds; antenna radiation patterns; directive antennas; impedance matching; polarisation; power dividers; radiofrequency identification; UHF band operation; Wilkinson power divider; bidirectional radiated circularly polarised square-ring antenna; capacitive coupling groundplane; dual-fed technique; impedance matching; portable RFID reader;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:20082579
