Title :
Compact microstrip antenna with forward-directed radiation pattern for RFID reader card
Author :
Weigand, Steven M.
Author_Institution :
WJ Commun. Inc., San Jose, CA, USA
Abstract :
This paper presents a compact microstrip antenna that is compatible with PCMCIA-compatible UHF RFID reader cards. The small form factor (0.15λ×0.10λ×0.002λ) results in relatively narrow bandwidth (2% for VSWR<2) but reasonable directivity (2 dBi) in the forward direction, which is of primary importance for the maximum read-range of backscatter RFID-readers. Being a balanced antenna, the radiation pattern and input impedance are less sensitive than unbalanced antennas to hand-effects or nearby metal objects. Simulated and measured data is presented that identifies the basic properties of the antenna. Additionally, fundamental geometric dependencies are discussed.
Keywords :
UHF antennas; antenna radiation patterns; directive antennas; electric impedance; microstrip antennas; radiofrequency identification; PCMCIA-compatible RFID reader cards; UHF RFID reader cards; VSWR; backscatter RFID-readers; compact antenna; directivity; form factor; forward-directed radiation pattern; hand-effects; input impedance; microstrip antenna; read-range; Antenna radiation patterns; Bandwidth; Coplanar transmission lines; Dipole antennas; Directive antennas; Impedance; Microstrip antennas; Radiofrequency identification; Shunt (electrical); UHF antennas;
Conference_Titel :
Antennas and Propagation Society International Symposium, 2005 IEEE
Print_ISBN :
0-7803-8883-6
DOI :
10.1109/APS.2005.1552011
