Compact microstrip patch UHF-RFID tag antenna for metal object

Abstract

A compact microstrip patch ultra-high-frequency (UHF) RFID tag antenna mountable on metal object is proposed in this paper. The antenna, which has a very simple structure without any shorting pin and shorting plate, is composed of meander feed line, rectangular loop and double T-match structure. The insertion of ground plane in the tag antenna design reduces the negative impact of metal objects to the performance of the tag antenna. The tag with the overall dimension of 58 × 34 × 0.85 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> is designed to operate in Malaysia frequency range with the center frequency of 921 MHz. The performance of the tag is evaluated through simulation and measurement in terms of impedance matching, S-Parameter and tag reading range. From measurement, the tag reading range obtained is 2.8 m in free air, while on metal object is 2.0 m.