A Novel Broadband Circularly Polarized Antenna for UHF RFID Technology

摘要

A novel UHF broadband circularly polarized antenna based on RFID technology is designed. The antenna structure can be divided into four levels. The radiation unit and the parasitic patch are composed of two corner truncated patches which have the similar shape but different sizes. Archimedes gradient belt and probe are used to feed, which effectively expand the bandwidth. At the same time, the design of 3 air medium layers as well as the parasitic unit makes a contribution to the bandwidth too. The simulation and optimization results of the software HFSS.15 show that the impedance bandwidth and the axial ratio bandwidth can achieve 745MHz to 977MHz and 830MHz-930MHz respectively. When antenna works at the center frequency of 884MHz, the gain is 8.66dB. After physical production and processing test, by comparing the measured and the simulated results, a conclusion could be drawn that the antenna reaches the expected effect and has certain practical value among the error range.