UHF RFID 리더기용 원형편파 안테나 설계

Abstract

The Radio Frequency Identification(RFID) system is a sort of Automatic Identification. Using a reader, transponder and antenna etc, it identifies the information of transponder by means of a contactless reading and radio frequency. In this thesis, Circular Polarization Antenna of UHF band for RFID reader will be presented about design and manufacturing. In a distant range, to perceive the signal from a number of RFID tag simultaneously without errors, Hybrid Coupler(Insertion Loss 0.16㏈) has been used to devide original signal into two signals which have 90° phase contrast and two of those signals are supplied to λ/2 length of Stripline Antenna. Also, Antenna Radiation Efficiency have been maximized by using the two signals which have 90° Phase contrast and designing Radiation panel(Cross section 13.4㎠) having two Feed point for embodying Circular polarization. In the result of this measurement, Return Loss(S11) was very low (914㎒ ~ -45.529㏈) and Antenna Gain has the commercialized level of Gain (6.09㏈i). In addition, it have found that those antennas could be applied to other RFID systems through the Impedance Matching (Transmission line matching method using Microstripline). Also, Circular Polarization Antenna was improved to increase Receiving Sensibility and perceive a number of signals from tags precisely. This kind of access method is expected to contribute to future study of Circular Polarization Antenna for RFID reader in terms of it's compatibility with other systems and improvements of the Antenna Efficiency.