DESIGN AND FABRICATION OF DUAL BAND RFID ANTENNA USING HYBRID COUPLER WITH CSRR

Abstract

Nowadays wireless communication devices are flourishing. The performance of the wireless devices must be improved and should have small size and less weight. There are many miniaturization techniques to enhance the characteristics and it gathered a widespread concentration. Microstrip patch antenna is widely used as it has better performance such as higher bandwidth, virtuous efficiency. This paper proposes design of dual band circularly polarized (CP) patch antenna with incorporation of branch line coupler with complementary split ring resonator (CSRR). The design has aperture coupled feeding technique designed for UHF and ISM band. FR-4 substrate is used for the proposed antenna. The relative permittivity of the FR-4 substrate is 4.6 and thickness of 1.6 mm which has greater design flexibility, reduced weight, low cost. The branch line coupler is evaluated in terms of S-parameters. Moreover, the antenna with the dual band coupler with separate transmit and receive ports is evaluated in terms of its impedance bandwidth, isolation, antenna gains, and axial ratios. The results showed that the coupler has good return loss and isolation loss characteristics. The proposed structure covered the band of 900 MHz and 2.4 GHz which can be used for UHF and RFID applications.