A Compact Microstrip CP Antenna Using Slots and Defected Ground Structure (DGS)

Abstract

A Compact circularly polarized coaxially fed slotted microstrip patch with Defected Ground Structure (DGS) is proposed in this paper. DGS is introduced to increase the effective current path length and miniaturize the antenna. Microstrip patch size is reduced by 40% using the proposed DGS and slots. Two pairs of asymmetrical slots are etched parallel to the edge of microstrip patch and is coaxially fed along the diagonal to obtain circular polarization. An axial ratio of 0.4dB is achieved at L5 band (1.175GHz). Further a ring is cut around the feed to match the antenna input impedance. Proposed antenna of size 35mmx35mmx1.27mm is fabricated and 10dB return loss bandwidth of 8MHz is achieved. Design, development and results of the antenna are presented.