Dual Circular Polarization with Reduced Mutual Coupling Among Two Orthogonally Placed CPW-Fed Microstrip Antennas for Broadband Applications

Abstract

In this communication, a design of Coplanar Waveguide-fed Dual Circularly Polarized Broadband Antenna (CPW-DCPBA) has been proposed. Here, a square slot consists of two orthogonal T-shaped asymmetric microstrip antennas protruded from a signal line of CPW feed has been presented. The microstrip antennas are isolated with an inverted-L type grounded strip embedded at the left corner, followed by a square strip. A modified meandered line (MML) is embedded with the square strip to achieve circular polarization at the lower frequency. An SRR is placed at the back of the antenna to enhance the 3-dB axial ratio bandwidth (ARBW). Measurements of the fabricated antenna show an impedance bandwidth of 88% and the 3-dB ARBW of 75%, in which return loss is better than 10 dB and the isolation among the antennas are better than 15 dB. A peak gain of 3.1–5.6 dBi is achieved within the axial ratio band. The antenna is fabricated on FR-4 substrate of 60 mm × 60 mm × 1.6 mm with an antenna area of 0.359λ 0 2 . The simulated results are in good agreement with the measured results which verified its usage for broadband applications.