DUAL-BAND DUAL-SENSE CIRCULARLY POLARIZED SQUARE SLOT ANTENNA WITH CHANGEABLE POLARIZATION

This article presents a two-port coplanar waveguide fed dual-band and dual-sense circularly polarized square slot antenna having polarization changing capability. The antenna has asymmetric H-shaped feed lines, and a T- shaped grounded stub in orthogonal direction of feed lines. Two bands having opposite sense of circular polarization are obtained by proper selections of dimensions of feedlines and grounded stub. Moreover, the sense of circular polarization of the bands can be changed by changing the port of excitation. Measured circular polarized bandwidths are obtained as 16.72% (1.48-1.75 GHz) at lower band and 4.7% (3.4-3.57 GHz) at upper band with AR <= 3 dB. The measured return loss is better than10 dB at both the bands. The measured isolation varies from 11 to 17.3 dB at lower band and 18-21.3 dB at upper band. (C) 2017 Wiley Periodicals, Inc.