Single layer proximity fed microstrip patch antenna for circularly polarized dual band wireless applications

A single layer proximity fed circularly polarized microstrip antenna for dual band applications is presented. A cross shaped slot with asymmetric dimensions is present on the radiating element with an X-shaped strip embedded along the cross slot for feeding the square patch. In the proposed design, two pairs of circular slots are loaded orthogonally on the square patch. The suggested circular slots excite two orthogonal waves equal in amplitude and with 90 degree phase difference for circular polarization without cutting any portion of the patch. The antenna dimensions are optimized considering the effect of different radius of the circular slot. The antenna dimension is 80 mm × 80 mm × 1.6 mm. The designed antenna has -10 dB reflection coefficient bandwidths of 3.2-3.9 GHz in the first band and 4.9 GHz to 5.6 GHz in the upper second band. The axial ratio bandwidth lies from 3.3-3.4 GHz in the lower band and an upper band from 5.4 GHz to 5.6 GHz.