Size reduction of circularly polarized slot antenna using open C-slot for WiMAX application.

A new wideband circularly polarized (CP) open C-slot antenna fed by a microstrip line for size reduction is presented. The proposed antenna consists of an open C-slot with a straight slit on the ground plane, and a microstrip line with a semicircle-shaped patch on the other side of the substrate. The antenna size is reduced by about 35% compared with the circular slot antenna. By using the semicircle-shaped patch to disturb the magnetic current distribution on the open C-slot, a wider CP bandwidth can be achieved. The measured results show that the proposed antenna can provide a 3 dB axial ratio (AR) bandwidth of 40% (4.1–6.2 GHz) and a 10 dB return loss impedance bandwidth of 107% (2.3–7.6 GHz). The measured gain variation is from 2.8 to 4.3 dBic in the 3 dB AR bandwidth. A prototype of the proposed antenna has a simple and compact size of 30 × 55 × 1.6 mm3. [ABSTRACT FROM AUTHOR]