A NOVEL CPW-FED PLANAR MONOPOLE ANTENNA WITH BROADBAND CIRCULARLY POLARIZATION

A novel CPW-fed planar printed monopole antenna with broadband circular polarization (CP) characteristic is presented. The proposed antenna consists of a copper coin-shaped patch (CCSP) and an asymmetrical ground plane. To achieve a broadband CP wave, a vertical stub is added to the CCSP to produce orthogonal surface currents for right-hand circular polarization (RHCP). The design of the CCSP greatly increases the impedance bandwidth (IBW) of 89.2% which can cover the whole CP bandwidth of 71% completely. The measured results show that the proposed antenna has not only a broad 3-dB AR bandwidth (ARBW) of 71% (3900 MHz, 3.1–7 GHz) with respect to the CP center frequency 5.8 GHz, but also a wide 10-dB return loss bandwidth of 89.2% (5040 MHz, 2.16–7.2 GHz) centered at 5.65 GHz.