A compact dual-frequency antenna with triangular ring monopole and U-shaped sleeves

A compact coplanar waveguide (CPW)-fed dual-band antenna is presented. The proposed antenna comprises of a triangular ring monopole and two attached sleeves for two dual-band operation. By modifying the ground plane, a broadband dual-frequency operation is achieved for the proposed antenna. The antenna has a simple planar structure and occupies a small size about of 28 × 35 mm², including the finite ground CPW feeding mechanism. Experimental results show that, the impedance bandwidths, determined from 10-dB return loss, of the two operating frequencies are 24% (2.2-2.8 GHz) and 59.8% (3.4-6.3 GHz), and good monopole-like radiation characteristic over the operating bands have been obtained.