Design quad-band monopole antenna using coupling effect of rectangular ring-shaped patches and slots on the ground plane

A quad-band monopole antenna for DCS1800, PCS1900, WCDMA, WLAN, and Mobile WiMAX applications is proposed. The proposed antenna consists of two rectangular ring-shaped radiators and two different size of L shaped slots on the ground plane. Using the dual rectangular ring radiators, two frequency bands obtained and the coupling effect occurred in gaps between two rectangular ring patches, the optimized matching characteristic is obtained. By adding two slots on the ground plane, the dual resonant frequency bands can be obtained. The proposed antenna is fabricated and measured. For the measured results, -10 dB return loss bandwidths are 1200 MHz (1600 to 2800 MHz), 800 MHz (3200 to 4000 MHz), 300 MHz (5140 to 5440 MHz), and 690 MHz (5560 to 6250 MHz), respectively.