Design of a Compact Quad-Band Hybrid Antenna for Compass/WiMAX/WLAN Applications

A compact quad-band hybrid antenna for Compass/WiMAX/WLAN applications is proposed. The hybrid antenna is designed based on the method of combining a composite right/left-handed transmission line (CRLH-TL) unit cell with a meandered monopole and wide multi-band characteristics are achieved by merging some of resonance frequencies of the CRLH-TL unit cell and meandered monopole together. Coplanar waveguide (CPW) is used as a parallel excitation for both the CRLH-TL unit cell and meandered monopole. A prototype of the proposed hybrid antenna has been constructed and experimentally studied. The measured results show that four distinct operating bandwidths with 10 dB return loss are about 30 MHz (1.25-1.28 GHz), 290 MHz (2.44-2.73 GHz), 650 MHz (3.17-3.82 GHz) and 1130 MHz (5.03-6.16 GHz), covering the Compass B3, 2.5/3.5/5.5 GHz WiMAX and 5.2/5.8 GHz WLAN bands. Furthermore, the antenna has a single-layer planar structure with a small volume of only 31 × 21 × 2 mm. Acceptable radiation patterns and peak realized gains are obtained over the operating bands.