Bandwidth Enhancement of Asymmetric Coplanar Waveguide (ACPW)-Fed Antenna Based on Composite Right/Left-Handed Transmission Line

A novel wideband antenna based on composite right/left-handed transmission line (CRLH-TL) is presented. The bandwidth enhancement of the antenna can be achieved when the zeroth-order and first-positive-order modes are closely spaced and merged together. The uniplanar asymmetric coplanar waveguide (ACPW) is adopted as the host transmission line. The ACPW structure not only offers the design freedom to implement the circuit parameters, but also overcomes the design constraint of the traditional CPW. The measured results show that the operating bandwidth is 1720 MHz (2.1-3.82 GHz), corresponding to approximately 58.1% fractional bandwidth. Owing to the characteristics of wide bandwidth, enhanced efficiency, and omnidirectional radiation, the proposed antenna is a good candidate for modern wireless communication systems (LTE, WLAN, WiMAX).