A Wide-Angle Scanning Leaky-Wave Antenna Based on a Composite Right/Left-Handed Transmission Line

This paper presents a frequency-independent, wide-angle scanning leaky-wave antenna (LWA), based on the composite right/left-handed transmission line (CRLH TL). The proposed LWA consists of a coplanar waveguide-grounded (CPWG) structure loaded by varactors. Loaded varactors are used to control the phase constant of the fundamental mode of the LWA by adjusting the applied DC voltage. The LWA has an excellent wide-angle scanning capability, a simple structure, and low cost. Results show that the main beam of an LWA with 20unit cells can scan from -66 degrees to 62 degrees at the operation frequency of3.0 GHz, with a peak gain of 9.9 dBi, and a gain fluctuation of less than 4.9 dB. The operation bandwidth and radiation efficiency are about 13% and over 50%, respectively. A 10-unit cascaded LWA prototype was designed, fabricated, and measured to verify the design concept.