A novel design of broadband Quasi-Yagi antenna loaded with split-ring resonators

A novel broadband Quasi-Yagi antenna is presented. The antenna is feed by a microstrip line. A new balun structure is used to realized transform from microstrip line to coplanar strip line. It has a radiator and two directors, the ground plane at the bottom of the substrate act as reflector. The bandwidth is relatively broad. To enhance the gain, two group of split-ring resonators (SRR) is loaded on the front of the directors. The -10dB return loss bandwidth of the improved antenna reached 53.7%(5.9-10.2Ghz), 5.7~9.3dB gain is attained, about 2dB more than the prototype antenna. Both the prototype antenna and the improved antenna are fabricated and measured. The measured results agree with the simulated ones.