Microstrip-fed quasi-Yagi antenna featuring compact characteristics

In this paper, a compact quasi-Yagi antenna consisting of uniform-impedance director, stepped-impedance driven dipole and stepped-impedance reflector is presented. Compared with the conventional uniform-impedance dipoles, the proposed stepped-impedance dipoles achieve 31% length reduction. The measured 10-dB bandwidth is 28% at the center frequency of 2.6 GHz, and the antenna gain varies within the operating band is from 2.6 dBi to 4.2 dBi. Also, a 10-dB front-to-back ratio is obtained.