Wideband Printed Quasi-Yagi Antenna Using Multiple Modes Technique

A design approach for wideband planar printed quasi-Yagi antenna is proposed based on multiple modes technique in this paper. Different with other methods, which use wideband feeding structures, the operating bandwidth is enlarged by using multi-mode dipoles. A stub-loaded dipole generating two resonant modes (i.e., lower dual-mode dipole) is allocated on the underside of a simple dipole (i.e., upper singlemode dipole) introducing the third resonant mode. When the two sub-antennas are combined together, a three modes performance is achieved. The evolution process of antenna is described and corresponding performances are given. Meandering multi-mode dipole and double concave parabolic reflector are employed to reduce the antenna size and enlarge the operating bandwidth. A demonstration wideband antenna is designed, fabricated and measured. Experimental and simulated results show good agreement, and the proposed planer printed quasi-Yagi antenna presents an excellent end-fire radiation and high radiation efficiency.