Enhancing Efficiency for Wideband Antennas by Controlling the Parasitic Resonance of the Feed Structure

Abstract

Parallel resonance feed structures can be used to implement wideband impedance characteristics. However, at some frequencies, parasitic resonance is generated in the feed structure. Radiation efficiency nullification occurs at the frequency of the parasitic resonance. This frequency moves with the size of the feed structure. In this paper, two antennas with different parallel resonance feed structures are presented. By simply modifying the feed structure, the frequency of the parasitic resonance is shifted. The impedance bandwidth and the efficiencies of the two antennas confirm that antenna performance is significantly enhanced when a parasitic resonance is moved away from the antenna operating band. This research provides a simple and feasible method for the design of practical high-performance wideband antennas.