Gain enhancement of bow‐tie antenna using fractal wideband artificial magnetic conductor ground

Abstract

A novel fractal wideband artificial magnetic conductor (AMC) structure is designed as the ground plane of a printed bow‐tie antenna for gain enhancement and low profile. The origin printed bow‐tie antenna is operated in the range from 1.67 to 2.06 GHz for a VSWR <2. The AMC structure consists of 6 × 9 first‐order fractal unit cells that are made up of four circles and four smaller circles, and the ±90° reflection phase band is 1.1–3.03 GHz. Both the AMC ground plane and bow‐tie antenna are fabricated and measured. The distance between the antenna and the AMC is reduced to one‐eighth of the wavelength in free space at 1.7 GHz. The experimental results show that the composite antenna has a wide bandwidth from 1.64 to 1.94 GHz, with a relative frequency bandwidth of 16.7%.