High-gain bow-tie antenna using array of two-sided planar metamaterial loading for H -band applications

Abstract

A method to significantly increase the gain of a bow-tie antenna based on metamaterial concept is presented. The μ-negative feature of the proposed two-sided planar metamaterial (TSPM) structure is investigated by retrieving its constitutive parameters from the S-parameters. The proposed structure consists of six slabs that are loaded with a 3 × 3 array of TSPM unit cells, which are embedded in azimuth plane of a modified bow-tie antenna vertically. The TSPM unit cells provide a medium of low effective permeability. The dimensions of the slabs are 30.6 × 20.6 mm2 at 7 GHz. To show the adaptability of the proposed high-gain antenna, the structure was designed to cover H-band applications (6-8 GHz). Consequently, a small antenna is designed in comparison with initial bow-tie structures. The corresponding return loss of the antenna is better than 10 dB over 6 to 8 GHz. The proposed metamaterial antenna was manufactured and its characteristics measured to verify the proposed idea. Good agreement between the measured and simulated data is obtained. Maximum gain measured of the antenna is 10.21 dB at 7.5 GHz, constituting a maximum gain enhancement of 7 dB for H-band in comparison with a bow-tie antenna without any metamaterial structures.