A Study on Gain Enhanced Leaf-Shaped Bow-Tie Slot Array Antenna within Quasi-Millimeter Wave Band

Abstract

In this paper, a linear array of 4 leaf-shaped bowtie slot antennas is proposed for use in quasi-millimeter wave band. The slot antennas array is designed to operate at 28 GHz frequency band. The leaf-shaped bowtie slot antenna is a type of self-complementary antenna with low profile and low cost of fabrication. The proposed antenna structure offers improvement in radiation pattern, gain, and -10 dB impedance bandwidth. Through out of this paper radiation pattern, actual gain, and -10 dB impedance bandwidth are evaluated by Finite Different Time Domain (FDTD) simulation. Antenna characteristics are analyzed in the frequency range of 27 GHz to 29 GHz. To improve antenna characteristics such as actual gain and -10 dB impedance bandwidth, a dielectric superstrate layer with relative permittivity of 10.2 is placed on top of ground plane of the slot antennas array. Three antenna structures are introduced and compared. With two layers of dielectric superstrate on top of the antennas ground plane, analysis results show that -10 dB impedance bandwidth occupies the frequency range of 27.17 GHz to 28.39 GHz. Therefore, the operational impedance bandwidth is 1.22 GHz. Maximum actual gain of the slot antennas array with two dielectric superstrate layers is 20.49dBi and —3 dB gain bandwidth occupies the frequency range of 27.02 GHz to 28.57 GHz. To validate the analysis results, prototype of the designed slot antennas array is fabricated. Characteristics of the slot antennas array are measured and compared with the analysis results.