Broadband THz Corrugated Bull’s Eye Antennas

Despoina Kampouridou,Alexandros Feresidis

doi:10.1109/access.2021.3099879

Despoina Kampouridou, Alexandros Feresidis

Open Access

https://doi.org/10.1109/access.2021.3099879

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Abstract

A 3-dB gain and input impedance bandwidth enhancement technique for THz periodically corrugated metallic antennas, also known as Bull's Eye antennas, is presented. A novel design that exploits the depth qualities of the corrugations is introduced, by employing two different depth values for two sets of indented rings. While the gain bandwidth of most single-depth planar corrugated antennas is limited, the 3-dB gain bandwidth of the proposed dual-depth design is expanded along with a high maximum gain. The simulated optimum model of 10 rings at around 300 GHz exhibits a 3-dB gain bandwidth of 8.85% with a maximum gain at broadside of 21.3 dBi. A leaky-wave analysis has been performed via a simple transcendental equation at the level of the gap openings in order to explain the antenna principle of operation. A prototype of the optimum antenna design has been fabricated and measured. The typical subwavelength slot feeding of Bull's eye corrugated antennas is substituted with an easy-to-fabricate open waveguide aperture, yielding a broadband matching performance. Measured results demonstrate a good agreement with simulations and validate the proposed antenna design.

Highlights

The terahertz spectrum is a highly developing frequency band, suitable for a variety of applications including imaging, ultra-high-speed wireless telecommunications and sensing, envisaged to achieve data rates of 100 Gbps or higher
Modern antennas usually require high gain, compact size and a broadband gain/directivity performance in order to meet the demands of these THz systems
Corrugated metallic structures operating at millimeter wave and sub-millimeter wave frequencies have attracted

Summary

INTRODUCTION

The terahertz spectrum is a highly developing frequency band, suitable for a variety of applications including imaging, ultra-high-speed wireless telecommunications and sensing, envisaged to achieve data rates of 100 Gbps or higher. In addition to the necessity of a broadband gain performance of the antenna, a satisfactory input matching response is desired (typically below −10 dB over a large S11 bandwidth), especially in applications where dielectric or other packaging materials are superimposed on the antenna and can potentially affect their radiation Another significant challenge at the low-THz band is the fabrication complexity and costs that emerge due to the small dimensions of devices and the current limitations of the available fabrication techniques and tools. This effect has been exploited for only a few applications so far [12] These antennas are typically excited by a waveguide-fed resonant slot aperture, which offers high gain performance but limits the matching bandwidth as a trade-off.

THE DUAL-DEPTH CONCEPT

FABRICATION AND MEASUREMENTS

CONCLUSION