Electronics-Based Free-Space Terahertz Measurement Using Hemispherical Lens Antennas

Nonchanutt Chudpooti,Prayoot Akkaraekthalin,Nutapong Somjit,Ian D Robertson,Natapong Duangrit

doi:10.1109/access.2019.2929697

Abstract

This paper introduces a novel free-space terahertz (THz) characterization setup featuring an electronic-based technique and miniature additive-manufactured hemispherical lens antennas. By using in-house custom-made hemispherical lenses, radiation characteristics of the electromagnetic (EM) wave of the measurement setup, e.g. the radiation pattern as well as the collimated and focused beam size of the THz beam, can be precisely predicted and synthesized by appropriately selecting the radius size of the lenses. This technique eases design and measurement setup complexity as compared to the existing conventional THz measurement setups without compromizing the measurement accuracy and reliability. To demonstrate the THz measurement setup developed in this paper, an asymptotically single-mode hollow Bragg fiber operating from 0.246 to 0.276 THz was characterized for its EM transmission properties. The measurement results characterized by this setup are in good agreements with the results obtained from the analytical study and a conventional free-space THz measurement system. The novel THz measurement technique was also characterized for its critical properties, e.g. reliability, repeatability, sensitivity, and accuracy, indicating that the setup can achieve highly accurate measurement quality while still offers various advantages compared to all other existing THz measurement setups such as ease of measurement that allows non-THz expert to setup, setup flexibility, cost-effectiveness, smaller required measurement space, less sensitivity to measurement environments, etc.

Highlights

Terahertz (THz) technology has become very attractive for many engineering and scientific applications, e.g. material characterization [1]–[7], high-resolution imaging [8]–[15], and medical technologies [16]–[18], due to many various advantages over other technologies [19]–[22]
This paper presents a novel free-space electronicbased THz measurement setup featuring custom-made photopolymer-based hemispherical lens antennas fabricated by digital-light manufacturing process
CONVENSIONAL FREE-SPACE MEASUREMENT SYSTEM Fig. 1 shows working principles of three different free-space electronic-based THz measurement setups, comparing the conventional and nonconventional characterization systems with various tools and components required for measurements and directions of THz collimated beams used to measure a DUT and the measurement technique developed in this work

Summary

Introduction

Terahertz (THz) technology has become very attractive for many engineering and scientific applications, e.g. material characterization [1]–[7], high-resolution imaging [8]–[15], and medical technologies [16]–[18], due to many various advantages over other technologies [19]–[22]. CONVENSIONAL FREE-SPACE MEASUREMENT SYSTEM Fig. 1 shows working principles of three different free-space electronic-based THz measurement setups, comparing the conventional and nonconventional characterization systems with various tools and components required for measurements and directions of THz collimated beams used to measure a DUT and the measurement technique developed in this work.

Results

Conclusion