170 GHz quasi-optical sub-harmonic mixer with a back-to-back lenses packaging based on HDI.

The paper presents a 170 GHz quasi-optical sub-harmonic mixer with a 3D-printed back-to-back lenses packaging. The quasi-optical mixer is comprised by a pair of antiparallel GaAs Schottky diodes, a patch antenna for receiving local oscillator (LO) pump signal, a symmetric-slit patch antenna for receiving radio frequency (RF) signal, dual 3D-printed lenses and a matching network. The quasi-optical mixer with a pair of antiparallel GaAs Schottky diodes is designed on a multilayer build-up printed circuit board (PCB) utilizing commercially low-cost and high-density interconnect (HDI) technology.

High range resolution wideband terahertz FMCW radar with a large depth of field.

Terahertz frequency modulation continuous wave (THz FMCW) imaging technology has been widely used in non-destructive testing (NDT) applications of non-metallic materials. However, THz FMCW real-aperture radar usually has a narrow bandwidth and small depth of field, thus restricting the application of THz FMCW NDT. In this paper, a wideband THz signal (220-500 GHz) generation method is proposed by time-division multiplexing.

Ultra-wideband signal generation and fusion algorithm for high-resolution terahertz FMCW radar imaging.

The terahertz frequency modulated continuous wave (THz FMCW) imaging has proved to be a novel nondestructive testing (NDT) technology for non-metal materials, and the large bandwidth is usually required to meet high range resolution demands in many applications such as multilayer sample under test (SUT). However, broadband THz hardware is difficult to design. In this paper, an ultra-wideband THz FMCW generation method is proposed, which provides frequency modulation bandwidths of up to 386 GHz by time-division multiplexing.

A Low-Cost Metamaterial Sensor Based on DS-CSRR for Material Characterization Applications.

This paper presents a metamaterial sensor using a double slit complementary square ring resonator (DS-CSRR) that has been utilized for the measurement of dielectric materials, especially coal powder. The design is optimized for best performance of deep notch depth in transmission coefficient (Magnitude of S21). Sensitivity analysis of transmission coefficient with respect to structure dimensions has been carried out.

Adaptive terahertz image super-resolution with adjustable convolutional neural network.

During the real-aperture-scanning imaging process, terahertz (THz) images are often plagued with the problem of low spatial resolution. Therefore, an accommodative super-resolution framework for THz images is proposed. Specifically, the 3D degradation model for the imaging system is firstly proposed by incorporating the focused THz beam distribution, which determines the relationship between the imaging range and the corresponding image restoration level.