A continuous real-time monitoring of plants and insects with miniaturized terahertz (THz) systems are described and experimentally tested. Using such compact THz systems, e.g., water uptake, insect infestation and the behavior of pollinators (i.e., honeybees) and pests can be measured dynamically and non-invasively at virtually any position in the close biotope surrounding them.

This paper presents a 194–214-GHz single-sideband (SSB) Schottky diode-based subharmonic mixer. A vertical transition acts as an IF-LO duplexer and an impedance transformer. A four-element mixer array is demonstrated with minimum SSB conversion loss of 8.1–10.4 dB and sideband rejection ratio better than 30 dBc, which shown useful for THz 3-D integrated phased-array system. 

This article presents an approach to manufacturing and assembling inexpensive, lightweight devices using 3-D-printed waveguides and surface-mount technology (SMT). Specifically, stereolithography (SLA) and a combination of electroless and electroplating processes have been employed to develop cavity filters in the X-and C-bands.

This article reports a 223–276-GHz monostatic frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) chip. The TRX is suitable for building massive multiple-input multiple-output (MIMO) radar arrays in the daisy-chain topology because of its cascadable feature based on the injection-locking feedthrough technique. The TRX chip includes an on-chip antenna coupled with a silicon lens, offering a peak effective isotropic radiated power (EIRP) of 27 dBm at 240 GHz. 

A compact waveguide magic-T (WMT) with four coplanar ports is presented for sub-THz power combinating is described. In the WMT, simple and robust geometries, i.e., trapezoidal irises, cuboid-shaped ridge, and waveguide step, are employed to ease manufacturing difficulties at sub-THz frequencies. A WR-4 band (170-260 GHz) prototype is fabricated and measured, showing an average combination efficiency of 92.2% within 175-255 GHz (37.2%-bandwidth).