Plextek (United Kingdom)

Abstract The recent article by Suganya et al. is incomplete and, in some places, unclear, which has resulted in misleading and incorrect conclusions on the performance of their bent wire dipole antenna. These comments serve to address the shortcomings of their paper.

Internet of things is projected to make its way into all spheres of human life in the near future. This has been compounded with the growing demand for contactless solutions in the wake of the recent pandemic. A potential solution could involve a privacy-preserving gesture-based control system that could control a wide range of appliances. Implementing such gesture-based control systems is mainly conducted using opaque box Artificial Intelligence (AI) models. Systems based on such opaque box AI models have shown high-performance metrics on in-distribution data in a lab environment. However, they are prone to failure when exposed to real-world out-of-distribution data where they cannot be tuned or calibrated due to their complexity and opaqueness. Interval Type-2 Fuzzy Logic-based explainable AI models offer an alternative to opaque box models showing comparable performance on lab in-distribution data. In contrast, in the real world, out-of-distribution data, the type-2 fuzzy models could be easily calibrated and tuned (thanks for their explainability) to provide similar performance to those achieved on the lab in-distribution data.

A novel construction technique to realize ultralight and flexible log-periodic dipole array antennas for weight-sensitive applications is described. Simulated and measured s11 and 3D radiation patterns for a design covering 1-6 GHz and weighing only ~13 g show good agreement.

This paper presents a range of novel low-cost millimeter-wave radio-frequency sensors that have been developed using the latest advances in commercially available electronic chip-sets. The recent emergence of low-cost, single chip silicon-germanium transceiver modules combined with license exempt usage bands is creating a new area in which sensors can be developed. Three example systems using this technology are discussed, including: gas spectroscopy at stand-off distances, non-invasive dielectric material characterization and high performance micro radar.

This paper presents an initial empirical path-loss propagation model for communication links operating at streetlight/ roof-top heights over the ranges of 100 m to 10 km in urban and suburban environments. The statistical path-loss model presented uses data taken from a significant number of deployed street-light telemetry systems transmitting in the licence exempt/ ISM bands at 868 and 915 MHz. This propagation model provides a valuable tool for network planning where typical cellular propagation models might not be appropriate.

This paper describes the application of the well-known Gilbert-cell mixer technique at mm-wave frequencies. A pseudomorphic HEMT monolithic design is described, in conjunction with a bondwire compensation technique, to produce low conversion loss (<4 dB) with low LO power at frequencies beyond 40 GHz.