Cost-Effective Technology Development

Camera systems are in widespread use as sensors that provide information about the surrounding environment. But this can struggle with image interpretation in complex scenarios. In contrast, mmWave radar technology offers a more straightforward view of the geometry and motion of objects, making it valuable for applications like autonomous vehicles, where radar aids in mapping surroundings and detecting obstacles. Radar’s ability to provide direct 3D location data and motion detection through Doppler effects is advantageous, though traditionally expensive and bulky. Advances in SiGe device integration are producing more compact and cost-effective radar solutions. Plextek aims to develop mm-wave radar prototypes that balance cost, size, weight, power, and real-time data processing for diverse applications, including autonomous vehicles, human-computer interfaces, transport systems, and building security.

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 technical paper by Dr. Rabbani and his team presents research on metamaterial-based, high-gain, flat-panel antennas for Ku-band satellite communications. The study focuses on leveraging the unique electromagnetic properties of metamaterials to enhance the performance of flat-panel antenna designs, aiming for compact structures with high gain and efficiency. The research outlines the design methodology involving multi-layer metasurfaces and leaky-wave antennas to achieve a compact antenna system with a realised gain greater than +20 dBi and an operational bandwidth of 200 MHz. Simulations results confirm the antenna's high efficiency and performance within the specified Ku-band frequency range. Significant findings include the antenna's potential for application in low-cost satellite communication systems and its capabilities for THz spectrum operations through design modifications. The paper provides a detailed technical roadmap of the design process, supported by diagrams, simulation results, and references to prior work in the field. This paper contributes to the advancement of antenna technology and metamaterial applications in satellite communications, offering valuable insights for researchers and professionals in telecommunications.

This technical paper highlights the ambiguity in the antenna technical literature regarding the radiation resistance of folded antennas, such as the half-wave folded dipole (or quarter-wave folded monopole), electrically small self-resonant folded antennas and multiple-tuned antennas. The feed-point impedance of a folded antenna is increased over that of a single-element antenna but does this increase equate to an increase in the antenna’s radiation resistance or does the radiation resistance remain effectively the same and the increase in feed-point impedance is due to transformer action? Through theoretical analysis and numerical simulations, this study shows that the radiation resistance of a folded antenna is effectively the same as its single-element counterpart. This technical paper serves as an important point of clarification in the field of folded antennas. It also showcases Plextek's expertise in antenna theory and technologies. Practitioners in the antenna design field will find valuable information in this paper, contributing to a deeper understanding of folded antennas.

This paper describes the design and characterization of a frequency-scanning meanderline antenna for operation at 60 GHz. The design incorporates SIW techniques and slot radiating elements. The amplitude profile across the antenna aperture has been weighted to reduce sidelobe levels, which makes the design attractive for radar applications. Measured performance agrees with simulations, and the achieved beam profile and sidelobe levels are better than previously documented frequency-scanning designs at V and W bands.

The design of a 16-element waveguide array employing radiating T-junctions that operates in the Ku band is described. Amplitude weighting results in low elevation sidelobe levels, while impedance matching provides a satisfactory VSWR, that are both achieved over a wide bandwidth (15.7-17.2 GHz). Simulation and measurement results, that agree very well, are presented. The design forms part of a 16 x 40 element waveguide array that achieves high gain and narrow beamwidths for use in an electronic-scanning radar system.

This paper presents a sensor for measuring auditory brainstem responses to help diagnose hearing problems away from specialist clinical settings using non-invasive electrodes and commercially available headphones. The challenge of reliably measuring low level electronic signals in the presence of significant noise is addressed via a precision analog processing circuit which includes a novel impedance measurement approach to verify good electrode contact. Results are presented showing that the new sensor was able to reliably sense auditory brainstem responses using noninvasive electrodes, even at lower stimuli levels.

Passive retro-reflectors that modulate a scattered RF signal but do not transmit in their own right are well known. They are widely used in RFID tags, and keyless entry systems with a number of standardised solutions defined within the industry. The main advantage of these systems is that the mobile unit (the tag) can either avoid completely the use of a battery by powering itself from the incident RF ‘interrogating’ signal or only require a very small battery with a long life. This enables a ‘disposable’ tag to be engineered at very low cost, size and weight. However, there are many potential applications that require a somewhat longer transmission range than can sensibly be achieved with this method. The conventional paradigm requires a higher power ‘interrogating’ signal in order to increase range and there are obvious limits to how far this can be taken. The combination of regulatory restrictions and the steep range vs power slope that results from the fundamental mode of operation generally restrict the range to a few metres at most. Plextek have been taking a fresh look at the possible ways of circumventing this obstacle to produce a long range device that is nevertheless RF passive (does not transmit but only scatters). This paper describes in outline some ideas in this space, some initial experiments that have been done and some potential applications of the techniques.

An automated sensor system that determines whether rooms within a building are occupied by a person or people has many applications. These divide broadly into the following classes: Security: Whole-site surveillance from control node, cases where a room should not be occupied, intruder detection and asset tracking. Safety: Identification of lone workers during non-core hours and remote supervision of isolated working environments. Confirmation of building evacuation. Management of high risk processes. Facilities Management: Environmental controls (lighting/heating) to meeting room booking aid. Sensors that seem to solve this problem are plentiful and it is only when they are considered in detail that their deficiencies become apparent. This short paper makes this case and introduces a new type of sensor based on an optical method.

Yocto is a comprehensive project designed to address the complexity of building custom Linux distributions for embedded systems. Unlike conventional Linux distributions (distros) created for standard PC architectures, Yocto caters to the diverse and often incompatible hardware in the embedded world. By providing a sophisticated build system based on layered scripts called "recipes," Yocto streamlines the process of creating, maintaining, and updating embedded distros. Each package within a distro has its own recipe, maintained by the package developers, ensuring that updates and customizations are manageable and consistent. This structure allows developers to define precise sets of packages for their embedded systems, facilitates updates through package managers, and supports a wide range of hardware platforms. With support from major chip and board manufacturers, Yocto is becoming the go-to toolset for embedded Linux development, offering unparalleled flexibility and control for developers aiming to create finely tuned, market-ready products.