Terahertz Technology for Future Road Vehicles

Lead Research Organisation: University of Birmingham
Department Name: Electronic, Electrical and Computer Eng


This programme will lay the scientific foundations for a new generation of sensor systems that will be mounted in vehicles to enhance the safety and efficiency. The sensors, small enough to be mounted unobtrusively on vehicles, will allow high resolution images to be produced in real time, that can be read and interpreted by intelligent vehicle systems to determine appropriate actions in hazardous circumstances and to dynamically control the vehicle to reduce fuel consumption. Sharing the images, or the information obtained from them, with the infrastructure and with other vehicles, will also make it possible to enhance safety and efficiency collectively within whole cohorts of vehicles. Sensors based on this technology will impact on future integrated automotive transport systems, supporting an intelligent transport philosophy with efficient use of renewable energy sources, low carbon emissions and enhanced safety for all road users.

The new sensors will exploit the technology of circuits and devices in the 0.3 THz to 1 THz frequency range. Although this range, falling in between the upper end of the radio spectrum and the lower end of the infra-red, is currently not widely used, the device and circuit technology will mature over the next decade. There are several potential advantages in the use of this frequency band, as opposed to the lower frequency microwave and mm-wave bands or the infra-red and optical bands. The antennas required in the low THz band are smaller than those in the microwave and mm-wave bands, in proportion to the wavelength. The image resolution achievable is improved. There are two reasons for this. Firstly, narrower beams can be produced while using reasonably small antennas, when the wavelength is so short (less than 1 mm). Secondly, the high bandwidths available when using such high frequencies make it possible to distinguish between more closely spaced features in the reflected signal. At the same time, waves in this band are not susceptible to complete obscuration by road dirt or precipitation, as infra-red and optical systems would be.

Before and during this work, there will be a strong focus on vehicle system applications, with input from automotive industry experts, to identify the specific requirements of future vehicle systems.

To generate the required images, low THz waves must be transmitted from the vehicle, propagate through the surrounding environment and be scattered from objects and surfaces. Scattered waves propagating back to the vehicle and received by the sensor antenna provide the information required to form an image. The main research work activities in this project all relate to these physical aspects of the imaging systems. Firstly, the properties of the road environment will be determined to find the specific frequency windows in which low THz signals can propagate through air, precipitation, vehicle exhaust gases, road spray and airborne particles such as dirt and grit. This will involve a combination of measurements in controlled, enclosed artificial environments created in the laboratory, and real road trials. Then, the scattering properties of typical road scenes and surfaces will be analysed to determine the most appropriate frequencies and waveforms to use for imaging.

A major part of the research will involve the study of the antennas and beamforming networks that will be required to implement low THz imaging systems on vehicles. Working at the boundary between the radio frequency spectrum and the optical spectrum provides opportunities to exploit and merge transmitter concepts based on both lenses and antennas. The system requirements will be studied to arrive at recommendations for transmitter and receiver architectures that could be realised using the emerging circuit and device technologies.

Planned Impact

Ultimately the beneficiaries of this research will be all road users. The high resolution imaging systems made possible by the sensors which form the subject of this research will be deployed in road vehicles to enhance safety, for road users both inside and outside of the vehicle, and to improve the efficiency of vehicles, thereby reducing the effect of road traffic on the environment. These impacts will begin when the first systems come to market, probably in luxury vehicles initially, within about 5 years of the end of the project, and will grow as the technology penetrates into the mass market for vehicles, over about a 10 year period.

Vehicle manufacturers within the UK such as Jaguar LandRover will benefit from the opportunity to maintain their advantages in the commercial automotive market, by being amongst the first in the world to market these advanced systems.

Imaging systems based on low THz technology will also be of interest to manufacturers of military systems and unmanned vehicles, such as BAE Systems and Thales.

The work will benefit UK and EU policy makers who have a strategy to reduce dependance on the USA in this strategic technology area. Transport system researchers and policy makers would benefit from early indications of the capabilities of these imaging systems and their potential impact on future road infrastuctures for intelligent transport systems.

Researchers in THz active and passive component technologies will benefit from the research outcomes. The work described here will provide a pathway to what could be the first mass market application for low THz technology. As such, during this programme, the research will provide benchmarks for the assessment of the performance of such device technologies, in terms of basic link budget parameters such as transmitter power and phase noise, and receiver noise figures. Beyond the completion of this programme, the research will lead to a mass market application for such devices. Automotive systems typically have a very long gestation period, because of the need to establish safe, reliable operation subject to international standards, along with minimum manufacturing costs in high volume. Therefore a 10 year timescale might be expected for the development of this mass market. Existing UK companies and new spin-out companies specialising in the design and manufacture of mm-wave and THz circuit modules would benefit from the growth of this new market.

The researchers working on this project will gain valuable technical and professional experience from working in this important and rapidly developing area of technology, which could provide a springboard for longer term research and/or academic careers. The reputational benefit of the work will provide the investigators with opportunities to continue recruiting and training doctoral and masters level students. Masters level teaching informed by the outcomes of the research will further strengthen the University's reputation in this area.
Description We have characterised the attenuation of low THz electromagnetic waves by a range of different obscurants occurring in representative road environments, both as contaminants on the radome and as airborne particulates. Measurements have been performed at 150, 300 and 670 GHz. Radome contaminants studied include: water of varying salinity levels, water with typical levels of road dirt, as droplets and as a continuous film; sand layers with varying depth and moisture content; ice; road fuels (diesel and gasoline); and fresh and dried leaves. The effect of obscurants on signal reduction has been characterised by measuring the ratio of reflected signals from a reference target through the radome, with contaminant and without contaminant present. Measurements have been compared to theoretical models, demonstrating good agreement. The water results show strong signal reduction due to the presence of a uniform thickness of water and higher signal reduction with increasing frequency. However, the loss through more realistic distributed water droplets is lower with shorter wavelength. The results suggest that ice, diesel, gasoline and dry leaves are almost transparent and will not significantly degrade sensor performance at 150, 300 GHz and 670 GHz. The main loss mechanism arises from water, for example bound in fresh leaves or wet sand. By comparing with losses at 77 GHz where current commercial automotive radar systems operate, we conclude that realistic radome contaminants are unlikely to be a barrier to the implementation of THz radars for the applications envisaged in this project.
Measurements of attenuation through falling rain at 300 GHz show specific attenuation figures that are low enough to allow a THz automotive radar with about 100m range to operate in heavy rain, up to 10 mm/hour. Similarly, our measurements of attenuation through wet and dry falling snow at 300 GHz show attenuation monotonically increasing with snowfall rate. Higher attenuation occurs for snow with higher water content. In both cases the spread of the measured results indicates the need for developing a detailed model of the joint distribution of raindrop and snowflake size, shape and inhomogeneity, but the attenuation levels are low enough to make short range (100 m) automotive radar operation realistic.
We have made very detailed measurements of low THz attenuation through falling rain, while simultaneosly measuring the size, velocity and distribution of rain drops. This provides entirely new and valuable information on the extremes of rain attenuation that will affect the range of weather conditions (rainfall rates and types) in which THz imaging systems can be used reliably, and what transmitted power levels will be necessary to achieve this.
We have designed and commissioned a radar system capable of carrying out similar measurements at 670 GHz, and we have initial results (some submitted for publication) on transmissivity through car bumper material, headlamp covers and uniform water layers.
A dielectric extended hemispherical lens antenna designed to produce highly directive beams at low THz frequencies and suitable for automotive radar has been designed, built and successfully tested. The antenna is fed by a standard WR-3 rectangular waveguide fitted at the bottom of the lens incorporating an optimized matching structure. Further design and development of this design has been carried out to enable this design to be adapted for a steerable fan beam as required for automotive radar. Further work is necessary to complete a practical hardware demonstration of this antenna.
Exploitation Route We expect the attenuation measurements and the antenna design to be of use to designers of future imaging radar systems, both for automotive radar for autonomous vehicles, and for other autonomous robotic platforms. We are continuing to develop our antenna design concepts through PhD project and other research programmes to replace the current spot beam with a fan shaped beam which will be advantageous for use in an automotive radar system.
The concepts developed in this project have contributed already to several higher TRL projects in which mm-wave and low THz radar imaging systems are integral to the development of autonomous vehicles.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics,Transport

Description The underpinning science behind THz radar scattering has led to several further research projects and higher TRL work, and have contributed to an impact case study being submitted by UoB for REF 2021 in UoA12.
First Year Of Impact 2018
Sector Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Transport
Impact Types Economic

Description CORTEX
Amount £3,400,000 (GBP)
Organisation Jaguar Land Rover Automotive PLC 
Department Jaguar Land Rover
Sector Private
Country United Kingdom
Start 03/2019 
End 08/2021
Description COSMOS
Amount £1,672,176 (GBP)
Funding ID 104526 
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 01/2019 
End 03/2021
Description EPSRC Strategic Equipment Fund: 10 MHz to 1.1 THz Vector Network Analyser
Amount £1,143,093 (GBP)
Funding ID EP/P020615/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 08/2017 
End 08/2019
Description Industrial CASE Account - University of Birmingham 2015
Amount £412,353 (GBP)
Funding ID EP/N509073/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 08/2015 
End 09/2020
Description Millimeter-wave Antennas and Components for Future Mobile Broadband Networks (MILLIBAN)
Amount £743,439 (GBP)
Funding ID EP/P008380/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2017 
End 04/2020
Description Sub-THz Radar sensing of the Environment for future Autonomous Marine platforms - STREAM
Amount £854,174 (GBP)
Funding ID EP/S033238/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2019 
End 12/2022
Description TASCC: Pervasive low-TeraHz and Video Sensing for Car Autonomy and Driver Assistance (PATH CAD)
Amount £1,677,753 (GBP)
Funding ID EP/N012372/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 12/2015 
End 11/2019
Description European Microwave Conference Workshop on THz Electronics for Communication and Remote Sensing Systems 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Workshops on THz Electronics for Communication and Remote Sensing were held during European Microwave week in 2017 and 2018, organised and chaired by the PI of TRAVEL. These provided a valuable professional forum for dissemination of results from TRAVEL, on the research work on propagation, novel THz antenna designs and radar imaging. It was also a platform for other, mainly UK based researchers undertaking related work in THz technology, and it proved to be a valuable opportunity for discussing future possible research collaborations.
Year(s) Of Engagement Activity 2017,2018
URL https://www.eumweek.com/archive/eumweek2018/www.eumweek.com/conferences/workshop_schedule.html