Scientists at the University of Sydney have developed a new type of photonic radar system and sensors that promise noninvasive medical monitoring.
As engineering advances such as self-driving cars, home automation, and smart city design become more common in everyday life, engineers have a lot of work to do. Some of the tasks involve developing better and more efficient imaging techniques for high-resolution and real-time sensing for a given environment.
Developing such technologies relies on innovation in new areas and reimagining current and old technologies.
Block diagram of a universal radar system
One of these inventions, called photon radar, improves traditional radar technology while potentially integrating into existing systems and opens the door to new and potentially life-saving applications.
This article will highlight some of the shortcomings of traditional radar in modern implementations, as well as a new photonic radar technology currently under development at the University of Sydney.
Traditional radar imaging techniques
Radar or radio detection and ranging are some of the most widely used methods for detecting and tracking objects and analyzing their velocity and angular momentum.
These systems have existed since the 1940s. At first, their use was closely related to military operations during World War II.
Since then, radar has found other uses in our daily lives as sensing tools for different types of devices and technologies. This adoption is due to the fact that radar principles are generally very simple and easy to operate and manufacture.
Radar works by sending short pulses of electromagnetic waves from transceivers and calculating the time it takes for them to bounce off. Thus, it can measure any object that hinders the system and its distance and position relative to the measuring instrument.
Still, there are some drawbacks in the implementation of traditional radar technology in modern applications. Typically, radar systems are developed on a case-by-case basis, making a single system proprietary based on a small range of specific sensing needs.
While some companies are working on standardization of radar development, individual applications often require very different electronics, different operating frequencies, and different power requirements, even if their development and software platforms are generic.
Despite the progress of typical radar systems, there are still areas for improvement. A radar system designed to provide more accurate and precise radar uses photonics.
Photon radar has a higher image quality (resolution) and can detect millimeter levels.
Photonic radar technology at the University of Sydney
One of the latest advances in photon radar technology is a device developed by the University of Sydney called "Advanced Photon Radar".
Led by Professor Benjamin Eggleton and with the support of the U.S. Air Force and the Australian Research Council, the team behind the project set out to improve the radar and build ultra-high-resolution imaging sensors.
Similar to conventional radar, the system uses radio waves to measure the velocity, position, and angular velocity of objects; however, some of its main components are made using photonic circuits rather than electronic circuits.
This use of photonics gives it an advantage over conventional radar, and the imaging resolution is millimeters rather than meters.
In addition, photonics reduces the hardware burden on radar systems while improving their sampling accuracy and allowing the use of a wider range of operating frequencies without any additional components.
Schematic diagram of the experimental apparatus demonstrated by the researchers on radar ranging
Reducing the hardware burden, or in this case, essentially using fewer components to do more, will make photonic radar systems have a universal use, be energy and space efficient, and be less costly than traditional radar systems.
This particular device consists of the following parts:
- Photon signal generator that generates ultra-wideband photon signals
- A photoelectric converter that converts these signals from photons to microwaves
- RF antenna
- A photon signal mixing unit that demodulates a signal in the optical domain
- Electro-optical converters for signal processing
Applications of photon radar systems
There are no limits to the potential applications of photon radar systems; however, Professor Eggleton and collaborator Ziqian Zhang are currently working on future life-saving applications in the field of medical surveillance.
Zhang Ziqian (left) and Professor Benjamin Eggleton (right) demonstrate their radar system. Image courtesy of the University of Sydney
Using their photon radar sensors, the team hopes to develop a new way to detect patients' vital signs, such as breathing and heart rate.
By continuously measuring the subtle movements of a patient's body, the technique can detect their breathing patterns and identify potential abnormalities without having to connect any device to the patient itself. This approach will facilitate non-invasive measurements of burn patients or infants that would otherwise be sensitive to traditional sensors and monitoring devices.
Similar measurements can be done using video capture technology that carries more data and the user can use to identify the patient's private information.
Photon radar systems can help solve the privacy problems of medical monitoring because it can only capture specific information related to patient health, allowing for complete privacy and anonymity, while also complying with laws and regulations in the field.
The future of photon radar systems
The photon radar system is still under development and researchers at the University of Sydney are planning multiple testing phases after ethical approval.
Their current plan is to test the technology first on the toad and then transfer it to human participants.
Due to the non-invasive nature of the radio waves used in radar, vital signs medical devices based on this technology are completely safe for widespread use in home or hospital settings.
In the future, the team plans to shrink these sensors to be small enough to be embedded in phones and other devices.