The use of radar to monitor human vital signs has long been studied. Radar sensing technology enables continuous and contactless monitoring of heart rate and respiration rate while featuring low power consumption and a small PCB footprint. By embedding innovative 60-GHz radar sensors into a wide variety of home consumer electronics, from computers to televisions, we are making contactless vital sign sensing and health monitoring a reality.
Many diseases can be detected early based on irregularities in cardiopulmonary data. As technology advances, various new means of discovery are emerging. Combining consumer electronics with digital health monitoring has grown in popularity since smartwatches were first introduced. This positive trend is also evident in the healthcare industry, where Figure 1 shows that industry investment in digital health has grown 20-fold over the past 10 years, with the most recent period of growth being extremely dramatic.
The most important vital signs that can be monitored include heartbeat and respiratory rate. This information can be used for early detection of conditions such as cardiovascular disease or chronic obstructive pulmonary disease (COPD). Similarly, the detection of diseases such as sleep apnea can also be achieved through sleep monitoring.
The health tracking and monitoring of most of the technologies currently used need to be realized through direct contact between electrodes or sensors and the patient’s skin. This type of contact monitoring is used in both high-precision medical systems used in hospitals and wearable devices in the consumer industry.
But none of these solutions can do without cables that interfere with the patient’s freedom of movement, or the hassle of regular recharging. In addition, these methods are not suitable for people with skin allergies or skin injuries. Again, these contact-dependent measurements are often difficult for infants and the elderly.
Therefore, in the digital healthcare market, there is a need for a product that enables contactless and continuous user monitoring.
Advantages of Radar
The radar sensor enables continuous and contactless monitoring of heartbeat and respiratory rate. It also supports long-term logging of important data, and users don’t have to keep thinking about monitoring it. This not only helps doctors to make an accurate diagnosis, but also ensures the hygiene of patients. Therefore, the important sensing capability of radar is expected to solve many challenges in the healthcare industry today.
But how does life sensing work with radar technology?
The radar transceiver transmits a low-energy RF signal through its Tx antenna, and then receives the reflected signal through the Rx antenna. Typically, moving targets cause a Doppler shift, which can be measured by comparing the received signal with the transmitted signal.
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Small chest movements caused by breathing and heartbeat can be detected with high-sensitivity sensors like the Infineon XENSIV™ 60-GHz radar sensor. Thanks to advanced algorithms, heartbeat and breathing rates can be accurately extracted from the signal. This may also satisfy the requirements for medical certification.
In the context of life sensing, radar technology has four major advantages over previous technologies: imperceptible, robust, energy-efficient, and compact size.
- Imperceptible
For vital sign sensing, radar technology has the advantage of having little to no impact on the patient. The only requirement is that the user is within range of the device, usually within 1.5 meters. It would be nice if the user’s chest could face the sensor, but it’s not mandatory.
Since radar can detect through non-conductive materials, people can wear any type of clothing or cover their body with a thin blanket. This capability also allows radar equipment engineers almost freedom of choice in housing materials and shapes to suit consumer application requirements.
Also read: About PCB materials – selection and performance
- Robust
Furthermore, the function of the radar sensor is hardly affected by the surrounding conditions. For example, it works continuously and reliably whether the room is completely dark or very bright, or dusty, foggy or humid. Therefore, the radar sensor does not interfere with people’s daily life. Thanks to advanced signal processing, the sensor can also distinguish between human and non-human targets, so small pets and other sources of clutter can be ignored.
- Energy-saving
With low power consumption of only a few milliwatts, the radar can be used 24/7. In addition, typical radiated power is about 10dBm (10mw), or even less. The radiated power from the radar sensor is very low and has no adverse effects on the human body. If you want to find a reference, just look at smartphones. The radiation power of 5G mobile phones is also as high as 20dBm (100mw). Before 5G, mobile phone radiation was much greater.
Also read: 5G vs 4G – what is the difference
- Compact size
The size of the radar chip is also very compact. The Infineon BGT60UTR11AIP (see Figure 3) measures 4.05 x 4.05mm and is the smallest 60GHz radar sensor with integrated antenna on the market. Sensors like this can be easily integrated into consumer electronics, where they can provide many enhanced functions. Integrated application products include smart hubs, laptops, tablets, smart TVs and many other smart home devices.
Also read: Understanding the PCB Antenna : A Comprehensive Guide
Bringing Health Monitoring to the Smart Home
The lessons of the epidemic have prompted people to realize the importance of knowing their health status and preventing potential diseases. Likewise, advances in machine learning are enabling the maximum use of the capabilities of sensor technology. As a result, radar technology will increasingly find its way into smart homes for health monitoring.
Continuous recording of vital data means it can be easily shared with doctors for accurate diagnosis. Thanks to artificial intelligence, the analysis of recorded data and trends over time can lead to early detection of diseases, such as symptoms of known or suspected diseases such as sleep apnea can be identified, recorded, and shared with doctors. In addition, in the event of apnea or risk of apnea, the device can automatically and timely send a distress alert to the medical emergency system.
In fact, it’s not just sleeping people that can be monitored by radar. Due to the small size of the radar chip, the radar sensor can be directly integrated into almost all types of smart home devices, including smart TVs, laptops or lamps. This enables the sensor to monitor a person’s heartbeat and breathing rate with the help of smart lights, whether he/she is sleeping, watching TV, or working or reading in front of a laptop.
Radar technology can also detect a heart attack immediately and trigger an appropriate emergency call. When integrated into a motor vehicle, it can also instruct driver assistance systems to bring the car to a safe stop. In addition, radar sensors can also be used to detect signs of fatigue and remind people to take proper breaks during work or driving.
At the same time, radar sensors can perform other functions besides pulse and respiration monitoring (see Figure 4). For example, they can be used for fall detection, and there is ongoing research using radar for blood pressure measurement.
Because radar technology is capable of simultaneously detecting micromotion, velocity, and direction, products equipped with radar can use this information to support more complex applications beyond life sensing. Radar sensors can also be used for robust human detection, for example, to automatically switch the device into an energy-saving mode when no one is sitting in front of a TV or laptop. Gesture control is also possible, as well as tracking the positions of multiple people in the room.
How Does Radar Sensor Work?
With its XENSIV™ 60-GHz radar sensors such as the BGT60UTR11AIP or BGT60TR13C, Infineon provides developers with everything they need to incorporate life-sensing into their designs. Infineon has many years of experience in the automotive and industrial radar markets and is one of the pioneers in the use of radar for life sensing in consumer electronics.
Because it can provide strong support for the software and hardware design and testing of customers’ products, it in turn strengthens the company’s high-quality and high-reliability product series. All in all, product engineers save development time and can deliver high-quality final products.
Several customers and partners have successfully integrated Infineon radar sensors in their life sensing products. For example, the Swiss company Sleepiz offers a medically certified sleep monitoring device (see Figure 5); in addition, Google’s Nest Hub 2 is also using Infineon’s radar sensor as an additional function of its products to detect vital signs during sleep disorders.
Conclusion
With radar technology in place, it is possible to build consumer-facing products that take smart devices to a whole new level and bring smart healthcare to the mass market. Radar monitoring is the only non-contact technology that can continuously and anonymously monitor heart and breathing rates.
Radar sensors provide vital sensing for the consumer electronics and healthcare markets. From monitoring premature babies to early disease detection to monitoring the health and medical conditions of the elderly, radar enables low-power and accurate vital sensing at any stage of life.
