Today, more than 20 years after the term ‘Internet of Things (IoT)’ was coined, the world is becoming increasingly connected. To do this, millions of sensors and devices are being used.

Various IoT devices have been used to make life more convenient, reduce costs, and improve the quality of life.

Market demand for smart devices and applications that leverage these devices is growing rapidly as more and more users seek to benefit from the convenience, energy efficiency, and security that smart technology brings.

According to market research from Statista , the global IoT market is expected to reach $1.6 trillion by 2025.

One factor that is enabling this growth is something called “intuitive sensing,” which has recently emerged.

Intuitive sensing allows people to interact with smart devices in more natural and seamless ways than ever before.

Implementing intuitive sensing is based on sensing systems within a naturally connected range.

Intuitive sensing enables innovative cognitive capabilities in IoT applications.

IoT applications will be able to ‘see’, ‘hear’, ‘smell’, and ‘sens’ their surroundings.

This makes possible new things that utilize IoT technology in various fields such as smart home, security, and industry.

■ Introduction of radar sensors

With IoT systems and applications Radar sensors can be used to detect and track one or more objects.

Compared to other radio frequency (RF)-based passive/active wireless sensor systems, radar sensors are active systems, meaning they can send out pulses and receive their echoes.

Radar technology can calculate the target's speed, direction, and range (distance from the radar transmitter/receiver).

Some radar sensors have such high sensitivity that they can even detect extremely subtle movements of people and their presence.

High-sensitivity radar technology offers the following advantages for IoT applications:

- Small size: Radar sensors can be reduced in size when developing IoT systems due to their small component size in the overall IoT system. In addition, this small size helps prevent interference with other components or glare to the user when designing the system.

- Robustness: Radar sensors work well under a variety of environmental or weather conditions. For example, radar sensor operation is basically unaffected by changes in temperature or lighting conditions.

- Product Design Flexibility: The biggest feature of radar sensors is that they can be placed under the product cover, which provides flexibility in the design and implementation of IoT products. Radar uses RF signals at high frequencies (e.g. 24 GHz) and can pass through most materials (e.g. plastic, glass, wood). Therefore, it can obtain accurate measurements of objects behind walls or obstacles.

- Sensitivity: Radar sensors can detect even the slightest movement, such as breathing. It enables interesting IoT use cases such as detecting human presence and detecting biometric indicators like heartbeat.

- Power efficiency: Radar sensors consume relatively little power, which allows for extended battery life and increases autonomy and energy efficiency in IoT applications.

■ Motion detection using radar sensor

Due to the above features, radar sensors can be used for various purposes. However, the most widely used application is to detect the movement and presence of targets such as people, cars, and animals.

Motion detection plays a vital role in a variety of IoT applications such as security monitoring, energy management, human-computer interaction (e.g. gesture recognition), and medical monitoring (e.g. heart rate and respiration rate tracking).

The technology used to detect motion is the PIR (passive infrared) sensor. PIR motion sensors have been mainly used to detect people moving in a certain space.

This technology has been around for decades and is now so common that it can be found in everything from lighting fixtures to security systems and automatic doors.

However, PIR sensors have significant limitations in their implementation and use. These include false alarms caused by pets or other infrared radiators, interference from other sources operating in the same frequency band (e.g. TV remote controls), limited sensing range, and an inability to provide directional information.

In particular, PIR sensors must be in a straight line of sight to detect motion, and their detection range is limited to the area directly in front of the sensor.

Additionally, PIR sensors require large movements to be detected. For example, smart home devices often require the user to wave their hand vigorously in front of a PIR sensor to understand a command.

Radar technology alleviates these limitations by detecting motion.

For example, radar sensors can accurately tell whether people are present in a room for IoT applications, no matter how fast or how much they move.

Not only that, radar sensors are so precise that they can even detect a person’s breathing or heartbeat. This is something that PIR sensors cannot do, as they can only detect temperature changes when an object passes through their field of view.

■ 60GHz radar technology

Radar sensors operate at a variety of frequencies. Many radar technologies operate at 24 GHz, with bandwidths up to 250 MHz within the ISM (industrial, scientific, and medical) band for FMCW (Frequency Modulated Continuous Wave) radar operation.

This technology is mainly used in outdoor applications. Because it has a long detection range and is very robust against environmental influences (such as humidity).

The 24 GHz band is restricted to the ISM band, but an unlicensed bandwidth of 7 GHz can be used around 60 GHz.

Therefore, development has been done with 60GHz radar technology to implement more powerful applications and products.

This is especially true for applications that operate at high bandwidths and require proximity sensing at close range.

60GHz radar technology can detect motion and complex gestures with finer granularity and greater accuracy than 24GHz technology.

Therefore, 60GHz technology is suitable for applications such as occupancy detection at a distance, people tracking and classification, material classification, and human biometric detection.

Additionally, 60GHz radar technology is capable of detecting subtle motions, making it ideal for use in augmented reality (AR) and virtual reality (VR) applications that form the foundation of the metaverse.

For this reason, many manufacturers are already adopting 60GHz radar chipsets for their head mounted displays (HMDs).

■ Utilizing radar technology in smart home applications

Smart homes are the fastest growing segment in the IoT market. Smart homes can leverage radar technology to improve the functionality, accuracy, energy consumption, and cost of their applications.

In particular, the recent availability of low-cost, low-power radar sensors has enabled a new generation of smart home applications, from enhancing security and safety to enhancing convenience and comfort.

Some of the most common uses of radar in smart homes include:

- Automatic door control: Intuitive sensing using radar sensors can detect not only motion but also approaching and receding movements. This enables automatic door control applications. The door opens only when the target is detected to be approaching continuously, and does not open when other types of motion are detected.

- Occupancy detection: By adopting radar sensors in smart devices, it is possible to detect the presence or absence of people and detect movement, and various optimizations are possible. For example, if there is no one in the room, the radar-based smart device can automatically switch to sleep mode and save energy.

- Distinguishing and Tracking: Devices such as sound systems can use radar sensors to add smart features. For example, a sound system can track the location of the listener and continuously optimize the volume and sound parameters accordingly.

- Elderly care systems: Radar technology can be used to develop innovative elderly care applications. For example, a bed-out system can alert people when they get out of bed and don’t come back within a few minutes. Similarly, a chair departure system can alert you when a person leaves their chair and does not return within a set amount of time.

- Heating control system: It is possible to control the floor heating system using radar. It can detect whether there are people in the room and turn the heating on or off accordingly. Or it can track the distance and location of people in the room and adjust the fan speed and blade direction of the air conditioner. Such use cases not only increase the comfort of the occupants, but also improve the environmental impact and sustainability.

- Fall detection: Radar-based systems can also be used for fall detection. In this case, radar is installed on a wall or ceiling and a signal is continuously transmitted. Then, when a person falls off the bed, the reflected wave changes due to the change in posture. The radar system can detect this change and determine it as a fall.

- Monitoring vital signs: It is also possible to monitor breathing patterns and heart rate using radar technology. Over time, this information can be used to detect abnormalities in heart rate patterns. These heart rate pattern signals may indicate cardiac arrhythmias or other diseases. Heart rate pattern detection enables innovative applications that save lives by identifying irregularities in heartbeats, such as infant care or elderly care.

Most of these features are based on detecting human movement at a certain distance, even under poor lighting conditions.

Moreover, these features must be provided in a way that does not disturb people. Optical motion detectors installed on walls or ceilings should not trigger false alarms as people move freely around the home.

■ The era of intuitive sensing

As radar technology rapidly advances, new user-friendly IoT applications are becoming possible, permeating every aspect of our lives. This is ushering in an era of intuitive sensing.

Intuitive sensing enables simple, easy, and natural interactions with all kinds of smart devices.

Intuitive sensing should provide a strong foundation for applications that do not annoy the user, thereby making life more convenient, safer, greener, and more efficient.

Infineon is leading the way in intuitive sensing with autonomous, compact and user-friendly radar solutions.

This includes both 24GHz and 60GHz solutions . Infineon's XENSIV™ sensor family offers extremely precise radar sensors in a variety of configurations.

These products are suitable for a wide range of applications in the automotive, industrial and consumer markets, and implementations using XENSIV™ products can reduce development times and improve energy efficiency , thereby helping customers increase profitability and achieve sustainability goals.

Recent rapid advances in radar technology across the board are laying the foundation for enabling next-generation IoT applications that are accurate, user-friendly, and intuitive.

These IoT applications will enable increased functionality and improved environmental impact, and IoT device manufacturers and solution integrators will not be able to exclude radar technology when designing and developing applications.

※ Contribution
Infineon Technologies Korea Co., LLC

Infineon Technologies AG is a global semiconductor leader in the areas of power systems and the Internet of Things. Its products and solutions are driving decarbonization and digitalization. In the fiscal year 2022 (ending September 30), Infineon generated sales of €14.2 billion with approximately 56,200 employees worldwide. Infineon is listed on the Frankfurt Stock Exchange (ticker symbol: IFX) and in the USA on the over-the-counter market OTCQX International Premier (ticker symbol: IFNNY).