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11 Myths About Radar and Intelligent IoT

Dec. 4, 2023
Radar isn’t just for aircraft and self-driving cars. This article debunks some of the myths surrounding radar and reveals how radar is one of the essential sensors needed to enable intelligent IoT applications.

This article is part of the TechXchange: The Internet of Things (IoT).

What you'll learn:

  • How radar has become an essential ingredient in creating smarter IoT devices.
  • Why radar is a better option than passive-infrared sensing.
  • Advanced applications that can take advantage of radar.


Radar isn’t just for aircraft and self-driving cars. This article debunks some of the myths surrounding radar and reveals how radar is one of the essential sensors needed to enable intelligent IoT applications.

As intelligent IoT devices become smarter, they make our lives better, more efficient, safer, and more secure in a vast array of applications. Market demand for smart devices will continue to grow as the number of possible applications expands. In fact, according to Statista market research, the global IoT market will reach almost $1.6 trillion by 2025.

A key element in enabling smarter IoT devices is the sensors that enable devices to gather data from their surrounding environment. With the ability to “see,” “hear,” “smell,” “perceive,” and other novel perceptive capabilities, smart IoT applications can better understand and more proactively interact with their environment.

In particular, sensors enable IoT devices to learn more about the people who use them, as well as determine what they need and when they need it. With this information, smart IoT can transform a wide range of applications, including smart homes, security, industrial, medical, automotive, consumer, and more.

While many different types of sensors are available to use in smart devices, radar is one of the most powerful given the capabilities it makes possible. This article will address some of the myths that have arisen around radar and show how radar is one of the essential types of sensors for enabling intelligent IoT applications.

1. Radar is only for long-range applications like airplanes and self-driving cars.

Radar can be used in a great variety of ways. The most common application is to detect the presence and movement of objects. However, since radar was invented for air defense in 1935, advances in technology have allowed radar to be used in a wide range of IoT applications, from large-scale security monitoring in parking lots down to tracking small movements, such as monitoring a person’s heart rate.

2. Radar only detects distance/range to an object.

As an active radio-frequency (RF) technology, radar-based systems send out pulses and track their echoes to gather information. While these data provide the distance/range to an object, they can be used to determine much more about the object, including its size, speed, direction, and, with a little help from AI, its behavior. With the right setup, IoT that leverages radar can even track multiple objects simultaneously.

3. Infrared is the best motion-detection sensor.

While passive-infrared (PIR) sensing is the traditional sensor of choice for detecting motion, it has several limitations compared to radar-based sensing. Because of factors such as environmental infrared radiation and interference from other sources that operate on the same frequency, PIR sensing is limited in range and lacks directional information. PIR sensors also require a direct line of sight to detect motion.

Radar addresses all of those limitations while offering greater resolution and accuracy, enabling many new applications.

4. Radar can only detect big movements.

Based on the application, radar sensors can detect extremely small micro-movements, even those as small as a person breathing while standing still. This high level of resolution and accuracy enables a great variety of advanced capabilities and applications (see Myth #11).

5. Radar can only detect presence.

Because they require a significant movement to trigger, PIR sensors are limited in their ability to detect presence. This also impacts their ability to detect absence, or the lack of an object being present. Thus, issues arise in terms of people remaining still “disappearing” to the PIR sensor.

For example, a PIR sensor would only see a person sleeping when they rolled over. Radar, with its extraordinary resolution and accuracy that can detect actions as subtle as breathing, is able to detect people who aren’t even moving for long periods of time. Therefore, a radar sensor will know when there’s no person present to detect (i.e., absence). Absence detection is an important capability for use cases such as elder monitoring or turning off lights when a room is empty.

6. Radar requires a bulky sensor that the user can see.

Radar may bring images of large dishes to mind. However, modern radar chipsets have a small footprint, enabling them to be integrated into even IoT systems of relatively small size.

In addition, one of the key features of a radar sensor is that its high-frequency RF signal can pass through most materials, including plastic, glass, and wood. Thus, the sensor can be concealed behind the product enclosure or casing.  Conversely, a PIR-based device must have the sensor exposed and pointing in the direction over which it has coverage, potentially making the people being monitored feel uncomfortable.

With a radar sensor, OEMs have flexibility in how they design what their product looks like. Furthermore, because the sensor is hidden, radar-based designs are inherently non-intrusive, meaning people don’t even notice them.

7. Radar needs specific environmental conditions to operate.

Traditional PIR sensors require an environment that minimizes interference. Conditions such as too much sunlight can cause PIR sensors to falsely trigger. Radar is inherently robust under different environmental and climate conditions. It provides consistently reliable performance even with varying temperature or lighting.

8. Radar operates in only one frequency.

Radar sensors operate across different frequencies. The primary frequencies are 24 GHz and 60 GHz. Generally, 24-GHz radar, which is within the regulated ISM band and has a narrow bandwidth of 250 MHz, is used extensively outdoors since it offers high detection range and is extremely robust to environmental conditions, including humidity.

Applications requiring higher bandwidth and close proximity sensing will leverage 60-GHz radar, with its 7-GHz unregulated bandwidth. It can detect motion and complex micro-movements/gestures with greater granularity and accuracy than 24 GHz.

9. Radar consumes too much power for battery-operated devices.

Radar sensors are designed to consume little power, resulting in more efficient devices for greater sustainability and longer operating life for battery-powered applications. As a result, OEMs can use radar in a wide range of IoT applications that need considerable autonomy and energy efficiency.

10. Radar is too complex to implement in small devices.

Radar is at the forefront of low-cost and low-power technology without compromising performance or accuracy. Continuing innovation from companies such as Infineon has led to product lines like the XENSIV family of sensors, which include an array of precise radar sensors

Development resources accelerate time-to-market and deliver significant energy savings compared to other technologies. Radar is such an efficient technology within a small footprint that it’s already being integrated into head-mounted displays (HMD) for applications such as augmented reality (AR) and virtual reality (VR) where size, weight, and power efficiency are all critical.

11. Radar can’t be used in advanced applications.

Radar is an incredible flexible technology that’s already being used in many diverse applications:

  • Human detection: Because it can track size, radar is able to differentiate between a burglar prowling close to a house and the neighbor’s cat. This reduces false triggers typical of PIR sensors.
  • Presence/absence detection: In addition to detecting presence, radar can detect when no one is present. No more waving your hands to get the conference room lights to turn back on if you haven’t moved for a while.
  • Tracking and localization: Radar can identify where a person is located within a room. This could be used for high-end sound systems to adjust the speakers to always locate the “sweet spot” wherever the listener is currently located.
  • Automatic door control: Rather than opening a store door whenever a person walks by, radar enables automatic doors to open only when a person is continuously approaching with the intent to pass through the door.  
  • Advance elder care: Radar sensors in beds and chairs can track if a person has gotten up and not returned within a few minutes, thus triggering an alarm.
  • Fall detection: Radar sensors mounted to the ceiling could detect whether a person has fallen and can’t get up. This system is superior to active emergency call systems because it’s passive; i.e., the person needn’t even be conscious to allow the system to trigger an alarm to call for help.
  • Vital signs monitoring: Radar is accurate enough to track breathing patterns and heart rate. Possible applications include monitoring an elder or baby to track irregular heartbeat patterns and increase safety.
  • HVAC and lighting efficiency: Heating, cooling, and lighting can be turned on or off accordingly based on whether a person is detected in the room. Advanced systems could direct heating or cooling toward where the person is currently located to improve performance and sustainability.

Radar is a powerful enabler of pervasive and user-friendly IoT applications. With its high resolution and accuracy, radar supports “intuitive sensing” where users can have simple, effortless, and natural interactions with smart devices. Due to its power efficiency and the flexibility it brings to product design, radar will be an essential component of next-generation, non-obtrusive applications that make our lives easier, safer, efficient, and sustainable.

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