"Application Brief
Low Power mmWave Radar Solution Enables New
Functionality in Battery Powered Proximity Sensing
Products
Robert Tolbert
The goal of this applications brief is to inform
and educate partners and customers on the
advancements that Texas Instruments’ has made in
millimeter wave (mmWave) Radar sensing. The key
advancement discussed in this brief is the release
of the IWRL6432 low power 60 GHz mmWave radar
sensor that can run sensing applications from a
typical battery.
The Technology: What is mmWave Radar
Sensing?
mmWave is a radio frequency (RF) sensing
technology that works in the spectrum band between
30 GHz and 300 GHz. mmWave has a wavelength
of 1 millimeter up to 10 millimeters. Therefore, the
industry term most often used for the technology
is mmWave as a result of the aforementioned
wavelength. The sensing technology works by using
one or more RF transmitters to send short radio
pulses at pre-determined frequencies from an on-chip
frequency generator into an area. The radio pulses
reflect off objects in the area, and those reflections
are captured on the same integrated circuit (IC) by
one or more on-chip RF receivers. Information about
the reflected signal is then used to determine range,
velocity and angle of reflection of a person/object with
an unmatched level of accuracy and reliability. The
range is the distance of the object from the sensor.
While the velocity is the speed and direction of
movement of the object. Finally, the angle of reflection
is the angle at which the reflected signals return to
the sensor upon reflection. This information is used to
determine the precise location of the object relative to
the sensor and in a three-dimensional space.
As previously mentioned, mmWave is an RF
technology. Therefore, mmWave sensors are only
mildly susceptible to changes in or less than ideal
environmental conditions. Conditions such as bright
sunlight, darkness, rain, sleet, snow, smoke, fog, high
humidity, extreme high or extreme low temperatures
have little to no impact on the accuracy of a mmWave
radar sensor. As a result, radar can be used in all
kinds of applications, whether industrial, residential,
indoors or outdoors, where competing technologies
fail.
mmWave radar sensors detect people and protect
their identities. As an RF based sensing technology
the sensors do not return any visual nor identifying
information unique to a specific person or object. You
don't get a visual of the object or person. The radar
does not return any information that can compromise
someone's privacy beyond presence and number of
objects detected. Additionally, the radar can be easily
installed behind objects allowing the radar to run
invisibly, reliably and robustly. The radar can sense
through various media (e.g. glass, plastic, wood,
drywall of varying thickness and more). Therefore,
the radar can be placed behind a picture or behind
curtains, basically out of plain sight.
Figure 1. US Frequency Spectrum
IWRL6432: Low Power Use Cases/Products
To date, mmWave Radar sensing based products
for industrial use have been largely relegated
to line-powered applications. This limited radar’s
potential use-cases and product appeal despite the
performance advantages that the technology has over
competing technologies like Passive Infrared (PIR)
sensors. IWRL6432, with focus on high-performance
while consuming less power is set to change that.
Radar can supplement the camera in products like
home security cameras and video doorbells,
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Copyright © 2023 Texas Instruments Incorporated
adding functionality such as precise location
detection, low-power presence detection, human vs
non-human classification and person counting, while
reducing false detections/alarms. End equipment
developers can even decide to replace the camera
completely to allow the security solution to be placed
in areas where personal privacy is of concern and
non-visual observation is desired like bedrooms and
restrooms. The low-power consumption of the device
enables battery power too, further increasing the
areas where the device can be placed. Table 1 give
some use cases of battery powered radars.
Table 1. Functions/Applications/Power
Consumption
Function Performance Avg Power
Consumption
End
Equipment
Presence
Detection
7 meters
(localization) 2mW
Lighting
Control, Indoor
Occupancy
Sensors,
Thermostats,
Appliances
Motion
Detection 15 meters 10mW
Video Doorbell,
Home
Surveillance
Tracking and
Classification
3+ person
tracking 50mW
Doors/Gates,
Surveillance
with
classification
Indoor Occupancy Sensors and Radar Enabled
Lights & Fixtures can now be battery powered,
making installation possible nearly anywhere. Using
the radar, these products count and localize the
number of people in a room. Lighting and ventilation
systems, which previously only knew whether people
were present/not-present, become more efficient and
robust. Minor motion detection enabled by mmWave
radar sensor is a key feature in improving the
efficiency of these products. Using the IWRL6432,
motion is detected from the slightest movements
such as typing or breathing enabling more precise
monitoring of offices, hotel rooms etc.
Personal Electronics like laptops, earbuds, music
players and the like can also be outfitted with
the IWRL6432 due to low power consumption. For
example, laptops can now use radar for “on-looker”
presence detection to dim the display when there is
an unwanted presence within a specified area around
the user and not compromise the battery life of the
laptop.
Many new applications of radar can be realized with
the low power consumption, accurate and reliable
range, velocity and location information that the
IWRL6432 provides.
Figure 2. IWRL6432 Video Doorbell Demonstration
with Camera and Radar Shown
The Design: What Makes the Power so Low?
The IWRL6432 is developed in Texas Instruments
low power 45nm RFCMOS process to enable
unprecedented levels of integration and power
consumption. This radar sensor deploys a mix of
hardware design and software techniques to minimize
the power consumption while in active and sleep
modes. The radar IC is partitioned into four (4) power
domains (see Figure B below) which can be turned
on/off via software controls.
1. RF / Analog Subsystem – includes all RF and
analog components required to transmit and
receive RF signals
2. Front-end Controller Sub-system: includes the
processor responsible for radar front-end
configuration, control and calibration
3. Application Sub-system: includes the ARM
Cortex®-M4, clocking and power managements
sub-blocks
4. Hardware Accelerator Sub-system: includes the
FFT and Constant False Alarm Rate (CFAR)
accelerators for scaling and compression
The device also features the capability to exercise
various low-power states like sleep and deep sleep.
Low-power sleep mode is achieved by clock gating
and by turning off specified internal blocks of the
device. The power states and their associated
description are listed in Table 2 below and include
Active, Processing, Idle and Deep Sleep States. In an
effort to maximize performance and minimize power
consumption the device can go in/out of the various
modes extremely quickly. IWRL6432 also includes
features such as memory retention while in low power
states to retain some contents of the on-chip memory
like the RF chirp profile and the application image.
Texas Instruments provides detailed documentation
and examples on how to navigate the IWRL6432
through the device's multiple power modes and
states. Take a look at the device data sheet and other
www.ti.com
2 Low Power mmWave Radar Solution Enables New Functionality in Battery
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design materials in the IWRL6432 product folder to
get more detailed information.
Table 2. IWRL6432 Device Power States
Mode Description
Active RF activity is present
Processing Data is being processed and
the RF / Analog Sub-system is
turned off
Idle State occurs during inter-frame/
inter-burst/inter-chirp idle time
Deep Sleep Lowest possible power state of
the device where the contents of
the device can be retained and
the device need not boot from
scratch
Conclusion
As buildings, homes, factories and personal
electronics get smarter the bar is raised on the
sensing requirements and modalities while keeping
power consumption to a minimum. The IWRL6432
meets the bar in enabling robust, reliable, accurate
high-performance sensing solutions with limited power
consumption. To learn more, visit www.ti.com/product/
IWRL6432
www.ti.com
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how can I cite the above in IEEE format? What is the type?