Radar sensors make motion sensing applications more intelligent.
Infineon 60GHz radar sensor BGT60LTR11AIP,
You can make the system start only when motion is detected.


Autonomous radar sensors enable intelligent motion sensing applications such as lighting control, automatic door opening and closing, and security alarms.

Infineon's XENSIV™ 60GHz radar sensor, the BGT60LTR11AIP, is a Doppler motion sensor operating in the 60GHz Industrial, Scientific, and Medical (ISM) band and is a single-package radar solution. It is capable of autonomous operation, can detect people at a distance of up to 5 meters, and consumes less than 5 mW of power.

Highly integrated, it eliminates the need for complex antenna design, RF expertise, or radar signal processing. Furthermore, its ability to transmit and receive through non-metallic materials allows it to be concealed within products, bringing radar technology into everyday life.

By integrating this sensor into systems such as laptops, speakers, tablets, and TVs, the system can be activated only when motion is detected. The system can be put into sleep mode to save power when no motion is detected for a specified period of time, and can be activated by motion alone, without a keyword.

The figure above is a functional block diagram of the BGT60LTR11AIP monolithic microwave integrated circuit (MMIC). This MMIC package includes one transmit and one receive broadbeam antenna. The two antennas have horizontal and vertical half-power beamwidths of 80°, maximizing coverage.

Looking at the block diagram, a voltage-controlled oscillator (VCO) generates a 60 GHz radar signal, which is stabilized using a phase-locked loop (PLL). The transmit signal chain includes an intermediate power amplifier with adjustable output power, controlled via SPI. A power detector monitors the transmit power.

The BGT60LTR11AIP MMIC incorporates a low-noise quadrature receiver and a low-noise amplifier, which are connected to a quadrature homodyne downconversion mixer, resulting in excellent sensitivity. An RC polyphase filter receiving the internal VCO signal generates a quadrature local oscillator signal for the quadrature mixer.

The analog baseband consists of a sample-and-hold circuit for low-power duty cycle operation, followed by an externally configurable high-pass filter, variable gain amplifier (VGA), and low-pass filter.

Target detectors are analog comparators that generate pulses based on target movement in front of the radar. These detectors provide two digital output signals: one indicating the target's movement, and the other indicating the target's direction of movement, such as approaching or receding.

The detector circuit is highly flexible and reduces the possibility of false detection, with user-configurable hold times, hit counters, and detection thresholds. Hold time refers to the time the detector output remains on after target detection, while hit counters refer to the number of comparator output pulses required to determine a valid target detection.

The BGT60LTR11AIP MMIC provides four 4-state input pins, QS1 to QS4, to allow flexible setting of performance parameters while operating in autonomous mode.

Using QS2, users can select from four thresholds to increase or decrease detector sensitivity. Experienced radar users can also use the QS1 pin to select semi-autonomous and SPI operation modes. These modes can extract raw radar data and process the signals using custom algorithms via SPI to a PC or external microcontroller.

For external processing, this evaluation board can be connected to an Arduino MKR board or an Infineon radar baseboard (MCU7).

Infineon provides demo software and a radar graphical user interface to support the BGT60LTR11AIP MMIC platform. This graphical user interface can display and analyze captured data in both the time and frequency domains. The sensor complies with ETSI and FCC regulations.

◇ High ease of use

The BGT60LTR11AIP MMIC provides motion and direction information, and a state machine controls the device. This allows for easy radar utilization in fully autonomous mode.

The BGT60LTR11AIP, a compact 3.3mm x 6.7mm x 0.56mm MMIC, integrates two antennas in a two-layer laminate package, eliminating the need for complex antenna design. This MMIC allows the use of standard FR4 materials in PCB designs.

Additionally, the BGT60LTR11AIP MMIC requires only a low-noise voltage regulator, a 38.4MHz crystal oscillator, and external capacitors as supporting circuitry. Two LEDs indicate the operation of the radar sensor. Green means the target has been detected, red means the direction of motion has been detected.

This all-in-one solution facilitates easy system integration and rapid prototyping for product functionality evaluation. The demo board above is a turnkey solution that allows you to evaluate the features of this radar sensor MMIC. It can also be used in a system by simply connecting a power supply between the VCC and ground wires.

The BGT60LTR11AIP MMIC provides a small, integrated, and cost-effective solution to replace existing passive infrared sensors in low-power or battery-operated applications.



This article is a summary of the article ‘Autonomous Radar Sensor Enables Smart Motion Sensing’ contributed by Infineon Technologies Korea.