About this document Scope and purpose This application note describes the key features of Infineon’s BGT24LTR11 Shield, part of Infineon’s 24 GHz Distance2GoL radar system platform. The shield is the evaluation platform for the 24 GHz low-power transceiver chip BGT24LTR11.
Steps 4 to 6 to get started with the Distance2GoL demo board ............9 Figure 4 Steps 7 to 9 to get started with the Distance2GoL demo board ............10 Figure 5 BGT24LTR11 Shield board with main components and dimensions ..........12 Figure 6 Block diagram – Distance2GoL ......................14 Figure 7 Block diagram –...
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking List of tables List of tables Table 1 Distance2GoL (Software-Controlled FMCW) module performance specifications......11 Table 2 Baseband amplifier to MCU pin connections ................... 19 Table 3 Baseband amplifier components and settings ................
Introduction Introduction The Distance2GoL radar system is a demo platform for Infineon’s 24 GHz silicon-germanium (SiGe) BGT24LTR11 radar chipset. It consists of two boards – the microcontroller board: Radar Baseboard XMC4700, and a radar front-end board: BGT24LTR11 Shield. This document focuses on the BGT24LTR11 Shield assembled for a software-controlled Frequency Modulated Continuous Wave (FMCW) implementation.
PCB manufacturer and specific design rules imposed and components used. Overview The platform is a stack-up of two boards – BGT24LTR11 Shield (radar front end) and radar baseboard XMC4700 (for signal processing). The Distance2GoL radar system consists of the following key components: •...
The circuitry for the BGT24LTR11 Shield (Software-Controlled FMCW) is designed to perform human target range detection and tracking with low power consumption. In this approach, the BGT24LTR11 MMIC is controlled using a software-based open-loop concept. Frequency is measured periodically and VCO is tuned accordingly.
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Getting started Getting started This section provides a quick step-by-step process to get started with the Distance2GoL board. Some of the steps are optional, for going deeper into the analysis of the board, the firmware and the extracted signals.
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Getting started STEP 4 STEP 5 STEP 6 Optional Optional Download SW/HW package Connect board Firmware update • Open “ ”. • Insert the micro-USB • Download and install...
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Getting started STEP 7 STEP 8 ST EP 9 Optional Optional View and edit source code Radar GUI MATLAB interface • Download and install the • Disconnect micro-USB cable •...
Note: The above specifications are indicative values based on typical datasheet parameters of BGT24LTR11 and simulation of several other parameters (antenna characteristics and baseband section) and can vary from module to module. The numbers above are not guaranteed indicators for module performance for all operating conditions.
Overview The radar Shield is shown in Figure 5. It contains the following sections: • RF part – consists of the Infineon 24 GHz radar MMIC – BGT24LTR11 and includes micro-strip patch antennas for the TX and RX sections •...
Figure 6 shows the block diagram of the Distance2GoL system. It consists of the highly integrated 24 GHz transceiver IC BGT24LTR11 with 1 TX and 1 RX antenna. The hardware consists of two main parts: one Software- Controlled FMCW BGT24LTR11 Shield and one microcontroller unit with XMC4700.
The Radar Baseboard XMC4700 is powered via micro-USB connector, external 7 V power supply or LiPo battery. It also provides the supply for the BGT24LTR11 Shield via the connectors. An LDO (U6) is used on the BGT24LTR11 Shield to supply all the components. Figure 7 shows the power supply concept used in the system.
BGT24LTR11 – 24 GHz transceiver MMIC The heart of the sensor module is the highly integrated BGT24LTR11 24 GHz transceiver IC. Figure 10 shows the detailed block diagram of the MMIC. BGT24LTR11 is a radar MMIC for signal generation and reception, operating in the 24.000 GHz to 24.250 GHz ISM band.
Antennas The BGT24LTR11 Shield features a 4 x 1 array antenna for the transceiver and receiver sections. The antenna has a gain of 9.6 dBi and an opening angle of 28.5 x 81.8 degrees. Figure 11 shows the simulated 2D and 3D radiation pattern.
The BGT24LTR11 provides both in-phase and quadrature-phase Intermediate Frequency (IF) signals from its receiver. Depending on the target in front of the radar antennas, the analog output signal from the BGT24LTR11 chipset can be very low in amplitude (µV to mV range). To process these low-amplitude signals, it is necessary to amplify the IF signals.
Baseband frequency response for low-gain and high-gain stages Figure 14 shows the frequency response of the low- and high-gain stages. The BGT24LTR11 Shield allows the user to select either the low-gain (first stage only) or high-gain (first stage + second stage) mode depending on the target RCS and distance to be detected.
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Hardware description: BGT24LTR11 Shield IF stage Designator Gain Configurable components – Configurable components I section – Q section Stage 1 + Stage 2 U5A + U4A...
The Distance2GoL power consumption can be computed after calculating the current consumption of the BGT24LTR11 for chirping, the frequency check and recalibration, and the duty-cycling of the baseband section. Some exemplary power consumption calculations are shown in the table below:...
External pin header connectors The BGT24LTR11 Shield has the provision to connect multiple headers on the edge of the board. Figure 15 shows the pin headers on the PCB, and Table 7,Table 8, Table 9, Table 10, Table 11 and Table 12 describe the pins.
External headers (P4) – pin description Pin no. Signal name Pin description ARD_PWM_ ARD_VCC_PTAT: control signal to turn PTAT on/off ARD_TX_EN: control signal for turning the TX of BGT24LTR11 ARD_PWM on/off ARD_VCC_BGT_EN: control signal for turning the BGT24LTR11 ARD_PWM_ on/off (via Q1 PMOS) Table 11 External headers (P5) –...
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking External pin header connectors Pin no. Signal name Pin description ARD_ADC_5 DIV_OUT: Divider output signal Table 12 External headers (P6) – pin description Pin no. Signal name Pin description V_PTAT_S&H_EN...
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Measurement results Measurement results Human range detection and tracking The system is designed for use cases such as presence detection, motion detection, proximity sensing and direction of movement detection for a single human target in 1D. It enables detection and tracking of a human walking within a linear distance of over 20 m in an indoor or outdoor environment.
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Measurement results Temperature check for out-of-band emissions The Distance2GoL demo board is also tested inside a temperature chamber for the bandwidth and out of band emissions at the temperature limits of -40°, 25° and 85°C. Markers 1 and 2 are set to 24.000 GHz and 24.250 GHz (ISM band) on the spectrum analyzer.
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Measurement results Figure 19 Bandwidth check at -40° inside temperature chamber Application Note page 27 of 32 V1.0 2021-03-31...
Frequency band and regulations 24 GHz regulations Infineon’s BGT24LTR11 radar sensor operates in the globally available 24 GHz bands. There is an ISM band from 24 to 24.25 GHz. However, each country may have different regulations in terms of occupied bandwidth, maximum allowed radiated power, conducted power, spurious emissions, etc.
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Authors Authors Radar Application Engineering Team, Business Line “Radio Frequency and Sensors” Application Note page 29 of 32 V1.0 2021-03-31...
Distance2GoL (Software-Controlled FMCW) low-power radar shield using BGT24LTR11 for range detection and human tracking Revision history Revision history Document Date of release Description of changes version V1.0 2021-03-31 Initial version Application Note page 31 of 32 V1.0 2021-03-31...
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