Application Note
page 16 of 32
V1.0
2021-03-31
Distance2GoL (Software-Controlled FMCW) low-power radar shield using
BGT24LTR11 for range detection and human tracking
Hardware description: BGT24LTR11 Shield
Radar front-end
shielding
DC blocks
Harmonics
filter
BGT24LTR11
Compensation
structures (stubs)
RX
TX
Figure 9
RF front-end overview (top)
4.6
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. It is based on a 24 GHz fundamental Voltage Controlled
Oscillator (VCO).
Figure 10
Block diagram
–
BGT24LTR11 MMIC
A built-in voltage source delivers a VCO PTAT tuning voltage. When connected to the VCO tuning pin, it
compensates for the inherent frequency drift of the VCO overtemperature, thus stabilizing the VCO within the
ISM band and eliminating the need for a PLL/microcontroller.
The receiver section uses a Low Noise Amplifier (LNA) in front of a quadrature homodyne down-conversion
mixer to provide excellent receiver sensitivity. Derived from the internal VCO signal, a RC Poly-Phase Filter (PPF)
generates quadrature LO signals for the quadrature mixer. I/Q IF outputs are available through single-ended
terminals.
