Full Analog Microwave Sensor for Multiple Range Selection and Ultra-low Power Consumption

摘要

A microwave sensor adjusts its sensing range based on a range gate selected from multiple range gates. An active antenna module transmits a first FMCW signal toward a target based on the selected range gate and for receiving second FMCW signal reflected from the target. A modulating module is used for generating modulation signal. The bandwidth of the first FMCW signal depends on an amplitude of the modulation signal. A first demodulator is used for demodulating the first FMCW signal and the second FMCW signal to generate beat frequency. A second demodulator is used to demodulate the beat frequency signal to generate a Doppler signal. An indentifying circuit is used for generating a triggering signal based on a voltage difference between integral of the Doppler signal from an object within the rage gate and an integral of clutter.

主权项

1. A microwave sensor, comprising:
an active antenna module, for transmitting a first FMCW signal toward a target based on a sweep cycle and for receiving second FMCW signal reflected from the target; a modulating module electrically connected to the active antenna module, for generating a modulation signal for the active antenna module according to one range gate chosen from a plurality of range gates, bandwidth of the first FMCW signal being adjusted depending on an amplitude of the modulation signal, and the plurality of range gates corresponding to the bandwidth of a plurality of first FMCW signals one on one; a first demodulator electrically connected to the active antenna module, for demodulating a beat frequency signal based on a range gate, and the beat frequency signal comprising a frequency difference between the first FMCW signal and the second FMCW signal; a second demodulator electrically connected to the first demodulator, for demodulating the beat frequency signal to generate a Doppler signal, frequency of the Doppler signal being equal to a frequency difference between an up-sweep beat frequency and a down-sweep beat frequency; and an indentifying circuit electrically connected to the second demodulator, for generating a triggering signal based on a voltage difference between an integral of the Doppler signal from an object within the rage gate and an integral of a clutter.