| 摘要 |
A microwave sensor is disclosed. The microwave sensor includes an active antenna module, a first low pass filter, a second demodulator, a modulation module, and a discrimination control module. The active antenna module is utilized for transmitting a first FMCW signal towards a target and receiving a second FMCW signal reflected back from the target according to a sweep period. The active antenna module includes a loop antenna and a radio frequency transistor. The first low pass filter and the radio frequency transistor form a first demodulator. The first demodulator and the second demodulator perform two-stage down converting and demodulating to extract information for calculating range and velocity, respectively. The present invention adjusts a radio frequency bandwidth of the FMCW signal by first adjusting an amplitude of a modulation signal generated by the modulation module to control various detection ranges. |
| 主权项 |
1. A microwave antenna, comprising:
an active antenna module utilized for transmitting a first frequency modulation continuous wave signal towards a target and receiving a second frequency modulation continuous wave signal reflected back from the target according to a sweep period, the active antenna module comprising:
a loop antenna comprising a transmitting terminal and a receiving terminal, the transmitting terminal being utilized for transmitting the first frequency modulation continuous wave signal, and the receiving terminal being utilized for transmitting the second frequency modulation continuous wave signal; anda radio frequency transistor, the radio frequency transistor comprising a control port, a first port, and a second port, the second port being coupled to the transmitting terminal, the control port being coupled to the receiving port, and the control port and the second port being out of phase; a first low pass filter electrically connected to the first port of the radio frequency transistor, the first low pass filter and the radio frequency transistor forming a first demodulator, the first demodulator being utilized for demodulating a beat signal based on a range gate, and the beat signal having a frequency equal to a difference between frequencies of the first frequency modulation continuous wave signal and the second frequency modulation continuous wave signal; a second demodulator electrically connected to the first port of the radio frequency transistor, the second demodulator being utilized for demodulating the beat signal to generate a Doppler signal, a frequency of the Doppler signal being equal to a difference between an up-sweep beat frequency and a down-sweep beat frequency; a modulation module electrically connected to the active antenna module, the modulation module being utilized for generating a modulation signal to the active antenna module based on a range gate selected from a plurality of range gates, a bandwidth of the first frequency modulation continuous wave signal being adjusted according to an amplitude of the modulation signal, and each of the plurality of range gates being corresponding to one of the bandwidths of the first frequency modulation continuous wave signal; and a discrimination control module electrically connected to the modulation module, the discrimination control module being utilized for bypassing a calculation for the target if the target being located outside the range gate, and calculating a range between the microwave sensor and the target based on the beat signal and a moving velocity of the target based on the frequency of the Doppler signal if the target being located inside the range gate. |
