Frequency-modulated continuous wave radar device and method for detecting vital information and humidity

Abstract

A frequency-modulated continuous wave radar device and a method for detecting life information and humidity are disclosed. The method includes transmitting an incident radar signal to a field to detect a reflected radar signal reflected by an object under test and a reflected radar signal reflected by a humidity sensing tag, thereby obtaining life information of the object under test and humidity information detected by the humidity sensing tag.

Description

TECHNICAL FIELD

[0001] The present application relates to a radar signal processing technique, in particular to a frequency-modulated continuous wave radar device and a life information and humidity detection. BACKGROUND

[0002] Although there are physiological information detection radars for detecting respiration and heartbeat, they cannot detect the wetness of diapers worn by patients, the elderly, and infants in applications such as patient care, elderly care, and infant care. SUMMARY

[0003] According to some embodiments, a life information and humidity detection method includes: transmitting an incident radar signal to a field and receiving a corresponding reflected radar signal of the field, wherein the incident radar signal includes a plurality of linearly modulated frequency signals; demodulating the reflected radar signal according to the incident radar signal to obtain a first intermediate frequency signal; demodulating the reflected radar signal according to a double-frequency incident radar signal to obtain a second intermediate frequency signal; processing the first intermediate frequency signal to obtain life information of a to-be-detected object; and obtaining humidity information according to an energy peak time point of the second intermediate frequency signal.

[0004] According to some embodiments, a frequency-modulated continuous wave radar device includes a transmitting unit, a receiving unit, a first demodulating unit, a second demodulating unit, and a processing unit. The transmitting unit is configured to transmit an incident radar signal to a field, wherein the incident radar signal includes a plurality of linearly modulated frequency signals. The receiving unit is configured to receive a corresponding reflected radar signal of the field. The first demodulating unit is coupled to the transmitting unit and the receiving unit and is configured to demodulate a first intermediate frequency signal from the reflected radar signal and the incident radar signal. The second demodulating unit is coupled to the transmitting unit and the receiving unit and is configured to demodulate a second intermediate frequency signal from the reflected radar signal and a double-frequency incident radar signal. The processing unit is coupled to the transmitting unit, the receiving unit, and the demodulating unit and is configured to process the first intermediate frequency signal to obtain life information of a to-be-detected object and to obtain humidity information according to an energy peak time point of the second intermediate frequency signal.

[0005] According to some embodiments, a frequency-modulated continuous wave radar device includes a transmitting unit, a receiving unit, a first demodulating unit, a second demodulating unit, and a processing unit. The transmitting unit is configured to transmit two incident radar signals with first and second frequency-modulated frequency bands to a field, respectively, wherein the two incident radar signals include a plurality of linearly frequency-modulated signals. The receiving unit is configured to receive a reflected radar signal corresponding to the field. The first demodulating unit is coupled to the transmitting unit and the receiving unit, receives the incident radar signal with the first frequency-modulated frequency band, and is configured to demodulate a first intermediate frequency signal from the reflected radar signal and the incident radar signal with the first frequency-modulated frequency band. The second demodulating unit is coupled to the transmitting unit and the receiving unit, receives the incident radar signal with the second frequency-modulated frequency band, and is configured to demodulate a second intermediate frequency signal from the reflected radar signal and the incident radar signal with the second frequency-modulated frequency band. The processing unit is coupled to the transmitting unit, the receiving unit, and the demodulating unit, and is configured to process the first intermediate frequency signal to obtain life information of an object under test, and obtain humidity information according to an energy peak time point of the second intermediate frequency signal.

[0006] In summary, the frequency-modulated continuous wave radar device and the method for detecting life information and humidity according to some embodiments can measure life information and humidity simultaneously, thereby saving device space and hardware cost. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 A use state diagram of the frequency-modulated continuous wave radar device according to some embodiments;

[0008] Figure 2 An architecture diagram of the frequency-modulated continuous wave radar device according to some embodiments;

[0009] Figure 3 A flowchart of the method for detecting life information and humidity according to some embodiments;

[0010] Figure 4 A diagram of demodulating the first intermediate frequency signal according to an embodiment;

[0011] Figure 5 An architecture diagram of the humidity sensing tag according to an embodiment;

[0012] Figure 6 A structure diagram of the humidity detection antenna according to an embodiment;

[0013] Figure 7 A structure diagram of the humidity sensor according to an embodiment;

[0014] Figure 8 A structure diagram of the humidity sensor according to another embodiment;

[0015] Figure 9 A Figure 6Frequency response graphs of the humidity detecting antenna under different humidity environments.

[0016] Figure 10 For Figure 6 A graph of the resonance frequency of the humidity detecting antenna versus relative humidity.

[0017] Figure 11 A schematic diagram of demodulating a second intermediate frequency signal for an embodiment.

[0018] Figure 12 A schematic diagram of time division multiplexing for some embodiments.

[0019] Symbol explanation

[0020] 100: frequency-modulated continuous wave radar device

[0021] 111: transmitting unit

[0022] 112: receiving unit

[0023] 123: first demodulation unit

[0024] 124: second demodulation unit

[0025] 130: processing unit

[0026] 136: analog-to-digital converter

[0027] 137: processor

[0028] 140: signal generator

[0029] 200: humidity sensing tag

[0030] 210: input antenna

[0031] 220: frequency multiplication circuit

[0032] 230: RF-DC converter

[0033] 240: oscillator

[0034] 250: output antenna

[0035] 258: end point

[0036] 260: humidity sensor

[0037] 261, 262: parallel plates

[0038] 263: upper ring

[0039] 264: lower ring

[0040] 900: object to be measured

[0041] FH: incident radar signal

[0042] FN, FN': reflected radar signal

[0043] Sp1-Sp6: microstrip line

[0044] S31-S36: step

[0045] R1, R2, R bias : resistance

[0046] C1, C2: capacitance

[0047] D1: diode

[0048] G1, G2: inverter

[0049] L, L inset : length

[0050] W: width

[0051] B: pulse bandwidth

[0052] S: modulation slope

[0053] T: parameter

[0054] Tc: time period

[0055] fc: modulation start frequency

[0056] CH1, CH2: linearly modulated frequency signal DETAILED DESCRIPTION

[0057] As used herein, the term "coupled" means two or more elements are in direct physical or electrical contact with one another, or are not in direct contact with one another, unless otherwise indicated herein.

[0058] Referring to Figure 1 is a use state diagram of a frequency modulated continuous wave (FMCW) radar device 100 according to some embodiments. The frequency modulated continuous wave radar device 100 transmits a radar signal (hereinafter referred to as "incident radar signal FH"). The incident radar signal FH is transmitted to a field, and is reflected back to the frequency modulated continuous wave radar device 100 by an object to be measured 900, a humidity sensing tag 200, an environment, etc. The radar signal reflected by the object to be measured 900 is hereinafter referred to as "reflected radar signal FN", and the radar signal reflected by the humidity sensing tag 200 is hereinafter referred to as "reflected radar signal FN' ".

[0059] Referring to Figure 2 and Figure 3 , Figure 2 is a schematic diagram of an architecture of a frequency modulated continuous wave radar device 100 according to some embodiments, Figure 3A flowchart of a method for detecting vital information and humidity according to some embodiments. The frequency-modulated continuous wave radar device 100 comprises a transmitting unit 111, a receiving unit 112, a first demodulating unit 123, a second demodulating unit 124, a processing unit 130 and a signal generator 140. The processing unit 130 is coupled to the transmitting unit 111, the receiving unit 112, the first demodulating unit 123 and the second demodulating unit 124 to control these units. The processing unit 130 comprises two analog-to-digital converters 136 and a processor 137. The signal generator 140 generates a linearly modulated frequency (chirp) signal (as shown in Figure 4 The transmitting unit 111 is configured to transmit an incident radar signal FH (step S31). The transmitting unit 111 comprises a transmitting antenna and a power amplifier (not shown). After receiving the linearly modulated frequency signal generated by the signal generator 140, the transmitting unit 111 amplifies the signal via the power amplifier and transmits the signal via the transmitting antenna. Therefore, the transmitting antenna is designed to work effectively in the frequency range of the incident radar signal FH. In this embodiment, the transmitting antenna can be a patch antenna, but the present application is not limited to this.

[0060] The receiving unit 112 is configured to receive a reflected radar signal FN, FN' (step S32). The receiving unit 112 comprises a receiving antenna, and the frequency range of the receiving antenna should cover the frequency of the reflected radar signal FN, FN'. Alternatively, when the frequency range of a receiving antenna can cover the frequency of the reflected radar signal FN, FN', one receiving antenna is enough. Otherwise, two receiving antennas can be used, and each of them works in a different frequency range to cover the frequency of the reflected radar signal FN, FN', respectively. It is understood that if only the reflected radar signals FN, FN' with the same frequency are received, only one receiving antenna can be used.

[0061] The first demodulating unit 123 and the second demodulating unit 124 are coupled to the transmitting unit 111 and the receiving unit 112, and are configured to demodulate the reflected radar signals FN, FN' respectively to obtain a first intermediate frequency signal and a second intermediate frequency signal (steps S33, S35). The two analog-to-digital converters 136 are coupled to the outputs of the first demodulating unit 123 and the second demodulating unit 124, respectively, and are coupled to the processor 137. After the first intermediate frequency signal and the second intermediate frequency signal are converted into digital signals by the two analog-to-digital converters 136, the signals are processed by the processor 137. According to the first intermediate frequency signal, the vital information of the object 900 can be obtained (step S34). According to the second intermediate frequency signal, the humidity information can be obtained (step S36). Thus, the frequency-modulated continuous wave radar device 100 can obtain the vital information and the humidity information. For example, in the application of baby care, the vital reaction and the diaper condition of the baby can be obtained simultaneously, but the present application is not limited to this application.

[0062] Referring to Figure 4 Fig. 4 is a schematic diagram illustrating a first intermediate frequency signal obtained by demodulating a frequency modulated signal according to an embodiment. Here, only one frequency modulated signal is shown, but the incident radar signal FH should include a plurality of frequency modulated signals. The frequency of the frequency modulated signal increases linearly with time from a modulated start frequency fc to a modulated end frequency over a time period Tc. The difference between the modulated start frequency fc and the modulated end frequency is the pulse bandwidth B. The modulated slope is S. In some embodiments, the modulated start frequency fc is 24 GHz or 77 GHz, but the present application is not limited thereto. After the incident radar signal FH is reflected, the receiving unit 112 receives the reflected radar signal FN, which can be regarded as a delayed version of the incident radar signal FH. The first demodulation unit 123 couples the incident radar signal FH and the reflected radar signal FN to obtain a coupled signal of the difference in frequency of the two, i.e. an intermediate frequency signal. After the intermediate frequency signal is obtained, bandpass filtering can be performed to filter out high frequency signals. For the sake of distinction, the intermediate frequency signal obtained by the first demodulation unit 123 is referred to as the first intermediate frequency signal. It can be seen that the frequency value IF1 of the first intermediate frequency signal is a constant value, and the frequency value IF1 varies with the time point at which the reflected radar signal FN is received. That is, the frequency value IF1 of the first intermediate frequency signal can reflect the distance between the frequency modulated continuous wave radar device 100 and the object 900 to be measured. Therefore, in step S34, the first intermediate frequency signal is converted into a digital signal using the analog-to-digital converter 136. Then, the digital signal is subjected to a fast Fourier transform (hereinafter referred to as a range Fourier transform) by the processor 137, and the distance information of the object 900 to be measured can be obtained. Next, the phase information can be obtained by the processor 137 performing a Doppler fast Fourier transform, and thus the vital information of the object 900 to be measured can be obtained. Before performing the fast Fourier transform, signal processing such as noise removal, high frequency signal removal, and inappropriate respiratory harmonic removal can be performed.

[0063] Before describing the processing of the second intermediate frequency signal (i.e. the intermediate frequency signal obtained by demodulation by the second demodulation unit 124), the architecture of the humidity sensing tag 200 will be described. Referring to Figure 5 Fig. 5 is a schematic diagram illustrating the architecture of the humidity sensing tag 200 according to an embodiment. The humidity sensing tag 200 includes an input antenna 210, a frequency multiplication circuit 220, an RF-DC converter 230, an oscillator 240, an output antenna 250, and a humidity sensor 260.

[0064] The input antenna 210 is used to receive the incident radar signal FH transmitted from the frequency modulated continuous wave radar device 100. In this embodiment, the input antenna 210 is a dual dipole patch antenna, but the present application is not limited thereto. The input antenna 210 is coupled to a frequency doubler 220 and an RF-DC converter 230. The frequency doubler 220 receives the incident radar signal FH received by the input antenna 210 and doubles the frequency of the incident radar signal FH, i.e. generates a signal with frequency 2f0 from the incident radar signal FH with frequency f0 (or base frequency signal). The RF-DC converter 230 is an energy harvester that harvests the energy of the incident radar signal FH received by the input antenna 210. A portion of the RF signal energy is harvested by the RF-DC converter 230 and boosted to the operating voltage of the other circuits to provide the operating voltage of the humidity sensing tag 200. Thus, the humidity sensing tag 200 does not need to be equipped with an additional battery. However, in some embodiments, a battery can be equipped to replace the RF-DC converter 230 to provide the operating voltage of the circuits. The RF-DC converter 230 can be mainly implemented by a voltage multiplier composed of a plurality of diodes and a plurality of capacitors. The RF-DC converter 230 is also coupled to an oscillator 240 to supply the operating voltage to the oscillator 240. The oscillator 240 is coupled to the bias terminal of the frequency doubler 220 to generate a specific frequency signal to modulate the signal of the frequency doubler 220. The specific frequency signal can be used as the tag identification. Figure 5 is an example of the composition of the oscillator 240, which can be implemented by the elements of inverter G1, G2, resistor R1, R2 and capacitor C1, but the present application is not limited thereto.

[0065] Figure 5 is also an example of the composition of the frequency doubler 220, but the present application is not limited thereto. The frequency doubler 220 is composed of diode D1, a plurality of microstrip lines Sp1-Sp6, resistor R bias and capacitor C2. The input terminal of the diode D1 is coupled to the microstrip lines Sp1, Sp3, resistor R bias and capacitor C2, and the capacitor C2 is used as a bypass capacitor to filter the base frequency signal (f0). The output of the frequency doubler 220 can be started or stopped by adjusting the bias voltage of the diode D1. The resistor R bias serves as a bias resistor and is coupled to the oscillator 240 to control the modulation of the frequency doubler 220. The output terminal of the diode D1 is coupled to the microstrip lines Sp2, Sp4, Sp5, Sp6, which form a high-pass filter to filter the base frequency signal (f0). In this embodiment, the length of the microstrip line Sp3 is one-quarter of the wavelength of the base frequency signal, and the lengths of the microstrip lines Sp4, Sp5, Sp6 are one-quarter of the wavelength of the doubled frequency signal.

[0066] The output antenna 250 is coupled to the frequency doubling circuit 220 to transmit the modulated and frequency-doubled radio frequency signal, i.e., the output coupling is a frequency-doubled signal (2f0) of the specific frequency signal for tag identification. The output antenna 250 is coupled to the humidity sensor 260 to form a humidity detection antenna. The humidity sensor 260 is a variable capacitor. The change of the medium caused by humidity will affect the dielectric constant of the capacitor, and further affect the resonant frequency of the output antenna 250, so that the energy intensity of the frequency-doubled signal (2f0) changes. Therefore, the frequency-modulated continuous wave radar device 100 can detect the change of humidity by detecting the change of the signal intensity of the frequency-doubled signal (2f0). The humidity sensor 260 can be an interdigital capacitor or a parallel plate capacitor.

[0067] Referring to Figure 6 Fig. 4 is a structural schematic diagram of a humidity detection antenna according to an embodiment. The end point 258 is the signal feeding end of the output antenna 250, which receives the signal of the frequency doubling circuit 220. The output antenna 250 is a patch antenna here, with a length L of 37.5 cm and a width W of 51 cm. The feeding section has a length L of 9.5 cm. The humidity sensor 260 is an interdigital capacitor, which has 18 interlaced interdigital electrodes, each with a length of 5 cm, a width of 0.6 cm, and a spacing of 0.3 cm. The above specifications are only examples, and the present application is not limited thereto. inset Fig. 4 is a structural schematic diagram of a humidity detection antenna according to an embodiment. The end point 258 is the signal feeding end of the output antenna 250, which receives the signal of the frequency doubling circuit 220. The output antenna 250 is a patch antenna here, with a length L of 37.5 cm and a width W of 51 cm. The feeding section has a length L of 9.5 cm. The humidity sensor 260 is an interdigital capacitor, which has 18 interlaced interdigital electrodes, each with a length of 5 cm, a width of 0.6 cm, and a spacing of 0.3 cm. The above specifications are only examples, and the present application is not limited thereto.

[0068] Referring to Figure 7 Fig. 5 is a structural schematic diagram of the humidity sensor 260 according to an embodiment. Here, the humidity sensor 260 is a parallel plate capacitor, which has two parallel plates 261, 262 spaced apart vertically.

[0069] Referring to Figure 8 Fig. 6 is a structural schematic diagram of the humidity sensor 260 according to another embodiment. Here, the humidity sensor 260 is a ring-shaped interdigital capacitor, which includes an upper ring 263 and a lower ring 264 arranged in a ring-shaped interlaced and spaced manner.

[0070] Referring to Figure 2 and Figure 3The first demodulation unit 123 is configured to demodulate the reflected radar signal FN reflected by the object under test 900. Therefore, the frequency of the reflected radar signal FN is the same as that of the incident radar signal FH, both being f0. The second demodulation unit 124 is configured to demodulate the reflected radar signal FN' backscattered by the humidity sensing tag 200. As previously explained, the frequency of the reflected radar signal FN' is 2f0. The second demodulation unit 124 is coupled to the transmitting unit 111 and the receiving unit 112. It receives the frequency-doubled incident radar signal FH (2f0) from the transmitting unit 111 and is configured to demodulate the reflected radar signal FN' according to twice the frequency (2f0) of the incident radar signal FH to obtain a second intermediate frequency signal. Here, the transmitting unit 111 includes a frequency multiplier to generate the frequency-doubled signal 2f0 (step S35).

[0071] Next, step S36 will be explained, which describes how humidity information is obtained using the second intermediate frequency signal. Similar to the first demodulation unit 123 mentioned above, after the second demodulation unit 124 obtains the second intermediate frequency signal, it can also perform bandpass filtering to filter out high-frequency signals. Since the demodulation is performed using a double frequency, the double frequency signal responded by the non-humidity sensing tag 200 has been filtered out, and only the response signal of the humidity sensing tag 200 is retained. Information unrelated to the humidity sensing tag 200 will not be extracted.

[0072] Reference Figure 9 ,for Figure 6 The frequency response diagram of the humidity detection antenna under different humidity environments is shown. It can be seen that when dry, the reflected radar signal FN' is strong due to the good tuning of the antenna circuit. When humid, the reflected radar signal FN' weakens due to the poor tuning of the antenna circuit. However, regardless of the humidity, the reflected radar signal FN' is strongest at the resonant frequency. The resonant point is the location of the energy peak. The frequency of this resonant point changes with the humidity of the humidity detection antenna.

[0073] Reference Figure 10 ,for Figure 6 The diagram shows the relationship between the resonant frequency of the humidity detection antenna and relative humidity. After a certain humidity level is exceeded (e.g., above 55%), the resonant frequency corresponds to the relative humidity. Therefore, if the current resonant frequency of the humidity detection antenna can be found, the current humidity can be determined.

[0074] Reference Figure 11Fig. 6 shows a diagram of a second intermediate frequency signal according to an embodiment. The resonance frequency to be found is assumed to be 2fo. It can be found that, using a linear relationship, the resonance frequency 2fo can be deduced from the time point of the resonance frequency 2fo, as long as the time point of the resonance frequency 2fo is known. The resonance point is the position of the energy peak. Therefore, by analyzing the energy peak of the second intermediate frequency signal, the time point of the resonance frequency can be found, and the parameter T can be obtained. The parameter T is the time period from the start time of the reflected radar signal FN' to the time point of the energy peak. Accordingly, the resonance frequency 2fo can be obtained. Further, by using the resonance frequency 2fo, the relationship between the resonance frequency and the humidity as shown in Fig. 7 can be found, and the humidity information can be obtained. In some embodiments, the processor 137 can store a lookup table or a function for querying. Figure 10

[0075] In some embodiments, the processor 137 can further perform a range fast Fourier transform and a Doppler fast Fourier transform on the second intermediate frequency signal to obtain an identification signal (a specific frequency generated by the oscillator 240 as a tag identification) of the humidity sensing tag 200.

[0076] In some embodiments, the transmitting unit 111 can transmit two incident radar signals FH with a first frequency modulation band and a second frequency modulation band. In some embodiments, a frequency band commonly used by radar for measuring life information, such as 24 GHz or 77 GHz, can be used as the frequency of the incident radar signal FH that can obtain the first intermediate frequency signal. In this way, the detection sensitivity can be improved. On the other hand, the 865-868 MHz frequency band suitable for tag use is used as the frequency of the incident radar signal FH that can obtain the second intermediate frequency signal. In this case, the antenna of the transmitting unit 111 includes a millimeter wave antenna (such as an Antipodal Vivaldi antenna) and a ultra high frequency (UHF) band antenna.

[0077] Referring to Figure 12 Fig. 8 shows a diagram of a time division multiplexing according to some embodiments. The two incident radar signals FH of the third embodiment can be transmitted in a time division duplexing manner. In a first mode, the incident radar signal FH that can obtain the first intermediate frequency signal includes a plurality of linearly modulated frequency signals CH1, and in a second mode, the incident radar signal FH that can obtain the second intermediate frequency signal includes a plurality of linearly modulated frequency signals CH2.

[0078] ​In some embodiments, the processor 137 can be, for example, a central processing unit (CPU), a graphics processing unit (GPU), or other programmable general purpose or special purpose microprocessors (Microprocessor), digital signal processors (DSP), programmable controllers, application specific integrated circuits (ASIC), programmable logic devices (PLD) or other similar devices, chips, integrated circuits, and combinations thereof.

[0079] In summary, the frequency-modulated continuous wave radar device and the method for detecting vital information and humidity according to some embodiments can measure vital information and humidity at the same time, saving device space and hardware costs.

Claims

1. A method for detecting vital signs and humidity, comprising: The system transmits incident radar signals to the field and receives corresponding reflected radar signals from the field, wherein the incident radar signals include multiple linearly modulated frequency signals. Demodulate the reflected radar signal based on the incident radar signal to obtain the first intermediate frequency signal; The reflected radar signal is demodulated based on the incident radar signal at twice the frequency to obtain the second intermediate frequency signal; The first intermediate frequency signal is processed to obtain the life information of the object under test; and Humidity information is obtained based on the peak energy time point of the second intermediate frequency signal.

2. The method for detecting vital information and humidity as described in claim 1, wherein before obtaining the humidity information, the resonant frequency is first obtained based on the energy peak time point, so as to obtain the humidity information based on the resonant frequency.

3. The method for detecting vital signs and humidity as described in claim 2, wherein the resonant frequency is 2fc + T × 2S, where fc is the initial frequency of the linearly modulated frequency signal, T is the period from the start time of the reflected radar signal to the peak energy time point, and S is the modulation slope of the linearly modulated frequency signal.

4. The method for detecting vital information and humidity as described in claim 2, wherein the humidity information is obtained by finding the relationship between the resonant frequency and humidity based on the resonant frequency.

5. The method for detecting vital information and humidity as described in claim 1, wherein the vital information is obtained by performing a distance fast Fourier transform and a Doppler fast Fourier transform on the first intermediate frequency signal.

6. The method for detecting vital signs and humidity as described in claim 1, further comprising: The identification signal of the humidity sensing tag is obtained by performing distance fast Fourier transform and Doppler fast Fourier transform on the second intermediate frequency signal.

7. A frequency-modulated continuous wave radar device, comprising: The transmitting unit is configured to transmit an incident radar signal to the field, wherein the incident radar signal includes multiple linearly modulated frequency signals; The receiving unit is configured to receive the reflected radar signal corresponding to the field. The first demodulation unit, coupled to the transmitting unit and the receiving unit, is configured to demodulate a first intermediate frequency signal based on the reflected radar signal and the incident radar signal. The second demodulation unit, coupled to the transmitting unit and the receiving unit, is configured to demodulate the second intermediate frequency signal based on the reflected radar signal and the incident radar signal at twice the frequency. and The processing unit, coupled to the transmitting unit, the receiving unit, the first demodulation unit, and the second demodulation unit, is configured to process the first intermediate frequency signal to obtain the life information of the object under test, and to obtain humidity information based on the energy peak time point of the second intermediate frequency signal.

8. A frequency-modulated continuous wave radar device, comprising: The transmitting unit is configured to transmit two incident radar signals with a first frequency modulation band and a second frequency modulation band to the field, respectively, wherein the two incident radar signals include multiple linearly modulated frequency signals; The receiving unit is configured to receive the reflected radar signal corresponding to the field. The first demodulation unit is coupled to the transmitting unit and the receiving unit, receives the incident radar signal having the first frequency modulation band, and is configured to demodulate the first intermediate frequency signal based on the reflected radar signal and the incident radar signal having the first frequency modulation band. The second demodulation unit is coupled to the transmitting unit and the receiving unit, receives the incident radar signal having the second frequency modulation band, and is configured to demodulate the second intermediate frequency signal based on the reflected radar signal and the incident radar signal having the second frequency modulation band. and The processing unit, coupled to the transmitting unit, the receiving unit and the demodulation unit, is configured to process the first intermediate frequency signal to obtain the life information of the object under test, and to obtain humidity information based on the energy peak time point of the second intermediate frequency signal.

9. The frequency modulation continuous wave radar device as described in claim 8, wherein the antennas of the transmitting unit are a millimeter-wave antenna and an ultra-high frequency band antenna, respectively.

10. The frequency modulation continuous wave radar device as claimed in claim 8, wherein the linear modulation frequency signals of the two incident radar signals are transmitted alternately in a time-division duplex manner.

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