Patent Description:
At present, although there are physiological information detection radars for detecting breathing and heartbeat, in applications such as patient care, long-term care of the elderly, and infant care, the radars are still incapable of detecting the humidity of diapers for the patients, the elderly and infants who need to wear diapers.

<CIT> describes an apparatus, a system, and a method for monitoring the motion, breathing, heart rate and sleep state of subjects, e.g., humans. More particularly, the motion, breathing, and heart rate signals are obtained through processing applied to a raw signal obtained by a radio-frequency sensor. Periods of sleep disturbed respiration, or central apnea can be detected through analysis of the respiratory signal. The mean heart rate, and derived information, such as the presence of cardiac arrhythmias can be determined from the cardiac signal. Motion estimates can be used to recognize disturbed sleep and periodic limb movements. The sleep state may be determined by applying a classifier model to the resulting streams of respiratory, cardiac and motion data.

<CIT> describes a wireless communication device including: a circuit unit; and an antenna which is connected to the circuit unit and which transmits and receives signals to and from a transceiver in a non-contact manner. The wireless communication device transmits different signals to the transceiver, depending on the presence or absence of contact between at least a part of the circuit unit and moisture.

The invention is defined in independent method claims <NUM> to <NUM> and corresponding apparatus claims <NUM>, <NUM> and <NUM>.

According to some embodiments, a method for detecting vital information and humidity includes: transmitting two incident radar signals with different frequencies to a field, and receiving a reflected radar signal corresponding to the field; processing the reflected radar signal to obtain a body reflection signal of an object to be measured and a tag reflection signal of a humidity sensing tag; obtaining vital information according to phase information of the body reflection signal; and obtaining humidity information according to an energy intensity of the tag reflection signal, wherein the body reflection signal is obtained by receiving the incident radar signal with a first frequency and demodulating the reflected radar signal according to the first frequency, and the tag reflection signal is obtained by receiving the incident radar signal with a second frequency and demodulating the reflected radar signal according to the second frequency.

According to some embodiments, a method for detecting vital information and humidity includes: transmitting an incident radar signal to a field and receiving a reflected radar signal corresponding to the field; processing the reflected radar signal to obtain a body reflection signal of an object to be measured and a tag reflection signal of a humidity sensing tag, wherein the humidity sensing tag comprises a frequency multiplication circuit, configured to multiply the frequency of the incident radar signal to generate the reflected radar signal with twice the frequency corresponding to the incident radar signal; obtaining vital information according to phase information of the body reflection signal; and obtaining humidity information according to an energy intensity of the tag reflection signal; wherein the body reflection signal is obtained by demodulating the reflected radar signal according to the frequency corresponding to the incident radar signal, and the tag reflection signal is obtained by demodulating the reflected radar signal according to twice the frequency corresponding to the incident radar signal.

According to some embodiments, a method for detecting vital information and humidity includes: transmitting an incident radar signal to a field and receiving a reflected radar signal corresponding to the field; processing the reflected radar signal to obtain a body reflection signal of an object to be measured and a tag reflection signal of a humidity sensing tag, wherein the humidity sensing tag comprises an input antenna, an oscillator and a frequency mixer coupled between the input antenna and the oscillator, and is configured to generate the reflected radar signal with the same frequency as the incident radar signal, and an oscillation frequency of the oscillator is different than a frequency of vital sign to be measured; obtaining vital information according to phase information of the body reflection signal; and obtaining humidity information according to an energy intensity of the tag reflection signal; wherein the body reflection signal and the tag reflection signal are distinguished according to a phase oscillation frequency of the reflected radar signal.

According to some embodiments, a radio frequency radar device includes: a transmission unit, a receiving unit, a demodulation unit, and a processing unit. The transmission unit is configured to transmit an incident radar signal to a field. The receiving unit is configured to receive a reflected radar signal corresponding to the field. The demodulation unit is coupled to the transmission unit and the receiving unit, and is configured to process the reflected radar signal to obtain a body reflection signal of an object to be measured and a tag reflection signal of a humidity sensing tag. The humidity sensing tag comprises a frequency multiplication circuit, configured to multiply the frequency of the incident radar signal to generate the reflected radar signal with twice the frequency corresponding to the incident radar signal. The processing unit is coupled to the transmission unit, the receiving unit, and the demodulation unit, and is configured to obtain vital information according to phase information of the body reflection signal, and obtain humidity information according to an energy intensity of the tag reflection signal. The body reflection signal (Sb) is obtained by demodulating the reflected radar signal (FN, FN') according to the frequency corresponding to the incident radar signal (FH), and the tag reflection signal (St) is obtained by demodulating the reflected radar signal (FN, FN') according to twice the frequency corresponding to the incident radar signal (FH).

According to some embodiments, a radio frequency radar device includes: a transmission unit, a receiving unit, a demodulation unit, and a processing unit. The transmission unit is configured to transmit an incident radar signal to a field. The receiving unit is configured to receive a reflected radar signal corresponding to the field. The demodulation unit is coupled to the transmission unit and the receiving unit, and is configured to process the reflected radar signal to obtain a body reflection signal of an object to be measured and a tag reflection signal of a humidity sensing tag. The humidity sensing tag comprises an input antenna, an oscillator and a frequency mixer coupled between the input antenna and the oscillator, and is configured to generate the reflected radar signal with the same frequency as the incident radar signal, and an oscillation frequency of the oscillator is different than a frequency of vital sign to be measured. The processing unit is coupled to the transmission unit, the receiving unit, and the demodulation unit, and is configured to obtain vital information according to phase information of the body reflection signal, and obtain humidity information according to an energy intensity of the tag reflection signal. The processing unit distinguishes the body reflection signal and the tag reflection signal according to a phase oscillation frequency of the reflected radar signal.

According to some embodiments, a radio frequency radar device includes a transmission unit, a receiving unit, a first demodulation circuit, a second demodulation circuit, and a processing unit. The transmission unit is configured to transmit two incident radar signals with different frequencies to a field. The receiving unit is configured to receive a reflected radar signal corresponding to the field. The first demodulation circuit is coupled to the transmission unit and the receiving unit, receives the incident radar signal with a first frequency, and is configured to demodulate the reflected radar signal according to the first frequency, to obtain a body reflection signal. The second demodulation circuit is coupled to the transmission unit and the receiving unit, receives the incident radar signal with a second frequency, and is configured to demodulate the reflected radar signal according to the second frequency, to obtain a tag reflection signal. The processing unit is coupled to the transmission unit, the receiving unit, the first demodulation circuit, and the second demodulation circuit, and is configured to obtain vital information according to phase information of the body reflection signal, and obtain humidity information according to an energy intensity of the tag reflection signal.

To sum up, the radio frequency 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, thereby saving device space and hardware cost.

The term "couple" used in this specification means that two or more components are in direct physical or electrical contact with each other, or are in indirect physical or electrical contact with each other.

Referring to <FIG> is a schematic diagram of a use state of a radio frequency radar device <NUM> according to some embodiments. The radio frequency radar device <NUM> 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 radio frequency radar device <NUM> through an object <NUM> to be measured, a humidity sensing tag <NUM>, the environment, and the like. Hereinafter, the radar signal reflected by the object <NUM> to be measured is referred to as "reflected radar signal FN", and the radar signal reflected by the humidity sensing tag <NUM> is referred to as "reflected radar signal FN‴.

In some embodiments, the radio frequency radar device <NUM> is a continuous wave (CW) radar.

Referring to <FIG> and <FIG> together, <FIG> is a schematic architectural diagram of the radio frequency radar device <NUM> according to some embodiments, and <FIG> is a flowchart of a method for detecting vital information and humidity according to some embodiments. The radio frequency radar device <NUM> includes a transceiver <NUM>, a demodulation unit <NUM>, and a processing unit <NUM>. The transceiver <NUM> includes a transmission unit <NUM> and a receiving unit <NUM>. The transmission unit <NUM> is configured to transmit an incident radar signal FH (step S31). The transmission unit <NUM> includes a transmission antenna and an oscillation circuit (not shown). The oscillation circuit may generate a radio frequency signal, and the radio frequency signal is transmitted through the transmission antenna. Therefore, the transmission antenna is designed to be capable of effectively working within a transmission frequency range. Here, the transmission antenna may be a patch antenna, but the disclosure is not limited thereto.

The receiving unit <NUM> is configured to receive the reflected radar signals FN and FN' (step S32). The receiving unit <NUM> includes a receiving antenna, and a working frequency range of the receiving antenna needs to cover the frequencies of the reflected radar signals FN and FN'. Optionally, when the working frequency range of a receiving antenna can cover the frequencies of the reflected radar signals FN and FN', one receiving antenna is available. Conversely, two receiving antennas may be used, and the two receiving antennas separately work in different frequency ranges, so as to cover the frequencies of the reflected radar signals FN and FN' respectively. It can be understood that if only the reflected radar signals FN and FN' with the same frequency are received, there may alternatively be only one receiving antenna.

The demodulation unit <NUM> is coupled to the transmission unit <NUM> and the receiving unit <NUM>, and is configured to process the reflected radar signals FN and FN' to obtain a body reflection signal Sb of the object <NUM> to be measured (step S33) and obtain a tag reflection signal St of the humidity sensing tag <NUM> (step S35). The processing unit <NUM> is coupled to the transmission unit <NUM>, the receiving unit <NUM>, and the demodulation unit <NUM> to control these units, and is configured to obtain vital information according to phase information of the body reflection signal Sb (step S34), and obtain humidity information according to an energy intensity of the tag reflection signal St (step S36). In this way, the vital information and humidity information may be acquired at the same time by the radio frequency radar device <NUM>. For example, if the disclosure is applied to baby care, a vital response and a diaper condition of a baby may be obtained at the same time. However, the invention is not limited to this application.

Before an operation principle of the demodulation unit <NUM> and the processing unit <NUM> is described in detail, an architecture of the humidity sensing tag <NUM> is described first. Referring to <FIG> is a schematic architectural diagram of the humidity sensing tag <NUM> according to a first embodiment. The humidity sensing tag <NUM> includes an input antenna <NUM>, a frequency multiplication circuit <NUM>, an RF-DC converter <NUM>, an oscillator <NUM>, an output antenna <NUM>, and a humidity sensor <NUM>.

The input antenna <NUM> is used for receiving the incident radar signal FH delivered from the radio frequency radar device <NUM>. Here, the input antenna <NUM> may be a dual-dipole patch antenna, but the disclosure is not limited thereto. The input antenna <NUM> is coupled to the frequency multiplication circuit <NUM> and the RF-DC converter <NUM>. The frequency multiplication circuit <NUM> receives the incident radar signal FH received by the input antenna <NUM>, and multiplies the frequency of the incident radar signal FH, that is, generates a signal with a frequency of 2f0 (alternatively, referred to as frequency-multiplied signal) according to the incident radar signal FH with a frequency of f0 (alternatively, referred to as fundamental frequency signal). The RF-DC converter <NUM> is an energy collector, and collects the energy of the incident radar signal FH received by the input antenna <NUM>. A part of the radio frequency signal energy is collected by the RF-DC converter <NUM> and boosted to a working voltage of other circuits, to provide a working voltage of the humidity sensing tag <NUM>. Therefore, the humidity sensing tag <NUM> does not need to be additionally equipped with a battery. However, in some embodiments, the RF-DC converter <NUM> may be replaced by a battery to provide a working voltage of a circuit. The RF-DC converter <NUM> may be mainly implemented by a voltage multiplier composed of a plurality of diodes and a plurality of capacitors. The RF-DC converter <NUM> is also coupled to the oscillator <NUM> to supply a working voltage to the oscillator <NUM>. The oscillator <NUM> is coupled to a bias end of the frequency multiplication circuit <NUM> to generate a specific frequency signal, so as to modulate a signal of the frequency multiplication circuit <NUM>. The specific frequency signal may be identified as a tag. <FIG> exemplifies a composition of the oscillator <NUM>, which may be implemented by components such as inverters G1 and G2, resistors R1 and R2, and a capacitor C1, but the disclosure is not limited thereto.

<FIG> further exemplifies a composition of the frequency multiplication circuit <NUM>, but the disclosure is not limited thereto. The frequency multiplication circuit <NUM> is composed of a diode D1, a plurality of microstrip lines Sp1 to Sp6, a resistor Rbias, and a capacitor C2. An input end of the diode D1 is coupled to components such as the microstrip lines Sp1 and Sp3, the resistor Rbias, and the capacitor C2. The capacitor C2 is used as a bypass capacitor to filter out the frequency-multiplied signal (2f0). The output of the frequency multiplication circuit <NUM> may be started up or stopped by regulating a bias voltage of the diode D1. The resistor Rbias is used as a bias resistor, and is coupled to the oscillator <NUM> to control and modulate the frequency multiplication circuit <NUM>. An output end of the diode D1 is coupled to the microstrip lines Sp2, Sp4, Sp5, and Sp6, and forms a high-pass filter to filter out the fundamental frequency signal (f0). Here, the length of the microstrip line Sp3 is a quarter wavelength of the fundamental frequency signal, and the length of the microstrip lines Sp4, Sp5, and Sp6 is a quarter wavelength of the frequency-multiplied signal.

The output antenna <NUM> is coupled to the frequency multiplication circuit <NUM> to transmit the radio frequency signal that has been modulated and frequency-multiplied, that is, the frequency-multiplied signal (2f0) coupled with the specific frequency signal identified as the tag is output. The output antenna <NUM> is coupled to the humidity sensor <NUM> to form a humidity detection antenna. The humidity sensor <NUM> is a variable capacitor. The change of the medium caused by humidity may affect the dielectric coefficient of the capacitor, which may further affect the resonance frequency of the output antenna <NUM>, causing the energy intensity of the frequency-multiplied signal (2f0) to change. Therefore, the radio frequency radar device <NUM> may know the humidity change by detecting the change of the signal intensity of the frequency-multiplied signal (2f0). The humidity sensor <NUM> may be an interdigital capacitor or a parallel plate capacitor.

Referring to <FIG> is a schematic structural diagram of a humidity detection antenna according to an embodiment. An endpoint <NUM> is a signal feed-in end of the output antenna <NUM>, and receives the signal of the frequency multiplication circuit <NUM>. Here, the output antenna <NUM> is a patch antenna with a length L of <NUM>, a width W of <NUM>, and a feed-in section length Linset of <NUM>. The humidity sensor <NUM> is an interdigital capacitor with <NUM> interdigitated interdigital electrodes. Each electrode has a length of <NUM> and a width of <NUM>, and the electrodes are arranged at intervals of <NUM>. The above specifications are merely examples, and the disclosure is not limited thereto.

Referring to <FIG> is a schematic structural diagram of the humidity sensor <NUM> according to an embodiment. Here, the humidity sensor <NUM> is a parallel plate capacitor having two parallel plates <NUM> and <NUM> spaced up and down.

Referring to <FIG> is a schematic structural diagram of the humidity sensor <NUM> according to another embodiment. Here, the humidity sensor <NUM> is a ring-shaped interdigital capacitor, and includes a ring-shaped upper ring <NUM> and lower ring <NUM> disposed at an interval in a staggered manner.

Referring to <FIG> is a schematic architectural diagram of the radio frequency radar device <NUM> according to the first embodiment. Here, it should be noted that the demodulation unit <NUM> includes a first demodulation circuit <NUM> and a second demodulation circuit <NUM>. The first demodulation circuit <NUM> is configured to demodulate the reflected radar signal FN reflected by the object <NUM> to be measured, and thus the frequency of the reflected radar signal FN is the same as that of the incident radar signal FH, which are f0. The second demodulation circuit <NUM> is configured to demodulate the reflected radar signal FN' backscattered by the humidity sensing tag <NUM>. As described above, the frequency of the reflected radar signal FN' is 2f0. Because the first demodulation circuit <NUM> and the second demodulation circuit <NUM> are separately responsible for demodulating signals with different frequencies, the mutual influence between the body reflection signal Sb and the tag reflection signal St may be avoided.

The first demodulation circuit <NUM> is coupled to the transmission unit <NUM> and the receiving unit <NUM> to receive the incident radar signal FH from the transmission unit <NUM> and demodulate the reflected radar signal FN with the same frequency of f0 according to the frequency (f0) corresponding to the incident radar signal FH, to obtain the body reflection signal Sb. The body reflection signal Sb may reflect the phase information of the phase change caused by body movements of breathing and heartbeat.

The second demodulation circuit <NUM> is coupled to the transmission unit <NUM> and the receiving unit <NUM> to receive the frequency-multiplied incident radar signal FH (2f0) from the transmission unit <NUM>, and is configured to demodulate the reflected radar signal FN' according to twice the frequency (2f0) corresponding to the incident radar signal FH, to obtain the tag reflection signal St. Here, the transmission unit <NUM> includes a frequency multiplier to generate the frequency-multiplied signal 2f0.

The processing unit <NUM> includes a control circuit <NUM>, two analog-to-digital converters <NUM>, and an arithmetic circuit <NUM>. The control circuit <NUM> is coupled to the transmission unit <NUM>, the receiving unit <NUM>, the first demodulation circuit <NUM>, the second demodulation circuit <NUM>, and the arithmetic circuit <NUM>, and is configured to control operation of these components. The two analog-to-digital converters <NUM> are respectively coupled to the first demodulation circuit <NUM> and the second demodulation circuit <NUM> to convert the body reflection signal Sb and the tag reflection signal St into digital signals. The arithmetic circuit <NUM> is coupled to the two analog-to-digital converters <NUM> to perform digital signal processing on the digital signals, such as removing noise, removing high-frequency signals, and removing inappropriate breathing harmonics, so as to calculate breathing and heartbeat information from the body reflection signal Sb. Specifically, vital information such as breathing and heartbeat may be obtained according to the oscillation frequency of the phase information of the body reflection signal Sb, and the respective information types may be distinguished according to their common frequency ranges. On the other hand, the arithmetic circuit <NUM> may determine the energy intensity of the tag reflection signal St, to identify the humidity information of the humidity sensor <NUM>.

Referring to <FIG> is a frequency response diagram of the humidity detection antenna shown in <FIG> under different humidity environments. A suitable resonance frequency in a dry environment is designed to be a working frequency of the tag. It can be seen that in a dry environment, the antenna circuit of the humidity detection antenna is well coordinated, and thus the intensity of the reflected radar signal FN' is high. In a humid environment, the coordination of the antenna circuit of the humidity detection antenna becomes poor, and thus the intensity of the reflected radar signal FN' becomes low. Therefore, the energy intensity of the reflected radar signal FN' may be detected to determine the humidity. In addition, when the humidity reaches a certain level, the reflected radar signal FN' becomes excessively weak, so that the radio frequency radar device <NUM> cannot read the specific frequency used as tag identification, which can also be used as a determination criterion of humidity.

Referring to <FIG> is a schematic diagram of a signal intensity of the tag reflection signal St when the humidity detection antenna shown in <FIG> is under different humidity environments. It can be seen that at different resonance frequencies, the signal intensity may gradually increase or decrease as the humidity increases. For example, the signal intensity gradually decreases at <NUM>, and gradually increases at <NUM>. Therefore, the humidity information may be determined according to a result of comparing the energy intensity of the tag reflection signal St with a threshold, for example, higher than or lower than a certain threshold. The threshold may also be determined in advance by experimentally measuring the change of the working frequency to be used under different humidity conditions.

In some embodiments, because the radio frequency radar device <NUM> and the humidity sensing tag <NUM> also change the energy intensity, the humidity determination may be affected. Therefore, the energy intensity in the dry environment may be recorded first when the diaper is still dry at the beginning, and then the humidity information may be determined according to the result of comparing a variation amount of the energy intensity with a threshold. Alternatively, when the radio frequency radar device <NUM> initially works, the current energy intensity of the reflected radar signal FN' may be recorded first, and when the variation amount of the energy intensity exceeds the threshold, it can be determined that the diaper is wet.

In some embodiments, the frequency f0 in the aforementioned first embodiment is <NUM> to <NUM>, but the disclosure is not limited thereto.

Refer to <FIG> and <FIG> together. <FIG> is a schematic architectural diagram of the radio frequency radar device <NUM> according to a second embodiment. <FIG> is a schematic architectural diagram of a humidity sensing tag <NUM> according to the second embodiment. The difference from the aforementioned first embodiment is that the humidity sensing tag <NUM> of this embodiment does not have the frequency multiplication circuit <NUM>, but has a frequency mixer <NUM> instead, and thus the frequency of the reflected radar signal FN' is the same as that of the reflected radar signal FN and the incident radar signal FH, and all of them have a frequency f0. Therefore, the demodulation unit <NUM> of this embodiment is not divided into the first demodulation circuit <NUM> and the second demodulation circuit <NUM>, but is only a demodulation circuit for demodulating the signal according to the frequency (f0) of the incident radar signal FH to obtain the body reflection signal Sb and the tag reflection signal St. Therefore, the hardware cost may be reduced. In order to avoid mutual influence between the reflected radar signals FN and FN', the oscillation frequency of the oscillator <NUM> should avoid the frequencies of breathing and heartbeat. Therefore, the body reflection signal Sb and the tag reflection signal St may be distinguished according to phase oscillation frequencies of the reflected radar signals FN and FN' (that is, the change frequency of the phase information).

<FIG> is a flowchart of a method for detecting vital information and humidity according to a third embodiment. The radio frequency radar device <NUM> of the aforementioned first embodiment receives two frequency signals, namely f0 and 2f0 respectively, and the radio frequency radar device <NUM> of the second embodiment receives a frequency signal f0. Similarly, the radio frequency radar device <NUM> of the third embodiment receives signals with two different frequencies, but one frequency is not twice the other frequency. In some embodiments, a frequency band used by radars commonly used for measuring vital information, such as <NUM> or <NUM>, may be used as the frequency of the incident radar signal FH for measuring the body reflection signal Sb. Therefore, the detection sensitivity may be improved. On the other hand, the frequency band of <NUM> to <NUM> suitable for the tag is used as the frequency of the incident radar signal FH for measuring the tag reflection signal St. Here, an antenna of the transmission unit <NUM> includes a millimeter-wave antenna (such as an Antipodal Vivaldi antenna) and an ultra-high frequency (UHF) band antenna.

Referring to <FIG>, in step S41, two incident radar signals FH with different frequencies are transmitted to the field. Next, in step S42, the reflected radar signals FN and FN' corresponding to the field are received. Subsequently, the reflected radar signal FN is demodulated according to a frequency of one of the incident radar signals FH to obtain the body reflection signal Sb (step S43), and the vital information is obtained according to the phase information of the body reflection signal Sb (step S44). On the other hand, the reflected radar signal FN' is demodulated according to the frequency of the other incident radar signal FH to obtain the tag reflection signal St (step S45), and the humidity information is obtained according to the energy intensity of the tag reflection signal St (step S46).

Referring to <FIG> is a schematic diagram of time-division multi-tasking according to some embodiments. The two incident radar signals FH in the third embodiment may be transmitted in a time-division duplex manner. In a first mode, the incident radar signal FH for measuring the body reflection signal Sb is transmitted, and in a second mode, the incident radar signal FH for measuring the tag reflection signal St is transmitted.

In some embodiments, the control circuit <NUM>, the two analog-to-digital converters <NUM>, and the arithmetic circuit <NUM> may be independent or be integrated together, and may be components such as a processor, a microprocessor, and a system-on-chip.

Claim 1:
A method for detecting vital information and humidity, wherein the method for detecting vital information and humidity comprises:
transmitting two incident radar signals (FH) with different frequencies to a field and receiving a reflected radar signal (FN, FN') corresponding to the field;
processing the reflected radar signal (FN, FN') to obtain a body reflection signal (Sb) of an object (<NUM>) to be measured and a tag reflection signal (St) of a humidity sensing tag (<NUM>);
wherein the body reflection signal is obtained by receiving the incident radar signal with a first frequency and demodulating the reflected radar signal according to the first frequency, and the tag reflection signal is obtained by receiving the incident radar signal with a second frequency and demodulating the reflected radar signal according to the second frequency,
obtaining vital information according to phase information of the body reflection signal (Sb); and
obtaining humidity information according to an energy intensity of the tag reflection signal (St).