TWI627431B - Frequency modulated continuous wave detector and detecting method thereof - Google Patents

Abstract

The present disclosure provides an FM continuous wave detector and a detection method thereof. The FM continuous wave detector comprises: an antenna module for transmitting an FM continuous wave signal and receiving the reflected echo signal; and an RF module connected to the antenna module for generating the frequency modulation continuous The signal module includes a phase shift controller for generating a phase offset signal according to the echo signal, and the phase shifter controls the phase of the echo signal at a quarter wavelength (90 degrees) Internal offset, obtaining the maximum amplitude value of the standing wave formed by the frequency modulated continuous wave signal and the echo signal (ie, capturing the peak position and avoiding the valley position); and an analog/digital controller for The integral curve of the maximum amplitude signal of the echo determines whether there is a target.

Description

Frequency modulated continuous wave detector and detection method thereof

The present disclosure relates to an FM continuous wave detector, and more particularly to a frequency modulated continuous wave detector for detecting a close range stationary object.

Microwave vehicle detectors are often designed using the concept of radar. The main principle of the FM continuous wave radar is to transmit a set of electromagnetic waves whose frequency changes with time by frequency modulation, and then use the frequency difference between the radar wave and the radar echo to judge the presence or absence of the target, and calculate The relative distance between the target and the detector.

When a conventional FM continuous wave detector detects a close-range stationary object, the target is detected by a first beat frequency. However, in the first beat frequency, although the reflected echo signal is large, the standing wave phenomenon is very obvious and the coupling between near-field interference and RF transmission and reception is also obvious. A standing wave or a stationary wave is a composite wave in which two sinusoidal waves of the same wavelength, period, frequency, and wave velocity are reversely traveled. Unlike the Traveling wave, the waveform of the standing wave cannot advance, so energy cannot be transmitted. The standing wave problem will cause the position of the target and the relative distance of the detector to be exactly at the trough position of the composite wave. At this time, the echo signal is destructive interference, and even the echo signal will be smaller than the system noise level. The detector cannot measure the signal of its echo. Therefore, the conventional FM continuous wave detector is not suitable It is used to detect stationary objects at close range.

Furthermore, in FM continuous wave detectors, the isolation of the transmitting and receiving antennas is the biggest factor affecting the receiving sensitivity. The isolation of the transmitting end and the receiving end of the conventional RF transceiver of the FM continuous wave detector is only about 25 dB. In theory, the architecture of a dual antenna that receives a transmission can make the isolation between the transmitter and the receiver greater than 35 dB. However, it has been confirmed through actual test results that since part of the energy radiated by the transmitting antenna is coupled and received by the adjacent receiving antenna, the isolation between the transmitting end and the receiving end is still less than 30 dB even with the dual antenna architecture. Specifically, when the radar signal is down-converted to the intermediate frequency signal, the system noise level will become higher without the target. If the problem is combined with the standing wave phenomenon, the difficulty of the close distance measurement will be increased.

In view of this, it is necessary to propose an improved frequency modulated continuous wave detector to solve the problems in the prior art.

In order to solve the above problems of the prior art, the purpose of the present disclosure is to provide a frequency modulated continuous wave detector and a detection method thereof. By changing the phase of the received echo signal, the peak value and the trough value of the standing wave formed by the frequency modulated continuous wave signal and the echo signal are obtained, and the integral curve of the maximum amplitude signal can be used to determine whether there is a static at a close distance. Target.

To achieve the above objective, the present disclosure provides an FM continuous wave detector, comprising: an RF module for generating a frequency modulated continuous wave signal; and an antenna module for emitting a frequency modulated continuous wave signal and receiving the reflected back An RF module connected to the antenna module for generating the frequency modulated continuous wave signal, the RF module comprising: a receiver for receiving the echo signal; and a phase shift controller And connecting to the receiver, configured to generate a phase offset signal according to the echo signal, wherein the echo signal and the phase offset signal have no The phase difference is controlled by the phase shifter to shift the phase of the echo signal within a quarter wavelength (90 degrees) to obtain the maximum standing wave formed by the frequency modulated continuous wave signal and the echo signal. The amplitude value (ie, the position of the captured peak and the position of the avoiding trough); and an analog/digital controller for determining whether there is a target based on the integral curve of the maximum amplitude signal of the echo.

In a preferred embodiment of the present disclosure, the analog/digital controller includes: an intermediate frequency module for converting the echo signal into an intermediate frequency signal; and a signal processing module for respectively Converting the peak value and the trough value to a high level value and a low level value, and when the IF signal is greater than the high level value or when the IF signal is less than the low level value, and may be the maximum amplitude The integration curve of the signal, the signal processing module determines that the target exists.

In a preferred embodiment of the present disclosure, the signal processing module includes: an integration circuit for obtaining a standard reference level for environmental signal integration generated without the target, and The peak of the wave is integrated with the valley value to obtain an offset, so that the signal processing module combines the standard reference level with the offset of the wave peak and the valley value to generate the high level value and the a low level value; and a comparison circuit coupled to the integration circuit for comparing the magnitude of the intermediate frequency signal with the high level value and the low level value, and determining an integral curve of the maximum amplitude signal to determine whether the target exists Things.

In a preferred embodiment of the present disclosure, the phase shift controller further includes: a delay circuit for delaying the echo signal to generate the phase offset signal; and an encoding control circuit for controlling the The delay circuit is turned on or off to determine whether the echo signal passes through the delay circuit.

In a preferred embodiment of the present disclosure, the echo signal and the phase shift signal have a phase difference greater than 0 degrees and less than or equal to 90 degrees.

In a preferred embodiment of the present disclosure, the antenna module includes a pair of receiving antenna arrays arranged orthogonally to each other.

The present disclosure further provides a method for detecting a frequency modulated continuous wave detector, comprising: generating a frequency modulated continuous wave signal by using a radio frequency module; and transmitting the reflected echo signal by a group of external frequency signals; and receiving the reflected echo Receiving the echo signal by one of the RF module receivers; and generating a phase offset signal by the phase shift controller of the RF module, the phase shift signal and the echo signal having a phase difference; the phase shift controller takes the maximum value between the echo signal and the phase offset signal as the maximum amplitude of the standing wave formed by the frequency modulated continuous wave signal and the echo signal, and then obtains The peak value and the trough value of the standing wave; and an analog/digital controller according to the peak value and the trough value, and the integral curve of the maximum amplitude signal can determine whether there is a target.

In a preferred embodiment of the present disclosure, the step of determining, by the analog/digital controller, whether a target exists based on the peak value and the valley value comprises: the echo signal by an intermediate frequency module Converting to an intermediate frequency signal; and converting the peak value and the valley value to a high level value and a low level value by a signal processing module; and comparing the medium frequency signal with the high level value and the low level The magnitude of the quasi value, wherein the signal processing module determines that the target exists when the intermediate frequency signal is greater than the high level value or when the intermediate frequency signal is less than the low level value.

In a preferred embodiment of the present disclosure, the step of converting the peak value and the trough value into a high level value and a low level value by a signal processing module includes: using the radio frequency module Generating an environmental signal without the target; integrating the environmental signal by an integrating circuit to obtain a standard reference level, and the peak value and the trough value An offset is obtained by integrating, so that the signal processing module combines the standard reference level with the offset of the peak value and the valley value to generate an integral curve of the high level value and the low level value.

In a preferred embodiment of the present disclosure, the step of generating a phase offset signal by using a phase shift controller of the radio frequency module includes: providing at least one delay circuit; providing an encoding control circuit; And the input signal received by the encoding control circuit controls whether the delay circuit is turned on or off to determine whether the echo signal passes through the delay circuit, wherein the phase shift signal is generated when the echo signal passes through the delay circuit.

In a preferred embodiment of the present disclosure, the antenna module includes a pair of receiving antenna arrays arranged orthogonally to each other, and one of the analog/digital controllers, the signal processing module compares the pair of receiving antenna arrays The strength of the received signal, and the stronger signal is used as the echo signal.

Compared with the prior art, the present disclosure provides a phase shift controller in a frequency modulated continuous wave detector for changing the phase of the received echo signal, thereby obtaining a station formed by the frequency modulated continuous wave signal and the echo signal. The wave peak and trough value of the wave. Moreover, the analog/digital controller obtains a high level value and a low level value based on the peak value and the valley value, and uses it as the upper and lower limit values of the signal trigger, thereby effectively determining whether there is a stationary target at a close distance. Things.

1‧‧‧FM continuous wave detector

10‧‧‧RF Module

11‧‧‧Transmitter

12‧‧‧ Receiver

13‧‧‧ Phase Offset Controller

20‧‧‧Antenna Module

21‧‧‧First transmit antenna array

22‧‧‧First Receive Antenna Array

23‧‧‧Second transmit antenna array

24‧‧‧Second receiving antenna array

30‧‧‧ Analog/Digital Controller

31‧‧‧Down Frequency Module

32‧‧‧Signal Processing Module

321‧‧‧Integral circuit

322‧‧‧Comparative circuit

33‧‧‧Signal generation module

2‧‧‧Upper cover

Tx‧‧‧FM continuous wave signal

Rx‧‧‧ echo signal

VCO‧‧‧voltage controlled oscillator

P‧‧‧Receiving path

A‧‧‧First delay circuit

B‧‧‧second delay circuit

C‧‧‧third delay circuit

Pin‧‧‧ Receiver

Pout‧‧‧ output

IN1‧‧‧ first input

IN2‧‧‧ second input

V0‧‧‧ standard reference level

V1‧‧‧ high level

V2‧‧‧ low level

G‧‧‧ trigger signal

M‧‧‧ IF signal

H‧‧‧ distance

S10~S60‧‧‧Steps

1 is a block diagram of a frequency modulated continuous wave detector in accordance with a preferred embodiment of the present disclosure; and FIG. 2 is a diagram showing a frequency modulated continuous wave detector detecting unit in accordance with a preferred embodiment of the present disclosure. Figure 3 shows a schematic diagram of the antenna module of Figure 1; Figure 4 shows the output relationship of the receiver's receive path and the phase offset controller's delay circuit of Figure 1; Figure 5 shows FIG. 1 is a schematic diagram of an encoding control circuit of a phase shift controller of FIG. 1; FIG. 6 is a schematic diagram showing the use of the FM continuous wave detector of FIG. 1 for testing a target at a close distance; FIG. 7 is a view of FIG. A schematic diagram of the signal processing module; and FIG. 8 shows a waveform diagram of the detection signal of the FM continuous wave detector of FIG.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

Referring to FIG. 1, a block diagram of a frequency modulated continuous wave detector 1 in accordance with a preferred embodiment of the present disclosure is shown. The FM continuous wave detector 1 includes a radio frequency module 10, an antenna module 20, and an analog/digital controller 30. The radio frequency module 10 includes a transmitter 11, a receiver 12, and a phase shift controller 13. The analog/digital controller 30 includes a down-conversion module 31, a signal processing module 32, and a signal generation module 33. The RF module 10 is connected to the receiver 12 and the antenna module 20 by the transmitter 11, and the RF module 10 is connected to the analog/digital controller 30. The FM continuous wave detector 1 of the present disclosure is suitable for detecting a stationary object at a close distance, for example, as a parking lot sensor for detecting whether a vehicle is parked, and the detection method is as follows.

Please refer to FIG. 1 and FIG. 2 . FIG. 2 is a flow chart showing a method for detecting a frequency modulated continuous wave detector according to a preferred embodiment of the present disclosure. Frequency modulated continuous wave detector of the present disclosure The detection method is implemented by the frequency modulated continuous wave detector 1. First, step S10 is performed to generate a frequency modulated continuous wave signal by the radio frequency module 10. Specifically, when the FM continuous wave detector 1 is activated, the signal generation module 33 of the analog/digital controller 30 generates a low frequency triangular wave, which is controlled by the voltage controlled oscillator VCO, and the frequency is controlled. The frequency modulation module 10 can generate the frequency modulated continuous wave signal, and the frequency modulated continuous wave signal is transmitted to the antenna module 20 by the transmitter 11.

It should be noted that the FM continuous wave detector 1 is preferably designed using the ISM band. If the frequency band of 10 GHz is used, only the bandwidth of 50 MHz has a minimum resolution of 3 meters and the size of the antenna used is large, so it is not suitable for close-range detection such as parking. Therefore, the FM continuous wave detector 1 of the present disclosure preferably has a frequency band of 24 GHz with a bandwidth of 250 MHz. Considering the range of movement of the center frequency, with a bandwidth of 200 MHz as the emission bandwidth, the minimum range of resolution is 0.75 meters, and the size of the formed antenna is also small. Therefore, the FM continuous wave detector 1 of the present disclosure can be used for close-range detection such as parking.

After the frequency modulated continuous wave signal is generated by the radio frequency module 10, step S20 is performed to send the frequency modulated continuous wave signal Tx to the outside through the antenna module 20, and receive the reflected echo signal Rx. It should be noted that in the FM continuous wave detector 1, the isolation of the transmitting and receiving antennas is the largest factor affecting the receiving sensitivity. When the isolation between the transmitting end and the receiving end is less than 30 dB, part of the energy radiated by the transmitting antenna is coupled and received by the adjacent receiving antenna, so that the system noise level becomes higher without the target, thereby increasing the close distance measurement. The difficulty. Accordingly, the antenna module 20 of the present disclosure is designed to include a pair of receive antenna arrays that are orthogonally arranged to each other.

Referring to Figure 3, there is shown a schematic diagram of the antenna module 20 of Figure 1. Antenna module 20 includes a first transmit antenna array 21, a first receive antenna array 22, a second transmit antenna array 23, and a second receive antenna array 24, wherein the first transmit antenna array 21 and the first receive antenna array 22 are integrated on the same wafer And the second transmit antenna array 23 and the second receive antenna array 24 are integrated on another wafer. As shown in FIG. 3, the first receiving antenna array 22 and the second receiving antenna array 24 are orthogonally arranged to each other, and the first receiving antenna array 22 and the second receiving antenna array 24 are both linearly polarized antennas. Therefore, by the structure arranged orthogonally to each other, the coupling interference between the transmitting end and the receiving end of the antenna module 20 can be minimized, and the phase difference of the receiving end can also compensate each other, so that the isolation between the antennas can be maintained above 35 dB. . Secondly, during the measurement, the signal processing module 32 of the analog/digital controller 30 compares the strength of the signals received by both the first receiving antenna array 22 and the second receiving antenna array 24, and uses the stronger signal as the stronger signal. Echo signal Rx. It is to be understood that, in other embodiments, a design in which a set of transmit antenna arrays and two sets of receive antenna arrays are integrated on the same wafer may be employed, and is not limited thereto.

After receiving the reflected echo signal Rx, the antenna module 20 then proceeds to step S30 to receive the echo signal Rx by the receiver 12 of the radio frequency module 10. Next, in step S40, the phase offset controller 13 of the radio frequency module 10 changes the length of the receiving path of the receiver 12 to generate a phase offset signal according to the echo signal Rx. The receiving path of the receiver 12 is connected to the phase shift controller 13, and the method of changing the length of the receiving path of the receiver 12 is detailed below.

Referring to FIG. 4, FIG. 4 is a diagram showing the relationship between the reception path of the receiver 12 of FIG. 1 and the output of the delay circuit of the phase shift controller 13. The receiver 12 includes a reception path P, and the phase shift controller 13 includes a first delay circuit A, a second delay circuit B, and a third delay circuit C that are switchably connected to the reception path P. The first delay circuit A, the second delay circuit B, and the third delay circuit C are used to delay the echo signal Rx to generate a corresponding phase offset signal. For example, when The received echo signal Rx is input to the receiving end Pin of the receiver 12, and after passing through the receiving path P which is not connected to any of the delay circuits A, B, C, the output terminal Pout outputs a signal having the same phase as the original input, that is, Echo signal Rx. In another case, when the receiving path P is connected to the first delay circuit A, the receiver 12 outputs a first phase offset signal, wherein the first phase offset signal and the echo signal Rx have a phase of 30 degrees. difference. In another case, when the receiving path P is connected to the second delay circuit B, the receiver 12 outputs a second phase offset signal, wherein the second phase offset signal and the echo signal Rx have a phase of 60 degrees. difference. In another case, when the receiving path P is connected to the third delay circuit C, the receiver 12 outputs a third phase offset signal, wherein the third phase offset signal and the echo signal Rx have a phase of 90 degrees. difference.

It can be understood that the phase shift controller 13 can be implemented by a microstrip circuit or a radio frequency integrated circuit (RFIC). The following uses an RFIC as an example for explanation. Please refer to FIG. 5, which shows a schematic diagram of the encoding control circuit of the phase shift controller 13 of FIG. In the present embodiment, the encoding control circuit is implemented using a two-bit encoding control circuit, but the present disclosure is not limited thereto. The binary encoding control circuit operates together with the first delay circuit A, the second delay circuit B, and the third delay circuit C described above. The binary encoding control circuit includes a first input terminal IN1 and a second input terminal IN2. The two-bit encoding control circuit can be presented in a digital or analog circuit alone, or integrated into the RFIC to implement the circuit (as shown in Figure 5). The two-bit code control circuit controls the input signals of the first input terminal IN1 and the second input terminal IN2 by two bits, thereby controlling the first delay circuit A, the second delay circuit B, and the third delay circuit C. The signal is connected or disconnected, so that the RF module 10 outputs signals of four different phase angles, that is, the echo signal Rx, the first phase offset signal, the second phase offset signal, and the third phase offset signal.

For example, when both the first input terminal IN1 and the second input terminal IN2 input an input signal of “0”, the first delay circuit A, the second delay circuit B, and the third delay circuit C are not connected to the receiving path P. Therefore, the output terminal Pout of the receiver 12 outputs a signal with a phase difference of 0, that is, an echo signal Rx. In another case, when the first input terminal IN1 inputs the input signal of "1" and the input signal of the second input terminal IN2 inputs "0", the receiving path P is connected with the first delay circuit A, so that the receiver 12 The output terminal Pout outputs a first phase shift signal having a phase difference of 30 degrees. In another case, when the first input terminal IN1 inputs the input signal of "0" and the input signal of the second input terminal IN2 inputs "1", the receiving path P is connected with the second delay circuit B, so that the receiver 12 The output terminal Pout outputs a second phase shift signal having a phase difference of 60 degrees. In another case, when both the first input terminal IN1 and the second input terminal IN2 input an input signal of "1", the receiving path P is connected to the third delay circuit C, so that the output terminal Pout of the receiver 12 outputs A third phase shift signal having a phase difference of 90 degrees.

It will be appreciated that the phase offset controller 13 also includes a path selection circuit. The path selection circuit is connected between the delay circuits A, B, C and the reception path P of the receiver 12 for switching the conduction or disconnection between the delay circuits A, B, C and the reception path P of the receiver 12. Preferably, the path selection circuit includes a diode having a switching function, which causes a current to flow by turning a voltage in the forward direction to turn on the circuit, or a reverse voltage application to stop the flow of the current to disconnect the circuit.

It should be noted that in the present embodiment, the phase difference between the echo signal Rx and the first, second, and third phase shift signals is 30 degrees. However, in other embodiments, the phase difference between the echo signal Rx and the first, second, and third phase offset signals may also be selected to be greater than 0 degrees and less than or equal to 90 degrees to obtain different phases and different numbers of phase offsets. The mobile number.

Again, it should be noted that the phase shift controller 13 can only be connected to the receiver 12 and not to the transmitter 11. Referring to Fig. 6, there is shown a schematic diagram of the FM continuous wave detector 1 of Fig. 1 for testing a target that is stationary at a short distance. In use, the FM continuous wave detector 1 is placed in the casing, and the FM continuous wave detector 1 must be separated from the upper cover 2 by a specific distance H. Preferably, the distance H must be greater than the electromagnetic near field range of the FM continuous wave detector 1. And the frequency modulated continuous wave signal Tx of the frequency modulated continuous wave detector 1 is transmitted to the distance H at a position substantially equal to the trough position of the waveform, so that the reflection of the signal is minimized. Therefore, if the phase of the frequency-modulated continuous wave signal Tx of the output is changed, the position of the trough of the signal is affected, so that the error of the measurement result is caused by the reflection of the upper cover 2.

After the different phase offset signals are generated, step S50 is performed to obtain the frequency modulated continuous wave signal Tx and the echo signal Rx according to the echo signals and the sizes of the first, second, and third phase offset signals. The maximum amplitude, peak value and trough value of the standing wave. Specifically, the peak value and the trough value of the standing wave are taken, and the maximum value is obtained as the maximum amplitude of the standing wave.

Next, in step S60, the analog/digital controller 30 determines whether or not the target exists based on the peak value and the trough value. Specifically, please refer to FIG. 7 and FIG. 8. FIG. 7 shows a schematic diagram of the signal processing module 32 of FIG. 1 and FIG. 8 shows the detection signal of the FM continuous wave detector of FIG. Waveform diagram. The signal processing module 32 of the analog/digital controller 30 includes an integration circuit 321 and a comparison circuit 322. The signal processing module 32 integrates the environmental signals generated without the target by the integration circuit 321 to establish a standard reference level V0. In addition, the integration circuit 321 integrates the peak value with the valley value to obtain an offset, and the signal processing module 32 combines the standard reference level V0 with the offset of the wave peak and the valley value. Production The integral curve of the high level value V1 and the integral curve of the low level value V2. After receiving the echo signal Rx, the analog/digital controller 30 converts the echo signal Rx into the intermediate frequency signal M by the frequency reduction module 31, that is, the standing wave formed by the frequency modulated continuous wave signal Tx and the echo signal Rx. The integral curve of the maximum amplitude signal. The signal processing module 32 of the analog/digital controller 30 compares the integral curve of the intermediate frequency signal M with the integral curve of the high level value V1 and the integral curve of the low level value V2, and the integral curve and the low level of the high level value V1. The integral curve of the value V2 is used as the upper and lower limits of the signal trigger. When the integral curve of the intermediate frequency signal M is greater than the integral curve of the high level value V1 or the integral curve of the intermediate frequency signal M is smaller than the integral curve of the low level value V2 (such as the trigger signal G of FIG. 8), the signal processing module 32 determines There are stationary targets at close range.

It can be understood that the signal processing module 32 can be implemented by using an intermediate frequency analog circuit or a digital signal processor (DSP). When an IF analog circuit is used, the standard reference level V0 is established in a standard environment such as a laboratory. In addition, when the digital signal processing unit is used, the standard reference level V0 is generated by self-learning to read the integral value of the environmental reflection signal after being installed at a test location (such as a parking lot) and after initial power-on. Preferably, the present disclosure uses a digital signal processing unit as the signal processing module 32.

In summary, the present disclosure provides a phase shift controller in an FM continuous wave detector for changing the phase of the received echo signal, thereby obtaining a standing wave formed by the frequency modulated continuous wave signal and the echo signal. The peak value of the wave and the valley value are obtained as the maximum amplitude of the standing wave. Moreover, the analog/digital controller obtains a high level value and a low level value based on the peak value and the valley value, and uses it as the upper and lower limit values of the signal trigger, thereby effectively determining whether there is a stationary target at a close distance. Things. Furthermore, by providing a pair of receiving antenna arrays arranged orthogonally to each other, the isolation between the antennas can be maintained above 35 dB. Digital signal The processing unit is used as a signal processing module to achieve self-learning to read the environmental reflection signal and thereby generate a standard reference level.

The above is only a preferred embodiment of the present disclosure, and it should be noted that those skilled in the art can also make several improvements and refinements without departing from the principles of the present disclosure. These improvements and refinements should also be considered as protected range.

Claims (11)

An FM continuous wave detector includes: an antenna module for transmitting an FM continuous wave signal and receiving a reflected echo signal; and an RF module coupled to the antenna module for generating the frequency modulation a continuous wave signal, the RF module includes: a receiver for receiving the echo signal; and a phase shift controller coupled to the receiver for generating a phase offset signal according to the echo signal, The echo signal has a different phase difference from the phase offset signal, and the phase offset controller takes the maximum value between the echo signal and the phase offset signal as the frequency modulated continuous wave signal and the echo signal. a peak value and a trough value of the standing wave formed to obtain a maximum amplitude of the standing wave; and an analog/digital controller connected to the radio frequency module for determining whether there is a peak according to the peak value and the trough value Target. The frequency modulation continuous wave detector according to claim 1, wherein the analog/digital controller comprises: an intermediate frequency module for converting the echo signal into an intermediate frequency signal; and a signal processing a module, configured to respectively convert the peak value and the trough value into a high level value and a low level value, and when the intermediate frequency signal is greater than the high level value or when the intermediate frequency signal is less than the low level value The signal processing module determines that the target exists. The frequency modulation continuous wave detector according to claim 2, wherein the signal processing module comprises: An integrating circuit for obtaining a standard reference level by integrating the environmental signal generated without the target, and integrating the peak value with the valley value to obtain an offset, so that the signal processing The module combines the standard reference level with the respective offset of the peak value and the valley value to generate the high level value and the low level value; and a comparison circuit coupled to the integrating circuit for comparing the The intermediate frequency signal and the high level value and the low level value are used to determine whether the target object exists. The frequency modulation continuous wave detector according to claim 1, wherein the phase shift controller further comprises: a delay circuit for delaying the echo signal to generate the phase offset signal; and an encoding control a circuit for controlling whether the delay circuit is turned on or off to determine whether the echo signal passes through the delay circuit. The frequency modulated continuous wave detector of claim 1, wherein the echo signal and the phase offset signal have a phase difference greater than 0 degrees and less than or equal to 90 degrees. The frequency modulated continuous wave detector of claim 1, wherein the antenna module comprises a pair of receiving antenna arrays arranged orthogonally to each other. A method for detecting a frequency modulated continuous wave detector includes: generating a frequency modulated continuous wave signal by an RF module; transmitting the frequency modulated continuous wave signal by an antenna module, and receiving the reflected echo signal; The receiver of the RF module receives the echo signal; and the phase shift controller of the RF module generates a phase offset signal, and the phase offset signal has a phase difference from the echo signal; And obtaining, by the phase shift controller, the maximum value between the echo signal and the phase offset signal as a peak value and a valley value of the standing wave formed by the frequency modulated continuous wave signal and the echo signal, thereby acquiring the The maximum amplitude of the standing wave; and determining whether there is a target based on the peak value and the valley value by a class/digital controller. The method for detecting a frequency modulated continuous wave detector according to claim 7, wherein the step of determining whether a target exists by the peak value and the valley value by the analog/digital controller comprises: An IF module converts the echo signal into an intermediate frequency signal; the signal processing module respectively converts the peak value and the valley value into a high level value and a low level value; and compares the intermediate frequency The signal and the high level value and the low level value, wherein the signal processing module determines that the target exists when the intermediate frequency signal is greater than the high level value or when the intermediate frequency signal is less than the low level value . The method for detecting a frequency modulated continuous wave detector according to claim 8, wherein the peak value and the valley value are respectively converted into a high level value and a low level value by a signal processing module. The step of: generating, by the RF module, an environmental signal without the target; and integrating the environmental signal by an integrating circuit to obtain a standard reference level, and the peak value and the trough The value is integrated to obtain an offset such that the signal processing module combines the standard reference level with the respective offset of the peak value and the valley value to generate the high level value and the low level value. The method for detecting a frequency modulated continuous wave detector according to claim 7, wherein the step of generating a phase offset signal by one of the phase shift controllers of the radio frequency module comprises: providing at least one delay And providing an encoding control circuit, wherein the input signal received by the encoding control circuit controls the delay circuit to be turned on or off to determine whether the echo signal passes through the delay circuit, wherein the echo signal passes through the delay circuit The phase shift signal is generated. The method for detecting a frequency modulated continuous wave detector according to claim 7, wherein the antenna module comprises a pair of receiving antenna arrays arranged orthogonally to each other, and one of the analog/digital controllers The group compares the strength of the signal received by the pair of receiving antenna arrays and uses the stronger signal as the echo signal.