CN113176450A - Near-field microwave sensing signal processing device and method using microwave radar chipset - Google Patents
Near-field microwave sensing signal processing device and method using microwave radar chipset Download PDFInfo
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Abstract
A near-field microwave sensing signal processing device and method using a microwave radar chipset. The device includes: a radar chip set mounted on a single printed circuit board, configured to generate a desired waveform, transmit and receive microwave signals, quadrature mix to obtain an intermediate frequency signal, filter, amplify, digitize the intermediate frequency signal; the microwave transmitting probe transmits microwave signals in the near field of a target area of a measured object, and the microwave detecting probe receives reflected or transmitted near field microwave signals; the sensor circuit processes the microwave signal output by the radar chip set and inputs the microwave signal into the sensor probe, and the near-field microwave signal received by the sensor probe is input into the radar chip set; the processor system manages the radar chip set, controls the measuring process, and calculates the absolute position or dielectric property of the target area of the measured object from the intermediate frequency signal and the position of the sensor probe. The near-field microwave sensing application of the microwave radar chipset is realized, and the sensing signal processing device has the advantages of higher integration level, lower power consumption, lighter weight and higher cost performance.
Description
Technical Field
The present invention relates generally to electronic systems and methods, and in particular embodiments, to near-field microwave detection using a microwave radar chipset.
Background
Microwave radars are widely used in the fields of automobiles, industry, and the like to reliably detect the presence, movement, direction, distance, speed, and the like of a target object. Microwave radars have unique advantages over ultrasonic, infrared or laser based sensors. For example, the influence of environmental humidity, dust, temperature and the like on the test result can be further reduced.
Microwave radar chip sets are used to implement multi-channel radar systems on small printed circuit boards. The microwave radar chip group integrates a plurality of microwave generating, transmitting and receiving corresponding whole microwave transceiving modules and a baseband analog circuit module by using a semiconductor process. The microwave transceiver module comprises a low-phase noise microwave signal source, a power amplifier, a low-noise amplifier, a multiplier and the like. The baseband analog circuit module includes an Intermediate Frequency (IF) filter, an analog-to-digital conversion, and the like. Further, the microwave radar chipset may integrate a Digital Signal Processor (DSP) or a Micro Controller Unit (MCU), etc. to provide various storage interfaces or system peripheral interfaces, etc. The system peripheral interface includes: the device comprises a serial low-voltage differential signaling interface (LVDS) for debugging data, an inter-integrated circuit interface (I2C), a Serial Peripheral Interface (SPI), a universal serial bus interface (UART), a general input/output port (GPIO), a CAN bus interface, a CAN-FD bus interface, a USB interface and the like.
The operating frequency of the mainstream microwave radar chipset is around 24GHz, 60GHz or 77 GHz. These mass-produced radar chips need to be certified by the stringent AEC-Q100 reliability standard and the automotive functional safety standard ISO 26262 third party agency.
In the application of the fields of traditional automobiles, industry and the like, the microwave radar chip set is externally connected with an antenna module, a detected object is positioned in a far field of an antenna, and the detection working range is far larger than the wavelength of a detected microwave signal. The sensing measurement principle of the far-field microwave radar is as follows: the electromagnetic wave propagates at the speed of light, and the distance between a target object and a radar sensor determines the time difference between the transmission and the reception of a microwave signal, so that the frequency difference between the reflected microwave and the transmitted microwave is further caused; the target object moves relative to the radar sensor to generate Doppler frequency shift; a plurality of microwave receiving ports (Rx) are used to receive microwaves reflected by the same target object, different receiving ports have different time differences of transmitted and reflected signals, and angle information of the target object is calculated by evaluating the phase differences among the plurality of receiving ports. A microwave waveform generator integrated with a microwave radar chip set generates a microwave Continuous Wave (CW) or a Frequency Modulated Continuous Wave (FMCW) or a Frequency Shift Keying (FSK) signal or other more complex modulation signals; after power amplification, transmitting microwaves through a microwave transmitting port (Tx) and an external antenna module; reflecting microwaves by a target object to return to a microwave receiving port (Rx), amplifying the microwaves with low noise, and mixing a local oscillator and the reflected microwaves to generate an Intermediate Frequency (IF) signal; filtering and analog-to-digital converting the intermediate frequency signal; and performing Fast Fourier Transform (FFT) on the digitized signal to determine information such as the position, the speed, the angle and the like of the detection target. The microwave radar can adopt a multi-channel structure, and a multi-channel input multi-channel output (MIMO) radar architecture can complete more complex and accurate measurement work.
The near-field microwave sensing device at least comprises a position adjusting device and a near-field microwave sensing signal processing device. The position adjusting device adjusts the microwave transmitting probe to be in a near field range of a target area of the measured object, the microwave signal irradiates the target area of the measured object through the sensor probe, and the near field microwave signal has the absolute position of the target area of the measured object and dielectric property information of the target area of the measured object. High quality factor microwave resonators are used to improve the signal-to-noise ratio of near field microwave sensing. In near-field microwave measurement, the distance between the sensor probe and the target area of the measured object can be far less than the wavelength of the detected microwave signal. The absolute position precision of the near-field microwave sensing device can be smaller than microns and far smaller than the wavelength of a detected microwave signal. Furthermore, the near-field microwave sensing device can quantitatively test the dielectric property of the target area of the measured object without contact and damage. The dielectric properties are related to factors such as material and temperature.
Disclosure of Invention
Near-field microwave sensing systems are typically implemented using discrete solutions that are large in size, complex, and costly to build, which limits their potential widespread industrial use. The microwave radar chipset is externally connected with a far-field antenna to realize an ultra-low power consumption multi-channel radar system on a small-sized printed circuit board. The radar chip set has the advantages of low system noise, large dynamic range, wide frequency range, high frequency resolution, quick frequency conversion, quick frequency modulation continuous wave providing and the like, and is suitable for providing amplitude and phase information of near-field microwave signals of a target area of a measured object for the near-field microwave sensing signal processing device after optimized design.
The invention uses the microwave radar chip group, especially the millimeter wave radar chip group technology for near field microwave signal processing, the near field microwave sensing signal processing device is more compact, and the near field microwave sensing embedded application or palm application can be realized.
The technical scheme of the invention is as follows:
a near-field microwave sensing signal processing apparatus, comprising: radar chip group, sensor probe, sensor circuit. A radar chipset configured to generate a desired waveform, transmit and receive microwave signals, mix to obtain an intermediate frequency signal, filter, amplify, and digitize the intermediate frequency signal. The sensor probe includes a microwave emitting probe configured to emit a microwave signal in a near field of a target region of an object to be measured and a microwave detecting probe configured to receive the near field microwave signal. And the sensor circuit is configured to process the microwave signal output by the radar chipset, input the microwave signal into the sensor probe and input the near-field microwave signal received by the sensor probe into the radar chipset.
Further, the radar chipset is mounted on a single printed circuit board that provides an integrated power module and system peripheral interfaces. The integrated power supply module comprises a low-dropout linear voltage regulator or an external power supply voltage interface.
Further, the radar chip set is packaged in C semiconductor chips, where C is an integer greater than or equal to 1, including: the radar waveform generator, the radar transmitter, the radar receiver, the analog-to-digital conversion passageway. A radar waveform generator configured to be externally connected to a reference frequency source and to generate a desired waveform and a local oscillator by frequency synthesis. A radar transmitter configured to power control or phase control N transmitted microwave signals, where N is an integer greater than or equal to 1. A radar receiver configured to receive M received microwave signals, where M is an integer greater than or equal to 1, and mix the received microwave signals and a reference microwave signal with a quadrature multiplier to obtain an intermediate frequency signal. An analog-to-digital conversion channel configured to filter, amplify, and digitize the intermediate frequency signal.
Further, the filtering is low-pass filtering or band-pass filtering.
A near-field microwave sensing detection method, the method comprising: mounting a radar chipset on a single printed circuit board implements a near field radar configured to generate a desired waveform, providing a plurality of microwave output channels and microwave input channels. The method comprises the steps of moving a microwave transmitting probe to a near field of a target area of a measured object, applying microwave signals generated by a near field radar to the target area of the measured object after the microwave signals are processed by a sensor circuit, receiving the near field microwave signals by the near field radar, inputting the near field microwave signals and reference microwave signals into an orthogonal multiplier in the near field radar for frequency mixing to obtain intermediate frequency signals, filtering, amplifying and digitizing the intermediate frequency signals. And a processor system manages the near-field radar, and calculates the absolute position or dielectric property of the target area of the measured object from the intermediate-frequency signal and the position of the sensor probe.
Further, in the near field microwave sensing signal processing apparatus or the detection method, the processor system includes a processor core, supports a cache and an external memory interface, and provides a system peripheral interface.
Further, in the near-field microwave sensing signal processing apparatus or the detection method, the waveform includes: continuous wave or frequency modulated continuous wave. The reference microwave signal is derived from the radar chipset frequency synthesis.
Further, in the near-field microwave sensing signal processing device or the detecting method, the sensor probe or the object to be detected is mounted on a position adjusting device, and the position adjusting device adjusts and controls a relative position of the sensor probe and a target region of the object to be detected. During measurement, the distance between the microwave transmitting probe and the target area of the measured object is smaller than the wavelength of the near-field microwave signal.
Further, in the near-field microwave sensing signal processing apparatus or the detection method, the sensor circuit includes a microwave resonator or a microwave transmission line.
Further, in the near-field microwave sensing signal processing apparatus or the detection method, the near-field microwave signal includes a reflected near-field microwave signal or a transmitted near-field microwave signal.
Compared with the prior art, the invention has the following beneficial effects.
1. All radar system modules of radar transmission, reception, frequency mixing, digitization, sensor signal processing and the like are realized by a microwave radar chipset integrated by a high signal chain. Based on the semiconductor technology capable of realizing large-scale production, the near-field microwave sensing signal processing device is higher in integration level, lower in power consumption, lighter in weight and higher in cost performance. It is easier to obtain, assemble and upgrade high quality solid state devices.
2. The spectrum range of the near-field microwave sensing system is easily expanded to millimeter waves. The sizes of the near-field microwave sensor and the circuit are reduced to millimeter level, the near-field microwave sensing signal processing device is more compact, and embedded application or handheld application can be realized.
3. The near-field microwave sensing signal processing device based on the vehicle-scale radar chipset has higher safety and reliability.
4. Chip and application manufacturers provide powerful radar chip set technology to develop software, hardware environment and ecosystem. The development speed of the near-field microwave sensing signal processing device is increased, and the development quality of the near-field microwave sensing signal processing device is improved.
5. The radar chip set can provide rich peripheral interaction interfaces or control bus interfaces for the near-field microwave sensing signal processing device. The near-field microwave sensing signal processing device and the position adjusting device are convenient to jointly debug and integrate. The application field of the near-field microwave sensing device is expanded.
6. And the near-field microwave sensing application of the microwave radar chip set is realized. The absolute position with high-speed measurement precision smaller than micrometer and the dielectric property of the target area of the measured object are quantitatively measured. The detectable frequency bandwidth of the vibration of the target area of the object to be measured can reach 5 MHz.
Drawings
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
fig. 1 shows a near field microwave sensing device based on a 24GHz radar chipset according to embodiment 1 of the present invention;
fig. 2 shows a near-field microwave sensing device based on a 77GHz radar chip according to embodiment 2 of the invention.
Corresponding numerals and symbols in the various drawings generally refer to corresponding parts unless otherwise indicated. The drawings are drawn to clearly illustrate relevant aspects of the preferred embodiments and are not necessarily to scale, the drawings being drawn to scale. To more clearly illustrate certain embodiments, words indicating variations in the same structure, material, or process step may follow the figure number.
Detailed Description
The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.
The following description shows various specific details to provide a thorough understanding of several example embodiments according to the present description.
Example 1:
in exemplary embodiment 1 of the present invention, a near field microwave sensing apparatus and a detection method based on a 24GHz radar chipset are provided to describe the present invention. The embodiment precisely determines the information such as the thickness or the complex dielectric constant of the target area of the object to be measured by emitting microwaves at one side of the object to be measured and detecting near-field microwaves at two sides of the object to be measured. The object to be tested can be a laminated substance such as a semiconductor wafer, glass, a substrate of a printed circuit board and the like.
The following describes each component of the near-field microwave sensing device of example 1 in detail.
Fig. 1 shows a near-field microwave sensing device of embodiment 1 of the present invention. In embodiment 1 of the present invention, the near field microwave sensing device includes a signal processing device and a motion platform 12. The signal processing device comprises a near-field radar, a near-field microwave sensor circuit and a sensor probe. The near-field radar comprises a radar waveform generator 1, a radar transmitter 2, a radar receiver 3, an analog-to-digital conversion channel 4 and a processor system 5, and is realized by a radar printed circuit board. The near field radar is installed on one side of the radar printed circuit board, the near field microwave sensor circuit is installed on the other side of the radar printed circuit board, and the sensor probe 10 is connected to the sensor circuit and installed on the side of the radar printed circuit board. The radar printed circuit board provides an integrated power module and a system peripheral interface. In embodiment 1 of the present invention, the integrated power supply module includes a low dropout regulator (LDO) to provide a low noise power supply for the near field radar. In some embodiments, the radar printed circuit board provides an external power supply voltage interface.
In some embodiments, the radar waveform generator, the radar transmitter, the radar receiver, and the analog-to-digital conversion channel are integrated in the same semiconductor chip. In other embodiments, the radar waveform generator, radar transmitter, radar receiver, and analog-to-digital conversion channel are integrated in C semiconductor chips, where C is an integer greater than 1. In some embodiments, the processor subsystem is further integrated into a chip of the radar chipset. In embodiment 1 of the present invention, the radar waveform generator 1 and the radar transmitter 2 are integrated in a radar transmitter chip, the radar receiver 3 is integrated in a radar analog front end chip, and the analog-to-digital conversion channel 4 is integrated in a multi-channel analog-to-digital conversion chip.
The spectrum of far-field microwave radar must meet the spectral regulations and standards set by the national telecommunication standardization institute. In a near field microwave sensing system, a sensor probe is within the near field range of a target area of an object to be measured. Lower microwave transmit power than far field applications can be used, and the operating spectrum range is more flexible than far field microwave radars.
In embodiment 1 of the present invention, a radar waveform generator 1 is externally connected to a 40MHz crystal oscillator 6, a 24GHz Voltage Controlled Oscillator (VCO) is integrated on a chip, covers an ISM frequency band (24 GHz to 24.25 GHz) of 250 MHz through frequency and power calibration, performs closed-loop control through a fractional-N phase-locked loop (PLL), provides a local oscillator, and generates a Continuous Wave (CW) or a highly linear Frequency Modulated Continuous Wave (FMCW). The frequency modulated continuous wave can be used to perform dielectric spectrum measurements of a target area of an object to be measured. The fractional-N pll achieves sub-hertz frequency resolution. Wherein, the working frequency of a Phase Frequency Detector (PFD) of the fractional-N frequency division phase-locked loop exceeds 100 MHz. At 1 MHz detuning, the phase noise of the radar waveform generator 1 is less than-100 dBc/Hz. The on-chip registers of the radar waveform generator 1 are all controlled by a simple four-wire serial peripheral interface (QSPI). It will be appreciated that the radar waveform generator may use different frequency synthesis techniques and may synthesize different spectral ranges. In some embodiments, the frequency synthesis employs direct digital frequency synthesis (DDS). In some embodiments, the frequency synthesis employs a direct analog synthesis technique.
In embodiment 1 of the present invention, radar transmitter 2 provides two transmitter channels, each of which contains a power control circuit. In some embodiments, the transmitter channel contains phase control circuitry.
In embodiment 1 of the present invention, the radar receiver 3 provides three receiver channels. Each receiver channel comprises a Low Noise Amplifier (LNA), a quadrature multiplier and the like, mixes the received microwave signal and the reference microwave signal and outputs two paths of intermediate frequency signals. In embodiment 1 of the present invention, the channel gain of the receiver channel is 22 dB. Vibration of the target area of the object to be measured or vibration of the sensor probe changes the frequency of the intermediate frequency signal. In embodiment 1 of the present invention, the frequency bandwidth of the vibration detectable frequency of the target region of the object to be measured 13 is 5 MHz.
In embodiment 1 of the present invention, the analog-to-digital conversion channel 4 provides six conversion channels, each having a gain range of 45 dB. Each conversion channel for optimizing dynamic range comprises: low Noise Amplifier (LNA), Programmable Gain Amplifier (PGA), and filters, all channels integrated with a 16-bit analog-to-digital converter (ADC). In embodiment 1 of the present invention, the signal bandwidth of the analog-to-digital converter is 5 MHz. At maximum gain, all channels are scaled to an input noise voltage of 3.5 nV/Hz. In embodiment 1 of the present invention, the filter is a low-pass anti-aliasing filter. In some embodiments, the analog-to-digital conversion result is filtered and serialized, and then the original analog-to-digital conversion data is provided to the outside through a serial data interface. Common serial data interfaces include: serial low voltage differential signaling interface (LVDS) or Camera Serial Interface (CSI).
In embodiment 1 of the present invention, the radar waveform generator 1 supplies a timing control signal to the analog-to-digital conversion channel 4.
In embodiment 1 of the present invention, a near-field microwave sensing detection method based on a 24GHz radar chipset includes: with radar transmitter chip, radar analog front end chip, multichannel analog-to-digital conversion chip install and realize the near field radar on radar printed circuit board, the near field radar is configured to the wave form and the local oscillator that produce the demand, provides 2 microwave output channels and 3 microwave input channels. The motion platform 12 moves the sensor probe 10 to the near field of the target area of the measured object 13, the microwave signal generated by the near field radar is processed by the sensor circuit and then applied to the target area of the measured object 13, the near field radar receives the near field microwave signal, the near field microwave signal and the reference microwave signal are input to an orthogonal multiplier in the near field radar to be mixed to obtain an intermediate frequency signal, and the intermediate frequency signal is filtered, amplified and digitized.
In embodiment 1 of the present invention, the processor system 5 manages near-field radar, and synchronously samples and calculates the detected near-field microwave amplitudes and phases of the sensor probe 10 and the probe 11 for the intermediate frequency signal obtained by the orthogonal frequency mixing. The position of the sensor probe provided in conjunction with the motion stage 12 can further calculate information such as absolute position, thickness, vibration or dielectric constant of the target area of the object 13 to be measured.
In some embodiments, a processor system includes a plurality of processors, each having one or more processor cores. In some embodiments, a processor system includes a single processor having one or more processor cores. Wherein the processor core comprises a general purpose processor core or a micro control processor core or a Digital Signal Processor (DSP) core. In embodiment 1 of the present invention, the processor system 5 employs a low power consumption Blackfin + embedded digital processor, and employs a RISC architecture Blackfin + digital processor core, with an operating frequency of 400 MHz. On-chip level one and level two caches are supported, including random access memory (SRAM) and Read Only Memory (ROM). A DDR2 memory interface is provided. The system comprises an inter-integrated circuit interface (I2C), a Serial Peripheral Interface (SPI), a universal serial data bus interface (UART), a general input/output port (GPIO), a four-wire serial peripheral interface (QSPI), a CAN bus interface, an 8-bit SD/SDIO/MMC flash memory interface and other system peripheral interfaces. The processor system 5 manages the radar waveform generator 1, the radar transmitter 2, the radar receiver 3 and the analog-to-digital conversion channel 4 through system peripheral interfaces such as a serial peripheral interface, a universal input/output port and the like. In embodiment 1 of the present invention, the processor system 5 implements a sensor algorithm and a human-computer interaction interface. The sensor algorithm includes calculating information such as absolute position, thickness, vibration or dielectric constant of the target area of the object to be measured 13 from the intermediate frequency signals, the position of the sensor probe 10 and the position of the sensor probe 11.
In embodiment 1 of the present invention, the position adjusting means is implemented by the moving platform 12, and communicates position measurement and control information with the signal processing apparatus through a system peripheral interface. The motion platform 12 moves the radar printed circuit board, fixing the sensor probe 11. In some embodiments, the position adjustment device moves the object under test. In some embodiments, the position adjustment device moves the sensor probe and the object to be measured simultaneously.
In embodiment 1 of the present invention, the near-field microwave sensor circuit includes a microwave circulator 8 and a half-wavelength microstrip line microwave resonator 9 having a center frequency of 24.125 GHz. The microwave circulator 8 functions to separate the incident microwave signal from the reflected microwave signal. The microwave circulator 8 may be replaced by a microwave directional coupler. The half wavelength of the center frequency of the half wavelength microstrip line microwave resonator 9 is about 6.22 mm, which is suitable for embedded or palm applications. In some embodiments, the near field microwave sensor circuit includes a frequency shifting device that shifts the frequency of the radar chipset frequency synthesized signal or the near field microwave signal or the intermediate frequency signal.
In embodiment 1 of the present invention, the distance from the sensor probe to the target region of the measured object 13 during measurement can be less than 10 microns, which is much less than the wavelength of the near-field microwave signal.
In some embodiments, the reference microwave signal is a local oscillator. In some embodiments, the reference microwave signal is derived by frequency shifting a signal frequency synthesized by the radar chipset. In embodiment 1 of the present invention, the reference microwave signal is a local oscillator.
In embodiment 1 of the present invention, the sensor probe includes a sensor probe 10 and a sensor probe 11, and is located on both sides of a measured object 13. The sensor probe 10 is a metal ball with a diameter of less than 100 microns and is used for both microwave transmission and reception of reflected near field microwave signals. The sensor probe 11 is a metal ball with a diameter less than 100 microns for receiving the transmitted near field microwave signal. By using the spherical symmetrical sensor probe, a sensor signal processing model can be greatly simplified, and the geometric structure information and the dielectric property information of the target area of the measured object 13 are accurately decoupled. It should be understood that the sensor probe may have different sizes and may also have different shapes.
Example 2:
the far-field 77GHz radar chip provides a wide scanning bandwidth of up to 4GHz, can utilize a wider bandwidth and a higher radio frequency to improve the accuracy of measuring distance and speed, obviously reduces the size of a sensor, and gradually becomes the mainstream of the far-field radar chip. In exemplary embodiment 2 of the present invention, a near field microwave sensing apparatus and a detection method based on a 77GHz radar chip are provided to describe the present invention. The embodiment can be used for nondestructively, contactlessly and rapidly measuring the absolute position change of the target area of the measured surface, which is less than microns, and accurately detecting the high-speed motion and vibration of the target area of the measured surface. The analog-digital sampling speed of the microwave radar chip can exceed 10MHz, and the detectable frequency bandwidth of the vibration of the target area of the object to be detected can reach 5 MHz. Further, this embodiment can also be used to quantitatively measure the dielectric properties of a target area of an object without contacting the object.
The respective constituent parts of the near-field microwave sensing device of example 2 are explained in detail below.
Fig. 2 shows a near-field microwave sensing device based on a 77GHz radar chip according to embodiment 2 of the present invention. In embodiment 2 of the present invention, the near field microwave sensing device includes a signal processing device and a moving platform 21. The signal processing means comprises a microwave radar 14, a near-field microwave sensor circuit and a sensor probe 19, implemented by a radar printed circuit board. The microwave radar 14 is mounted on one surface of the radar printed circuit board, the near field microwave sensor circuit is mounted on the other surface of the radar printed circuit board, and the sensor probe 19 is connected to the near field microwave sensor circuit and mounted on the side surface of the radar printed circuit board. The printed circuit board provides an integrated power module and a system peripheral interface. The integrated power supply module comprises a low dropout linear regulator which provides fixed output voltages of 1.2V, 1.3V, 1.8V and 3.3V with low output noise.
In embodiment 2 of the present invention, the microwave radar 14 is manufactured by 45 nm low power consumption RFCMOS process, and the radar waveform generator, the radar transmitter, the radar receiver, the analog-to-digital conversion channel, and the radar processor system are integrated in the chip. The external 40MHz crystal oscillator 22, the on-chip radar waveform generator has integrated microwave synthesizer and timing engine based on fractional N frequency division phase-locked loop, and generates microwave continuous wave or frequency modulation continuous wave with local oscillator and working frequency of 76GHz to 81 GHz. The 1 MHz offset phase noise is lower than-90 dBc/Hz. The on-chip radar transmitter provides 2 parallel transmitting channels, and power control or phase control is respectively carried out on each transmitting microwave signal. The on-chip radar receiver provides 4 parallel receive channels, each microwave receive channel including a Low Noise Amplifier (LNA) and a quadrature multiplier. The on-chip radar receiver receives the microwave signal, amplifies the microwave signal with low noise, and mixes the microwave signal with a reference microwave signal by using an orthogonal multiplier to obtain an intermediate frequency signal. And filtering, amplifying and digitizing the intermediate frequency signal by an on-chip analog-to-digital conversion channel. The switched channel has a gain range of 24 dB to 48 dB. The maximum number of samples per second of analog-to-digital conversion is 12.5M. In embodiment 2 of the present invention, raw analog-to-digital conversion data is externally supplied through a serial low voltage differential signaling interface (LVDS). In embodiment 2 of the present invention, the filter is a band pass filter, the low frequency cutoff frequency is 150KHz, and the bandwidth is 5 MHz.
In embodiment 2 of the present invention, the timing engine provides timing control signals to the on-chip analog-to-digital conversion channels.
In embodiment 2 of the present invention, a near-field microwave sensing detection method based on a 77GHz radar chip includes: the 77GHz radar chip is installed on a radar printed circuit board to realize a near field radar, and the near field radar is configured to generate required waveforms and local oscillators and provide 2 microwave output channels and 4 microwave input channels. The motion platform 21 moves the sensor probe 19 to the near field of the target area of the measured object 20, the microwave signal generated by the near field radar is processed by the sensor circuit and then applied to the target area of the measured object 20, the near field radar receives the near field microwave signal, the near field microwave signal and the reference microwave signal are input to an orthogonal multiplier in the near field radar to be mixed to obtain an intermediate frequency signal, and the intermediate frequency signal is filtered, amplified and digitized.
In embodiment 2 of the present invention, the on-chip radar processor system manages the near-field radar, synchronously samples and calculates the impedance of the sensor probe 19 for two intermediate frequency signals obtained by the orthogonal frequency mixing, and further calculates the absolute position or dielectric characteristic of the target region of the object 20 to be measured from the impedance of the sensor probe 19 and the position of the sensor probe 19 provided by the motion platform 21.
In embodiment 2 of the present invention, the radar processor system includes a microcontroller system and a digital signal processor system on a chip. The microcontroller system includes a Cortex-R4F processor core, a bus, a direct memory access controller, and a Cyclic Redundancy Check (CRC) engine module; an inter-integrated circuit interface (I2C), a Serial Peripheral Interface (SPI), a universal serial bus interface (UART), a general input/output port (GPIO), a four-wire serial peripheral interface (QSPI), a CAN bus interface or a CAN-FD bus interface or a pulse width modulation interface (PWM) and other system peripheral interfaces are provided. In embodiment 2 of the present invention, an on-chip integrated digital signal processor system comprises a digital signal processing core, a 128-bit 200MHz high performance system bus, 4 direct memory access controllers, a Cyclic Redundancy Check (CRC) engine module, an on-chip cache, and a memory interface. In embodiment 2 of the present invention, the digital signal processor system provides a serial low voltage differential signal interface for measurement data. In embodiment 2 of the present invention, a processor system provides two startup modes, including: starting the external device through the serial peripheral interface; the serial flash memory 15 is started, and the flash memory 15 is connected with the microwave radar 14 through a serial peripheral interface. In some embodiments, the complex near-field sensing application or program may have more memory and a more powerful processor system external to the complex near-field sensing application or program through a high-speed data interface or a system peripheral interface. In embodiment 2 of the present invention, the processor system implements a sensor algorithm and a human-computer interaction interface. The sensor algorithm includes calculating the absolute position or dielectric properties of the target area of the object 20 from the intermediate frequency signals and the position of the sensor probe 19.
In embodiment 2 of the present invention, the near-field microwave sensor circuit further includes a microwave directional coupler 17 and a half-wavelength microstrip line microwave resonator 18 having a center frequency of 78 GHz. The half wavelength of the center frequency of the half wavelength microstrip line microwave resonator 18 is about 1.92 mm, which is suitable for embedded or palm applications. In embodiment 2 of the present invention, the near field microwave sensor circuit further includes a frequency shift device 16, and the frequency shift bandwidth is 5 MHz.
During measurement, the distance between the sensor probe 19 and the target area of the measured object 20 is less than the wavelength of the near-field microwave signal.
In embodiment 2 of the invention, the reference microwave signal is derived from an on-chip radar waveform generator frequency synthesis.
In embodiment 2 of the present invention, the sensor probe 19 is a metal ball having a diameter of less than 100 μm, and is used for both microwave transmission and reception of reflected near-field microwave signals.
While the invention has been described with reference to a preferred embodiment, this description is not intended to be construed in a limiting sense. It would be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A near-field microwave sensing signal processing apparatus, comprising: the radar chip set, the sensor probe and the sensor circuit;
a radar chipset configured to generate a desired waveform, transmit and receive microwave signals, mix to obtain an intermediate frequency signal, filter, amplify, digitize the intermediate frequency signal;
the sensor probe comprises a microwave transmitting probe and a microwave detecting probe, wherein the microwave transmitting probe is configured to transmit a microwave signal in a near field of a target area of a measured object, and the microwave detecting probe is configured to receive the near field microwave signal;
and the sensor circuit is configured to process the microwave signal output by the radar chipset, input the microwave signal into the sensor probe and input the near-field microwave signal received by the sensor probe into the radar chipset.
2. A near field microwave sensing signal processing apparatus according to claim 1, wherein the radar chipset is mounted on a single printed circuit board, the printed circuit board provides an integrated power module and a system peripheral interface, and the integrated power module includes a low dropout linear regulator or an external power voltage interface.
3. A near-field microwave sensing signal processing device according to claim 1, wherein the radar chip group is packaged in C semiconductor chips, where C is an integer of 1 or more, and includes: the system comprises a radar waveform generator, a radar transmitter, a radar receiver and an analog-digital conversion channel;
a radar waveform generator configured to be externally connected to a reference frequency source, and to generate a desired waveform and a local oscillator by frequency synthesis;
a radar transmitter configured to power control or phase control N transmitted microwave signals, where N is an integer greater than or equal to 1;
a radar receiver configured to receive M received microwave signals, where M is an integer greater than or equal to 1, and mix the received microwave signals and a reference microwave signal with a quadrature multiplier to obtain an intermediate frequency signal;
an analog-to-digital conversion channel configured to filter, amplify, and digitize the intermediate frequency signal.
4. A near-field microwave sensing signal processing device according to claim 3, characterized in that the filtering is low-pass filtering or band-pass filtering.
5. A near-field microwave sensing detection method, the method comprising:
mounting a radar chipset on a single printed circuit board to implement a near field radar configured to generate a desired waveform, providing a plurality of microwave output channels and microwave input channels;
moving a microwave transmitting probe to a near field of a target area of a measured object, processing a microwave signal generated by a near field radar through a sensor circuit, applying the processed microwave signal to the target area of the measured object, receiving the near field microwave signal by the near field radar, inputting the near field microwave signal and a reference microwave signal into an orthogonal multiplier in the near field radar for frequency mixing to obtain an intermediate frequency signal, filtering, amplifying and digitizing the intermediate frequency signal;
and a processor system manages the near-field radar, and calculates the absolute position or dielectric property of the target area of the measured object from the intermediate-frequency signal and the position of the sensor probe.
6. A near field microwave sensing signal processing apparatus or detection method according to claims 1 to 5, wherein the processor system includes a processor core supporting a cache and an external memory interface, providing a system peripheral interface.
7. A near-field microwave sensing signal processing apparatus or detection method according to claims 1 to 5, characterized in that the waveform comprises: continuous wave or frequency modulated continuous wave, the reference microwave signal is derived from the radar chip set frequency synthesis.
8. The near-field microwave sensing signal processing device or the detecting method according to claims 1 to 5, wherein the sensor probe or the object to be detected is mounted on a position adjusting device, and the position adjusting device adjusts and controls a relative position of the sensor probe and a target region of the object to be detected; during measurement, the distance between the microwave transmitting probe and the target area of the measured object is smaller than the wavelength of the near-field microwave signal.
9. A near field microwave sensing signal processing apparatus or detection method according to claims 1 to 5, characterized in that the sensor circuit comprises a microwave resonator or a microwave transmission line.
10. A near-field microwave sensing signal processing apparatus or a near-field microwave sensing signal detection method according to claims 1 to 5, wherein the near-field microwave signal comprises a reflected near-field microwave signal or a transmitted near-field microwave signal.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116643280A (en) * | 2023-07-27 | 2023-08-25 | 禾昆科技(北京)有限公司 | Radar control device and radar control method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116643280A (en) * | 2023-07-27 | 2023-08-25 | 禾昆科技(北京)有限公司 | Radar control device and radar control method |
| CN116643280B (en) * | 2023-07-27 | 2023-10-13 | 禾昆科技(北京)有限公司 | Radar control device and radar control method |
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