A miniaturized electromagnetic sensor

Abstract

The present invention relates to a miniaturized electromagnetic sensor, comprising: a frequency synthesizer and a broadband antenna, a radio frequency front-end module, an intermediate frequency processing module and an output interface connected in sequence, wherein the broadband antenna is used to sense space electromagnetic signals; the radio frequency front-end module comprises a radio frequency switch array and a plurality of radio frequency channels integrated on the same chip using bonding technology, the radio frequency switch array connects space electromagnetic signals of different frequencies to different radio frequency channels respectively, and a mixer is provided in any radio frequency channel, the mixer down-converts the space electromagnetic signal in the radio frequency channel into an intermediate frequency signal of a specific frequency; the intermediate frequency processing module down-converts the intermediate frequency signal of the specific frequency into a baseband digital signal to output the characteristic information of the space electromagnetic signal. The technical solution of the present invention can solve the problem that the traditional electromagnetic signal measuring equipment is large in size and inconvenient to move, and cannot realize on-site electromagnetic compatibility measurement and evaluation of working equipment, especially aircraft equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic sensors, and in particular to a miniaturized electromagnetic sensor. Background Art

[0002] Electromagnetic interference refers to the interference of strong electrical or external electromagnetic signals on electronic equipment and systems, which causes the equipment to have reduced performance or malfunction. When the equipment is working, due to different environments, it may be affected by the surrounding interference sources, causing abnormal operation of the equipment, which has caused great harm in the military and civilian fields.

[0003] Although our country or other countries have formulated strict inspection specifications and standards for each electronic device before it leaves the factory, such as establishing many electromagnetic compatibility microwave darkrooms to test the reliability of electronic equipment through various tests. However, the tests are often carried out in a static environment (or the electronic equipment is not fully in working condition), or only the electronic equipment is tested separately. In fact, modern equipment or equipment has a large number of radio equipment or electronic equipment in a limited working environment at the same time, and the working signal is easily interfered, making the work of troubleshooting electromagnetic compatibility increasingly complicated. This urgently requires a sensor for on-site electromagnetic environment testing, which can measure and evaluate the on-site electromagnetic compatibility of working equipment, and has important guiding significance for product research and development and production.

[0004] Equipment for electromagnetic measurement is currently mainly concentrated in foreign manufacturers, such as the WR-G39DDCe product developed by WINRADIO in Australia, the SigMon system of SAT in the United States, and the E3238S / N6820E dedicated radio signal monitoring system (commonly known as Blackbird) of Agilent in the United States. Some domestic research institutes also have follow-up products, all of which have the following characteristics:

[0005] Expensive and high maintenance cost.

[0006] Large size: Mainly used in research rooms or laboratories, not easy to integrate with the system.

[0007] Standardized instruments: complex functions, requiring professional operation.

[0008] No antenna is provided and is not compatible with dedicated systems. Summary of the invention

[0009] In view of this, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a miniaturized electromagnetic sensor to solve the problem that traditional electromagnetic signal measuring equipment is large in size and inconvenient to move, making it impossible to perform on-site electromagnetic compatibility measurement and evaluation of working equipment, especially aircraft equipment.

[0010] To achieve the above objectives, the present invention adopts the following technical solutions:

[0011] A miniaturized electromagnetic sensor includes: a frequency synthesizer and a broadband antenna, a radio frequency front-end module, an intermediate frequency processing module and an output interface connected in sequence, wherein:

[0012] The broadband antenna is used to sense space electromagnetic signals; the RF front-end module includes a RF switch array and multiple RF channels integrated on the same chip using bonding technology, the RF switch array is used to connect space electromagnetic signals of different frequencies to different RF channels respectively, any of the RF channels is provided with a mixer, the mixer is used to down-convert the space electromagnetic signal in the RF channel into an intermediate frequency signal of a specific frequency; the frequency synthesizer is used to provide a down-converted local oscillation signal for each RF channel under the control of the intermediate frequency processing module;

[0013] The intermediate frequency processing module is used to down-convert the intermediate frequency signal of the specific frequency into a baseband digital signal, and process the baseband digital signal to output characteristic information of the spatial electromagnetic signal; wherein the characteristic information of the spatial electromagnetic signal includes: frequency, amplitude and phase.

[0014] Preferably, any of the radio frequency channels is also provided with a bandpass filter, a low noise amplifier, a variable gain amplifier and a low pass filter; the bandpass filter, the low noise amplifier, the mixer, the variable gain amplifier and the low pass filter are connected in sequence.

[0015] Preferably, the radio frequency switch array comprises a first radio frequency switch array and a second radio frequency switch array, wherein:

[0016] The input end of the first RF switch array is connected to the broadband antenna, and the output end is connected to the bandpass filter of each RF channel; the input end of the second RF switch array is connected to the low-pass filter of each RF channel, and the output end is connected to the intermediate frequency processing module;

[0017] The first RF switch array is used to connect spatial electromagnetic signals of different frequencies to different RF channels respectively; the second RF switch array is used to transmit the intermediate frequency signal of a specific frequency output by each RF channel to the intermediate frequency processing module according to a preset timing.

[0018] Preferably, the intermediate frequency processing module includes a radio frequency transceiver and a processor connected to the radio frequency transceiver, wherein:

[0019] The RF transceiver is used to receive the intermediate frequency signal of the specific frequency transmitted by each RF channel, and convert the intermediate frequency signal of the specific frequency into a baseband digital signal and output it to the processor; the processor is used to analyze and calculate the baseband digital signal and output the characteristic information of the spatial electromagnetic signal.

[0020] Preferably, the processor comprises:

[0021] A windowing module, used for performing a windowing operation on the baseband digital signal output by the radio frequency transceiver to obtain a baseband digital signal within a specific time domain range;

[0022] An FFT module is used to perform an FFT operation on the baseband digital signal within the specific time domain range to obtain a frequency domain response signal;

[0023] A modulo module, used for performing a modulo operation on the frequency domain response signal to obtain a spectrum amplitude value of the spatial electromagnetic signal;

[0024] The data preprocessing module is used to compress the frequency domain response signal and send it to an external device through the output interface.

[0025] Preferably, the radio frequency transceiver uses an AD9361 integrated transceiver chip, and the processor uses a ZYNQ7020 series AP-SOC chip.

[0026] Preferably, the SPI interface derived from the processor is connected to the SPI control interface of AD936 for configuring parameters of AD9361.

[0027] Preferably, the processor is externally connected to a 2000MB DDR chip and is also provided with an SD card interface;

[0028] The baseband data interface of AD9361 is connected to the PL end of the processor. The processor sends the received baseband digital signal to the DDR chip through the AXI bus connected to the internal AXI-DMA through timing matching and control.

[0029] Preferably, the broadband antenna comprises a loop antenna for sensing low-frequency space electromagnetic signals and a conical antenna for sensing high-frequency space electromagnetic signals.

[0030] Preferably, the miniaturized electromagnetic sensor further includes a shell, on which a plurality of antenna interfaces are provided, and the broadband antenna is pluggably arranged in the antenna interface; the RF front-end module and the intermediate frequency processing module are arranged in the shell, and the output interface is embedded in the shell.

[0031] The present invention adopts the above technical solution and has at least the following beneficial effects:

[0032] Due to its unique advantages in assembly efficiency, signal transmission speed, electrical performance, etc., multi-chip microwave (MCM) has entered the stage of full application. It has the remarkable characteristics of high wiring density, short interconnection lines, small size, light weight and excellent performance. The miniaturized electromagnetic sensor provided by the present invention, the RF front-end module includes an RF switch array and multiple RF channels integrated on the same chip using bonding technology, and the RF front-end module uses microwave bonding technology to miniaturize the whole machine (in specific practice, the miniaturized electromagnetic sensor provided by the present invention can be reduced to a volume of only 165mmx100mmx65mm, with a tolerance of ±0.1mm), and maximizes the performance of high-integration and high-speed semiconductor ICs, thereby reducing the volume of the electromagnetic sensor, so that it can be integrated inside the working equipment or installed around the working equipment, solving the problem that the traditional electromagnetic signal measurement equipment is large in size and inconvenient to move, and cannot realize on-site electromagnetic compatibility measurement and evaluation of working equipment, especially aircraft equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 An overall schematic block diagram of a miniaturized electromagnetic sensor provided by an embodiment of the present invention;

[0035] Figure 2 A schematic block diagram of a radio frequency front-end module provided in one embodiment of the present invention;

[0036] Figure 3 A schematic block diagram of an intermediate frequency processing module provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0038] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

[0039] See also Figure 1 and Figure 2An embodiment of the present invention provides a miniaturized electromagnetic sensor, comprising: a frequency synthesizer 1 and a broadband antenna 2, a radio frequency front-end module 3, an intermediate frequency processing module 4 and an output interface 5 connected in sequence.

[0040] The broadband antenna 2 is used to sense space electromagnetic signals; the RF front-end module 3 includes a RF switch array and multiple RF channels integrated on the same chip using bonding technology, the RF switch array is used to connect space electromagnetic signals of different frequencies to different RF channels respectively, and any of the RF channels is provided with a mixer 31, the mixer 31 is used to down-convert the space electromagnetic signal in the RF channel into an intermediate frequency signal of a specific frequency; the frequency synthesizer 1 is used to provide a down-converted local oscillation signal for each RF channel under the control of the intermediate frequency processing module 4;

[0041] The intermediate frequency processing module 4 is used to down-convert the intermediate frequency signal of the specific frequency into a baseband digital signal, and process the baseband digital signal to output characteristic information of the spatial electromagnetic signal; wherein the characteristic information of the spatial electromagnetic signal includes: frequency, amplitude and phase.

[0042] It is understandable that due to its unique advantages in assembly efficiency, signal transmission speed, electrical performance, etc., multi-chip microwave (MCM) has entered the stage of full application. It has the remarkable characteristics of high wiring density, short interconnection lines, small size, light weight and excellent performance. The miniaturized electromagnetic sensor provided by the present invention, the RF front-end module 3 includes an RF switch array and multiple RF channels integrated on the same chip using bonding technology. The RF front-end module 3 uses microwave bonding technology to miniaturize the whole machine and maximize the performance of high-integration and high-speed semiconductor ICs, thereby reducing the size of the electromagnetic sensor, so that it can be integrated inside the working equipment or installed around the working equipment, solving the problem that the traditional electromagnetic signal measurement equipment is large in size and inconvenient to move, and cannot realize on-site electromagnetic compatibility measurement and evaluation of working equipment, especially aircraft equipment.

[0043] See also Figure 2 Preferably, any of the RF channels is also provided with a bandpass filter, a low noise amplifier, a variable gain amplifier and a low pass filter; the bandpass filter 34, the low noise amplifier 35, the mixer 31, the variable gain amplifier 36 and the low pass filter 37 are connected in sequence.

[0044] Preferably, the RF switch array includes a first RF switch array 32 and a second RF switch array 33, wherein:

[0045] The input end of the first RF switch array 32 is connected to the broadband antenna 2, and the output end is connected to the bandpass filter 34 of each RF channel; the input end of the second RF switch array 33 is connected to the low-pass filter 37 of each RF channel, and the output end is connected to the intermediate frequency processing module 4;

[0046] The first RF switch array 32 is used to connect spatial electromagnetic signals of different frequencies to different RF channels respectively; the second RF switch array 33 is used to transmit the intermediate frequency signal of a specific frequency output by each RF channel to the intermediate frequency processing module 4 according to a preset timing.

[0047] It should be noted that the broadband antenna 2 of the miniaturized electromagnetic sensor provided by the present invention can sense the space electromagnetic signal of 9kHz to 41GHz, and the frequency of the space electromagnetic signal processed by each radio frequency channel is continuously adjustable and has equal bandwidth. For example, the first radio frequency channel processes the space electromagnetic signal of 9KHz to 2009KHz, the second radio frequency channel processes the space electromagnetic signal of 2010KHz to 4010KHz, the third radio frequency channel processes the space electromagnetic signal of 4011KHz to 6011KHz, and so on.

[0048] It is understandable that the frequency of the local oscillator signal used for down-conversion in each RF channel is also continuously adjustable, generated by the frequency synthesizer 1, and respectively transmitted to the mixer 31 in each RF channel for down-conversion of the spatial electromagnetic signal. The center frequency and the upper and lower cutoff frequencies of the bandpass filter 34 of each RF channel are also different.

[0049] It should be noted that the specific frequency is 325.5 MHz.

[0050] It can be understood that the miniaturized electromagnetic sensor provided by the present invention first divides the spatial electromagnetic signal sensed by the broadband antenna 2 into equal bandwidths and then performs frequency mixing. Before and after frequency mixing, windowing and noise filtering are performed by the bandpass filter 34 respectively. After frequency mixing, the output intermediate frequency signal of the specific frequency is filtered again by the low-pass filter 37, which effectively suppresses the interference of environmental noise and realizes low loss of radio frequency signal and good signal-to-noise ratio reception.

[0051] Preferably, the intermediate frequency processing module 4 includes a radio frequency transceiver and a processor connected to the radio frequency transceiver, wherein:

[0052] The RF transceiver is used to receive the intermediate frequency signal of the specific frequency transmitted by each RF channel, and convert the intermediate frequency signal of the specific frequency into a baseband digital signal and output it to the processor; the processor is used to analyze and calculate the baseband digital signal and output the characteristic information of the spatial electromagnetic signal.

[0053] Preferably, the processor comprises:

[0054] A windowing module, used for performing a windowing operation on the baseband digital signal output by the radio frequency transceiver to obtain a baseband digital signal within a specific time domain range;

[0055] An FFT module is used to perform an FFT operation on the baseband digital signal within the specific time domain range to obtain a frequency domain response signal;

[0056] A modulo module, used for performing a modulo operation on the frequency domain response signal to obtain a spectrum amplitude value of the spatial electromagnetic signal;

[0057] The data preprocessing module is used to compress the frequency domain response signal and send it to an external device through the output interface 5.

[0058] See also Figure 3 Preferably, the RF transceiver uses the AD9361 integrated transceiver chip, and the processor uses the ZYNQ7020 series AP-SOC chip.

[0059] It should be noted that the decomposition of electromagnetic sensor computing tasks should not be too coarse or too fine. Too coarse will increase the complexity of logic design, while too fine will increase the complexity of underlying software design due to too many logic IP cores. Therefore, the decomposition method should try to reduce the combined complexity of logic and software.

[0060] In the design of electromagnetic sensors, the analysis and calculation tasks of electromagnetic signals are coarsely decomposed into four tasks: windowing, FFT, modulo, and data preprocessing. When the user layer analyzes the electromagnetic signal data, it will select the window function type, determine the number of FFT operation points, and determine whether the displayed result is amplitude or phase according to the requirements. At the same time, the three operation processes of windowing, FFT, and modulo are carried out in sequence without interference. The IP core is encapsulated according to the above standards, and the data is processed in three stages of pipelines between each hardware IP core.

[0061] The specific instructions are as follows:

[0062] 1. Windowing: When performing frequency domain analysis on baseband digital signals, windowing is a common processing method to prevent spectrum leakage caused by signal truncation. Data windowing requires multiplication operations, which consumes a lot of time for processors without hardware multipliers. Using the programmable logic resources inside the processor PL for parallel processing will greatly save time.

[0063] 2. FFT operation: The most important part of spectrum analysis is to transform the signal from time domain to frequency domain. FFT is used to transform the time domain signal to frequency domain for analysis. FFT operation requires a large number of multiplication and accumulation operations, which is very time-consuming. The amount of operation will increase exponentially with the increase of operation points. Therefore, in order to speed up the operation, hardware is generally used for parallel operation.

[0064] The present invention implements radix-4 FFT transformation by calling the IP core provided by the processor, which can multiplex the input memory and the output memory, thereby effectively reducing the resource consumption of the on-chip FPGA. By increasing the working clock of the system, the FFT operation can reach a very high speed.

[0065] 3. Modulus: After FFT operation, the result appears in the form of complex number, and when performing spectrum analysis, it is generally necessary to know the spectrum amplitude of the signal, that is, the value after complex modulus. The present invention uses IPCore provided by XILINX to perform modulus square root and optimizes the process.

[0066] 4. Data preprocessing: Due to the large amount of data storage, in order to perform real-time analysis, a complex compression algorithm is used internally when the data is sent out, compressing the original data rate from 5MB / s to about 1MB / s.

[0067] Preferably, the SPI interface derived from the processor is connected to the SPI control interface of AD936 for configuring parameters of AD9361.

[0068] Preferably, the processor is externally connected to a 2000MB DDR chip and is also provided with an SD card interface;

[0069] The baseband data interface of AD9361 is connected to the PL end of the processor. The processor sends the received baseband digital signal to the DDR chip through the AXI bus connected to the internal AXI-DMA through timing matching and control.

[0070] It is understandable that when performing real-time spectrum analysis on the electromagnetic signal of the device under test, the time for one frame of FFT transformation is required to be less than the time for one frame of data acquisition, so as to ensure that the trigger is real-time. At present, most baseband digital signal processing uses special signal processing devices such as DSP for processing. Its advantage is that all processing can be implemented by software, and the design is very flexible and controllable. However, since DSP is a serial processing device, its processing speed is not enough to meet the processing speed requirements of real-time spectrum analysis, and it is generally used in non-real-time spectrum analysis or real-time analysis and processing of low-frequency bands.

[0071] In order to achieve the requirements of high-speed real-time processing, hardware must be used for parallel processing. As a programmable logic device, FPGA's parallel processing characteristics can make the data processing speed meet the requirements of real-time signal processing and analysis. Although FPGA has good performance in parallel processing, it is far less flexible than processing devices such as DSP, and is relatively complex in the implementation of complex data flow conversion control, application decision-making, etc. The small electromagnetic sensor provided by the present invention uses the zynq-7000 series AP-SOC launched by Xilinx, which integrates a high-performance dual-core cotex-A9 processor core and FPGA inside the chip. The internal PS (processor system) and PL (processing logic) flexible interaction mechanism developed and defined by Xilinx, all time-consuming signal processing work can be handed over to the internal hardware logic PL, while complex data control and decision processing are handed over to the on-chip PS to complete. In this way, it can meet the requirements for high-speed processing of baseband digital signals and have the flexibility of complex logic control.

[0072] Preferably, the broadband antenna 2 includes a loop antenna for sensing low-frequency space electromagnetic signals and a conical antenna for sensing high-frequency space electromagnetic signals.

[0073] It is understandable that the spatially mixed electromagnetic waves contained in the test environment will also be monitored as the electromagnetic field radiated by the target. In near-field measurement, the target to be measured can be quickly scanned with a probe with known electrical characteristics within a range of 3 to 10 wavelengths from the target to be measured, and the electrical signal can be converted into a transform domain signal (FFT) for analysis. In far-field measurement, a dedicated antenna is used for measurement.

[0074] Therefore, the broadband antenna 2 is divided into two types: a loop antenna for sensing low-frequency space electromagnetic signals and a conical antenna for sensing high-frequency space electromagnetic signals.

[0075] Preferably, the miniaturized electromagnetic sensor also includes a shell, on which a plurality of antenna interfaces are provided, and the broadband antenna 2 is pluggably arranged in the antenna interface; the RF front-end module 3 and the intermediate frequency processing module 4 are arranged in the shell, and the output interface 5 is embedded in the shell.

[0076] It should be noted that the miniaturized electromagnetic sensor provided by the present invention has reserved a variety of interfaces, such as RS422 interface, Ethernet interface, etc., to facilitate integration with external systems.

[0077] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The term "plurality" refers to two or more, unless otherwise clearly defined.

Claims

1. A miniaturized electromagnetic sensor, characterized in that: include: The frequency synthesizer and the broadband antenna, RF front-end module, intermediate frequency processing module and output interface connected in sequence, wherein: The broadband antenna is used to sense space electromagnetic signals; the RF front-end module includes a RF switch array and multiple RF channels integrated on the same chip using bonding technology, the RF switch array is used to connect space electromagnetic signals of different frequencies to different RF channels respectively, any of the RF channels is provided with a mixer, the mixer is used to down-convert the space electromagnetic signal in the RF channel into an intermediate frequency signal of a specific frequency; the frequency synthesizer is used to provide a down-converted local oscillation signal for each RF channel under the control of the intermediate frequency processing module; wherein the bonding technology is microwave bonding technology; The intermediate frequency processing module is used to down-convert the intermediate frequency signal of the specific frequency into a baseband digital signal, and process the baseband digital signal to output characteristic information of the space electromagnetic signal; wherein the characteristic information of the space electromagnetic signal includes: frequency, amplitude and phase; Wherein, any of the radio frequency channels is also provided with a bandpass filter, a low noise amplifier, a variable gain amplifier and a low pass filter; the bandpass filter, the low noise amplifier, the mixer, the variable gain amplifier and the low pass filter are connected in sequence; The radio frequency switch array includes a first radio frequency switch array and a second radio frequency switch array, wherein: The input end of the first RF switch array is connected to the broadband antenna, and the output end is connected to the bandpass filter of each RF channel; the input end of the second RF switch array is connected to the low-pass filter of each RF channel, and the output end is connected to the intermediate frequency processing module; The first RF switch array is used to connect spatial electromagnetic signals of different frequencies to different RF channels respectively; the second RF switch array is used to transmit the intermediate frequency signals of specific frequencies output by each RF channel to the intermediate frequency processing module according to a preset timing; The intermediate frequency processing module includes a radio frequency transceiver and a processor connected to the radio frequency transceiver, wherein the radio frequency transceiver is used to receive the intermediate frequency signal of the specific frequency transmitted by each radio frequency channel, and convert the intermediate frequency signal of the specific frequency into a baseband digital signal and output it to the processor; the processor is used to analyze and calculate the baseband digital signal, and output the characteristic information of the space electromagnetic signal; The processor includes: a windowing module, which is used to perform a windowing operation on the baseband digital signal output by the radio frequency transceiver to obtain a baseband digital signal within a specific time domain range; an FFT module, which is used to perform an FFT operation on the baseband digital signal within the specific time domain range to obtain a frequency domain response signal; a modulo module, which is used to perform a modulo operation on the frequency domain response signal to obtain a spectrum amplitude value of a spatial electromagnetic signal; and a data preprocessing module, which is used to compress the frequency domain response signal and send it to an external device through the output interface.

2. The miniaturized electromagnetic sensor according to claim 1, characterized in that: The radio frequency transceiver uses the AD9361 integrated transceiver chip, and the processor uses the ZYNQ7020 series AP-SOC chip.

3. The miniaturized electromagnetic sensor according to claim 2, characterized in that: The SPI interface derived from the processor is connected to the SPI control interface of AD9361 for configuring the parameters of AD9361.

4. The miniaturized electromagnetic sensor according to claim 3, characterized in that: The processor is externally connected to a 2000MB DDR chip and is also provided with an SD card interface; The baseband data interface of AD9361 is connected to the PL end of the processor. The processor sends the received baseband digital signal to the DDR chip through the AXI bus connected to the internal AXI-DMA through timing matching and control.

5. The miniaturized electromagnetic sensor according to any one of claims 1 to 4, characterized in that: The broadband antenna includes a loop antenna for sensing low-frequency space electromagnetic signals and a conical antenna for sensing high-frequency space electromagnetic signals.

6. The miniaturized electromagnetic sensor according to claim 5, characterized in that: It also includes a housing, wherein a plurality of antenna interfaces are disposed on the housing, and the broadband antenna is pluggably disposed in the antenna interface; The radio frequency front-end module and the intermediate frequency processing module are arranged in the shell, and the output interface is embedded in the shell.

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