Miniaturized wireless self-powered alternating current electric field measurement method and system

Abstract

The invention relates to the technical field of power grid measurement, in particular to a miniaturized wireless self-powered alternating current electric field measurement method and system. Comprising the following steps: acquiring radio frequency energy in an electric field environment, and converting the radio frequency energy into direct current electric energy through a radio frequency energy acquisition system consisting of a microstrip antenna, a voltage doubling rectifying circuit and an energy management circuit; an alternating current electric field signal is collected through a differential dual-electrode sensor structure, and an electric field voltage signal is generated; amplifying the voltage signal through an instrument amplifier, and obtaining a digital signal of the electric field signal through an analog-to-digital conversion circuit; and processing and analyzing the alternating current electric field information according to the digital signal. By combining a radio frequency energy acquisition technology with a differential dual-electrode sensing structure, the electric field sensor has the performance characteristics of self energy supply, miniaturization, high precision, wide frequency response and low power consumption. The system can measure various types of electric field signals, including sine wave, triangular wave and square wave electric field signals, has a wide frequency range and a wide measuring range, and is excellent in linearity.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid measurement, and in particular to a miniaturized wireless self-powered AC electric field measurement method and system. Background Art

[0002] With the rise and rapid development of the power Internet of Things (IoT) and big data, smart grids are shifting towards information-based perception and intelligent analysis based on massive amounts of data. As the primary development model for future power grids, the development of smart grids relies on the support of a large number of widely distributed intelligent sensor nodes. As one of the most critical physical quantities in power systems, the electric field represents the operating status of the grid and contains information about the operation of electrical equipment. Therefore, accurate monitoring of this information is essential.

[0003] As a crucial component of smart grids, sensor technology, with its advantages of miniaturization, digitization, intelligence, strong stability, and low power consumption, underpins the ubiquitous sensing capabilities of smart grids. However, efficiently and reliably harvesting energy from the environment and converting it into sufficient, continuous power to power sensors remains a key challenge in smart grids.

[0004] Currently, the most common way to power sensors is with batteries. However, batteries have limited lifespans and require regular replacement and recharging. Furthermore, their relatively large size hinders sensor integration and robustness. Furthermore, with the proliferation of sensor devices, a large number of discarded batteries contributes to environmental pollution and hinders sustainable development. Battery-free wireless technologies based on energy harvesting are a key solution. They can collect wireless energy from the surrounding environment and convert it into direct energy, providing sufficient power for low-power IoT devices.

[0005] Traditional electric field sensors, such as dipole antennas and spherical sensors, contain a high level of metal, significantly distorting the original electric field, leading to reduced measurement accuracy and poor anti-interference capabilities. In recent years, newer electric field sensors have emerged, including those based on the electro-optical effect, MEMS, and the inverse piezoelectric effect. However, each has its own challenges, including poor temperature stability, high cost, inability to measure higher frequencies, and limited sensitivity.

[0006] Currently, electric field sensors in smart grids are still powered by batteries and magnetic rings, with no alternatives utilizing radio frequency (RF) energy. Furthermore, electric field measurements require sensors with high performance, including miniaturization, minimal distortion, wideband response, high precision, and low power consumption. Therefore, developing a miniaturized, wireless, self-powered AC electric field sensing system that can effectively utilize ambient RF energy is crucial. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the problem to be solved by the present invention is how to solve the problem that electric field sensors are still powered by batteries and magnetic rings, and are not yet powered by radio frequency energy. At the same time, electric field measurement also requires the sensor to have high performance characteristics such as miniaturization, small distortion, wide frequency response, high precision, and low power consumption.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0010] In a first aspect, an embodiment of the present invention provides a miniaturized wireless self-powered AC electric field measurement method, which includes acquiring radio frequency energy in an electric field environment and converting the radio frequency energy into direct current power through a radio frequency energy collection system consisting of a microstrip antenna, a voltage doubling rectifier circuit, and an energy management circuit;

[0011] The AC electric field signal is collected through a differential dual-electrode sensor structure to generate an electric field voltage signal;

[0012] The voltage signal is amplified by an instrumentation amplifier, and a digital signal of the electric field signal is obtained by an analog-to-digital conversion circuit;

[0013] Process and analyze AC electric field information based on digital signals.

[0014] As a preferred solution of the miniaturized wireless self-powered AC electric field measurement method of the present invention, the radio frequency energy collection system includes:

[0015] A single microstrip antenna is composed of a dielectric substrate, a radiator and a ground plane;

[0016] The voltage doubler rectifier circuit uses a double-branch stub structure for impedance matching to convert the collected RF energy into DC power;

[0017] The energy management circuit is designed with the BQ25570 chip as the core and uses supercapacitors as energy storage elements to store and release electrical energy.

[0018] As a preferred solution of the miniaturized wireless self-powered AC electric field measurement method of the present invention, the structure of the single microstrip antenna includes:

[0019] The thin metal layer at the bottom of the substrate is connected to the ground plane, and the front side is made into a radiator of a specific shape using a photolithography process;

[0020] The radio frequency energy is transmitted to the antenna through the feeder, generating an electromagnetic signal between the patch and the ground plane, which is radiated through the gap between the ground plane and the patch.

[0021] As a preferred solution of the miniaturized wireless self-powered AC electric field measurement method of the present invention, the differential dual-electrode sensor structure comprises:

[0022] A pair of electrodes is set up, an electric field is formed between the electrodes, and a suspended potential difference is generated as the input of the measurement system;

[0023] The electric field voltage signals between the electrodes are in direct proportion and no subsequent integration circuit is required.

[0024] As a preferred solution of the miniaturized wireless self-powered AC electric field measurement method described in the present invention, the AC electric field signal includes a sinusoidal wave electric field signal, a triangular wave electric field signal and a square wave electric field signal, and the operating frequency range is 10Hz to 100kHz.

[0025] As a preferred solution of the miniaturized wireless self-powered AC electric field measurement method described in the present invention, the frequency range of the measured electric field information is 10Hz to 100kHz, and the measurement range is 0.5kV / m to 10kV / cm.

[0026] As a preferred solution of the miniaturized wireless self-powered AC electric field measurement method of the present invention, it also includes: measuring the lightning field by using different types of instrument amplifiers, wherein the instrument amplifiers include AD8226 instrument amplifier and AD8421 instrument amplifier.

[0027] In a second aspect, an embodiment of the present invention provides a miniaturized wireless self-powered AC electric field measurement system, which includes a radio frequency energy acquisition module for acquiring radio frequency energy in an electric field environment and converting the radio frequency energy into direct current power through a microstrip antenna, a voltage doubling rectifier circuit, and an energy management circuit;

[0028] An electric field sensing module is used to collect AC electric field signals through a differential dual-electrode sensor structure and generate electric field voltage signals;

[0029] A signal processing module is used to amplify the voltage signal through an instrumentation amplifier and obtain a digital signal of the electric field signal through an analog-to-digital conversion circuit;

[0030] The data analysis module is used to process and analyze AC electric field information based on digital signals.

[0031] In a third aspect, an embodiment of the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, the steps of the miniaturized wireless self-powered AC electric field measurement method as described in the first aspect of the present invention are implemented.

[0032] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of the miniaturized wireless self-powered AC electric field measurement method as described in the first aspect of the present invention are implemented.

[0033] The beneficial effects of the present invention are as follows: by combining radio frequency energy harvesting technology with a differential dual-electrode sensing structure, the invention achieves the performance characteristics of the electric field sensor, such as self-power, miniaturization, high precision, wide-band response, and low power consumption. Compared with the existing technology, this method not only solves the problems of traditional electric field sensors such as large size, large distortion, and the need for regular battery replacement, but also optimizes the entire process from electric field measurement to signal processing, significantly improving the overall performance of the measurement system. This innovative electric field measurement solution provides an effective tool for accurate monitoring of electric field information in smart grids, is of great significance to promoting grid operation status monitoring and equipment health management, and lays a technical foundation for the application of power Internet of Things and big data technology in smart grids. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative work.

[0035] Figure 1 A flow chart of a miniaturized wireless self-powered AC electric field measurement method;

[0036] Figure 2 A diagram of a computer device for miniaturized wireless self-powered AC electric field measurement method;

[0037] Figure 3 A photo of a microstrip antenna for miniaturized wireless self-powered AC electric field measurement.

[0038] Figure 4 A diagram of a voltage-doubling rectifier circuit for miniaturized wireless self-powered AC electric field measurement.

[0039] Figure 5 A diagram of the energy management circuit for the miniaturized wireless self-powered AC electric field measurement method;

[0040] Figure 6 The hardware circuit structure diagram of the differential two-electrode electric field sensor for miniaturized wireless self-powered AC electric field measurement method;

[0041] Figure 7 A photo of a differential two-electrode electric field sensor for miniaturized wireless self-powered AC electric field measurement.

[0042] Figure 8 A line graph showing the output characteristics of a radio frequency energy harvester for a miniaturized wireless self-powered AC electric field measurement method;

[0043] Figure 9 This is a test diagram of the frequency response characteristics of the electric field sensor for the miniaturized wireless self-powered AC electric field measurement method;

[0044] Figure 10 Output linearity test diagram of the electric field sensor for the miniaturized wireless self-powered AC electric field measurement method;

[0045] Figure 11 This is a common waveform test fitting diagram of the electric field sensor for the miniaturized wireless self-powered AC electric field measurement method;

[0046] Figure 12 This is a lightning current waveform test diagram of the electric field sensor for the miniaturized wireless self-powered AC electric field measurement method. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0048] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0049] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it constitute a separate or selective embodiment that is mutually exclusive with other embodiments.

[0050] Example 1

[0051] Reference Figures 1 to 12 , which is the first embodiment of the present invention, provides a miniaturized wireless self-powered AC electric field measurement method, comprising:

[0052] S100: Acquires radio frequency energy in the electric field environment and converts it into direct current energy through an RF energy harvesting system consisting of a microstrip antenna, a voltage-doubling rectifier circuit, and an energy management circuit.

[0053] In this embodiment, the RF energy harvesting system uses a high-efficiency microstrip antenna array to receive RF signals from the environment and convert them into usable electrical energy. The harvesting system operates in the ISM band near 2.4 GHz, a frequency band commonly used for wireless communications and energy transmission. The relatively high energy density of electromagnetic waves facilitates energy harvesting. The microstrip antenna uses FR-4 as its substrate, with a thickness of 1.6 mm, a relative dielectric constant of 4.4, and a loss tangent of 0.02. By optimizing the antenna's structural parameters, it achieves high reception efficiency and good impedance matching in the target frequency band.

[0054] In an optional embodiment, the receiving frequency range of the microstrip antenna can be expanded to 900MHz-3GHz to accommodate the needs of RF energy collection in different frequency bands. For example, in urban environments, the signal energy generated by mobile communication networks is relatively abundant, and 900MHz GSM signals, 1.8GHz DCS signals, 2.1GHz WCDMA signals, and 2.4GHz Wi-Fi signals can be collected simultaneously, thereby improving the overall efficiency of energy collection. The antenna array design can adopt a variety of structures, such as circularly polarized patch antennas, T-shaped patch antennas, or improved F-shaped antennas. Each structure has its own specific advantages, and the best solution can be selected based on the actual application scenario.

[0055] In another optional embodiment, the microstrip antenna design can adopt a multi-band resonant structure, and multi-frequency resonance characteristics can be achieved by introducing parasitic units or slotted structures on the basic resonant unit. This design can capture electromagnetic energy in multiple frequency bands simultaneously, greatly improving energy collection efficiency. For example, a dual-frequency resonance characteristic can be formed by opening a U-shaped slot on a rectangular patch antenna; or a planar interwoven multi-frequency structure can be used to ensure that the antenna has good matching characteristics in different frequency bands. In addition, broadband design techniques can be used, such as introducing trapezoidal wedges, adjusting the substrate thickness, or using a multi-layer structure, so that the antenna can maintain good reception performance over a wide frequency range.

[0056] It should be noted that the design of the microstrip antenna directly affects the efficiency of the energy harvesting system. To maximize energy harvesting efficiency, the antenna's impedance characteristics need to match those of the subsequent voltage doubler and rectifier circuit. By adjusting parameters such as the antenna structure, feed position, and grounding method, the antenna's input impedance can be optimized to approach that of the voltage doubler and rectifier circuit, thereby reducing reflection losses during energy transmission. At the same time, the antenna's radiation directivity also needs to be optimized based on the actual application scenario. For example, for sensors placed around power equipment, the antenna's direction should be toward the direction with the most energy to maximize energy harvesting efficiency.

[0057] S101: The RF energy harvesting system includes:

[0058] A single microstrip antenna is composed of a dielectric substrate, a radiator and a ground plane;

[0059] In this embodiment, the single-unit microstrip antenna utilizes a standard microstrip structure, consisting of a dielectric substrate, a patch radiator, and a ground plane. The dielectric substrate is made of FR-4 material, 1.6 mm thick, with a relative dielectric constant of 4.4 and a loss tangent of 0.02. The top surface of the substrate is photoetched into a specifically shaped radiator, while the bottom surface is a fully metallized layer that serves as the ground plane. The radiator is rectangular, measuring 40 mm x 30 mm, and is designed based on the operating frequency. The radiator is connected to the RF input via a microstrip feeder line. The feeder line is 2 mm wide and 15 mm long, and its position is optimized for good impedance matching.

[0060] In an optional embodiment, a dielectric substrate made of other materials can be used, such as a polytetrafluoroethylene (PTFE) substrate, which has a relative dielectric constant of approximately 2.2 and a loss tangent of approximately 0.001. Compared with FR-4 material, it has lower loss and can improve antenna efficiency, but the cost is higher. In addition, the shape of the radiator can also be designed in a variety of ways, such as circular, elliptical, triangular, or irregular shapes. Each shape has its own specific radiation characteristics and impedance characteristics, and the most suitable shape can be selected according to actual needs. For example, a circular patch antenna can achieve good circular polarization radiation characteristics and has good reception capabilities for electromagnetic waves in different directions.

[0061] In another optional embodiment, improvements to the basic microstrip structure can be introduced, such as a defected ground plane (DGS), electromagnetic bandgap (EBG), or slotted structure, to improve the antenna's bandwidth, efficiency, or size. For example, introducing a DGS structure on the ground plane can effectively increase the antenna's bandwidth; creating appropriate slots in the patch radiator can achieve antenna miniaturization or multi-frequency characteristics; and employing an EBG structure can suppress surface waves and improve the antenna's radiation efficiency. These improvements can be selected and combined based on actual application needs and system performance requirements.

[0062] It should be noted that the design of a single microstrip antenna requires a balance of multiple performance indicators, including resonant frequency, bandwidth, gain, radiation directivity, and impedance matching. In actual design, electromagnetic simulation software (such as HFSS, CST, or ADS) can be used to optimize parameters to achieve optimal antenna performance in the target frequency band. Furthermore, the antenna's fabrication process requires strict control, including photolithography accuracy, substrate material consistency, and soldering quality, to ensure that the actual antenna is consistent with the simulated design and achieves the expected performance.

[0063] The voltage doubler rectifier circuit uses a double-branch stub structure for impedance matching to convert the collected RF energy into DC power;

[0064] In this embodiment, an optimized voltage doubler rectifier circuit design is adopted to improve the RF-DC conversion efficiency. The circuit is based on the Dickson voltage doubler structure and uses the HSMS-2850 Schottky diode as the rectifier element. This diode has low forward voltage drop and low parasitic capacitance characteristics, making it suitable for RF rectification. The rectifier circuit adopts a 4-stage Dickson structure, which can convert the input RF signal into approximately 4 times the DC voltage. In order to solve the impedance matching problem in the RF circuit, a double-branch stub structure is specially designed. By precisely controlling the length and width of the two stubs, good impedance matching in the target frequency band is achieved.

[0065] In an optional embodiment, the number of rectifier stages can be adjusted based on the required output voltage. For example, when a higher output voltage is required, the number of rectifier stages can be increased to 6 or 8; when the input RF signal strength is high, the number of stages can be reduced to 2 to simplify the circuit structure. Furthermore, the choice of rectifier diode can be adjusted based on different application requirements. For example, the SMS7630 diode has better rectification efficiency at low input power and is suitable for weak signal environments; while the BAT15-03W diode has a higher breakdown voltage and is suitable for high input power applications.

[0066] In another optional embodiment, the matching network of the voltage doubler rectifier circuit may also adopt other structures, such as an L-type network, a T-type network, or a π-type network. Each matching network has its own characteristics and scope of application. For example, the L-type network has a simple structure but a narrow matching bandwidth; the T-type network and the π-type network have more complex structures but can achieve a wider matching bandwidth and more accurate impedance transformation. In practical applications, the most appropriate matching network structure can be selected based on the balance between system requirements and circuit complexity. In addition, adaptive matching technology can be used to dynamically adjust the matching network parameters through variable capacitors or switching circuits to adapt to impedance matching requirements under different working conditions.

[0067] It should be noted that the design of a voltage-doubling rectifier circuit requires comprehensive consideration of multiple factors, including input RF power, operating frequency, output voltage requirements, and load characteristics. In actual design, circuit parameters must be optimized through simulation and testing, including diode model selection, capacitor value setting, and matching network design. Furthermore, the rectifier circuit layout must consider RF characteristics to minimize the impact of parasitic effects and improve rectification efficiency. Furthermore, factors such as the rectifier circuit's operating temperature range, durability, and cost also need to be weighed in practical applications.

[0068] The energy management circuit is designed with the BQ25570 chip as the core and uses supercapacitors as energy storage elements to store and release electrical energy.

[0069] In this embodiment, the energy management circuit uses the BQ25570 chip from Texas Instruments as its core. This chip is an ultra-low power boost converter designed specifically for energy harvesting applications and has high-efficiency power management functions. The circuit includes a boost conversion part and a battery charging management part. The boost converter has a starting voltage as low as 330mV and an operating voltage range of 100mV to 5.5V, which can effectively handle the low voltage output by the rectifier circuit. The circuit uses maximum power point tracking (MPPT) technology to automatically adjust the operating point so that the energy harvesting system always operates at optimal efficiency. As an energy storage element, a 1F / 5.5V supercapacitor is selected, which has high energy density, long cycle life and excellent temperature characteristics.

[0070] In an optional embodiment, the energy storage element can select supercapacitors of different specifications according to the actual application requirements. For example, when energy storage is required for a longer period of time, a supercapacitor with a larger capacity, such as 5F or 10F, can be selected; when the system has strict restrictions on volume, a supercapacitor with a small capacity but high energy density can be selected. In addition, the energy storage solution can also consider the use of thin-film batteries or lithium-ion batteries, which have higher energy density but relatively few charge and discharge cycles. In some special application scenarios, a hybrid energy storage strategy can also be adopted, such as using supercapacitors and lithium batteries in parallel. The supercapacitor is responsible for handling short-term high-power demands, and the lithium battery provides long-term energy support.

[0071] In another optional embodiment, the energy management chip can also be replaced according to system requirements, such as Linear Technology's LTC3108 or LTC3588. These chips also have low startup voltage and high-efficiency energy management functions, but differ in input range, output stability, and control flexibility. For example, the LTC3108 is suitable for lower voltage input scenarios, with a startup voltage as low as 20mV; while the LTC3588 is more suitable for piezoelectric energy harvesting applications. In addition, the energy management circuit can also add more control and protection functions, such as overvoltage protection, overcurrent protection, temperature monitoring, etc., to improve system reliability and safety.

[0072] It should be noted that the design of energy management circuits requires comprehensive consideration of factors such as energy input characteristics, load requirements, and system reliability. In actual design, energy balance analysis under different operating conditions is necessary to ensure stable system operation in various scenarios. Furthermore, energy management strategies must be optimized based on the application scenario. For example, system performance can be improved when energy is sufficient, while low-power mode can be used to extend operating time when energy is insufficient. Furthermore, factors such as the efficiency, startup characteristics, and stability of the energy management circuit require detailed testing and verification in actual applications to ensure that the overall system performance meets design requirements.

[0073] S102: The structure of a single microstrip antenna includes:

[0074] The thin metal layer at the bottom of the substrate is connected to the ground plane, and the front side is made into a radiator of a specific shape using a photolithography process;

[0075] In this embodiment, the microstrip antenna is manufactured using a standard PCB process. The substrate is made of 1.6mm thick FR-4 material, clad on both sides with 35μm copper. The entire copper layer on the bottom of the substrate is retained as a ground plane, and the top is precision photolithography-fabricated to create a specifically shaped radiator. The specific process includes: substrate pretreatment, including cleaning and surface activation; then, application of photoresist and pre-baking; followed by photolithography exposure using a pre-designed mask pattern; post-exposure development to remove unexposed photoresist; then, etching to remove the unwanted copper layer; finally, removal of the remaining photoresist and surface treatment, such as tinning or spray coating, to prevent oxidation of the copper layer.

[0076] In an optional embodiment, the substrate material can be made of high-frequency board with better performance, such as RogersRO4350B, which has a lower loss tangent (about 0.0031) and a more stable dielectric constant (about 3.48), which can improve the radiation efficiency of the antenna and reduce signal loss. At the same time, the thickness of the copper layer can also be adjusted as needed. For example, when higher conductivity is required, a thicker copper layer such as 70μm or 105μm can be selected; when higher requirements are placed on precision lines, a thinner copper layer such as 17.5μm can be selected. In addition, the surface treatment method can also be diversified, such as using financial composite board (ENIG), immersion gold (Immersion Gold) or organic solderability protective layer (OSP), etc. Each surface treatment method has its specific advantages and applicable scenarios.

[0077] In another alternative embodiment, the microstrip antenna can be fabricated using more advanced manufacturing processes. For example, laser direct writing technology can replace traditional photolithography to achieve higher processing precision and more complex pattern structures. Alternatively, 3D printing technology combined with metallization can be used to produce antennas with unique three-dimensional structures. Furthermore, the use of multi-layer PCB technology can be considered to integrate the antenna with other circuits on the same substrate. For example, the feed line can be designed into the substrate, or other RF circuits can be integrated into the bottom layer, thereby improving the system's integration and reliability.

[0078] It should be noted that the manufacturing process and material selection of microstrip antennas directly impact the antenna's performance and consistency. In actual production, strict control of process parameters, including exposure time, development time, and etching rate, is required to ensure the final antenna has the correct size and shape. Furthermore, mass-produced antennas require rigorous quality control and testing, including visual inspection, impedance measurement, and radiation characteristics testing, to ensure product consistency and performance stability. Furthermore, the impact of manufacturing tolerances must be considered during the design phase. Simulation analysis can be used to assess the impact of tolerances on antenna performance, and design parameters can be adjusted as necessary to improve process adaptability and product yield.

[0079] The radio frequency energy is transmitted to the antenna through the feeder, generating an electromagnetic signal between the patch and the ground plane, which is radiated through the gap between the ground plane and the patch.

[0080] In this embodiment, the feeding structure of the microstrip antenna adopts a direct microstrip line feeding method. The feed line width is 2 mm and the impedance is about 50 ohms, which matches the standard RF interface. The feed line length is optimized to reduce reflection loss. When the RF energy is transmitted to the antenna radiator through the feed line, a standing wave electric field distribution is formed between the radiator and the ground plane. The radiation mechanism of the microstrip antenna is the gap radiation at the edge of the patch. The main radiation direction is perpendicular to the substrate, and the radiation polarization direction is consistent with the electric field direction inside the antenna. The operating frequency of the antenna is mainly determined by the patch size. Usually, the patch length is about half a wavelength (considering the effective dielectric constant).

[0081] In an optional embodiment, the feeding method can adopt other structures, such as probe feeding, slot coupling feeding or coplanar waveguide feeding. Each feeding method has its own characteristics and advantages. For example, probe feeding can provide a wider impedance matching bandwidth; slot coupling feeding can effectively isolate DC, which is convenient for integration with subsequent circuits; coplanar waveguide feeding is convenient for integration with single-layer circuit boards. In addition, the position of the feeding point can also be adjusted as needed, such as edge feeding, inward feeding or diagonal feeding. Different feeding positions will result in different impedance characteristics and radiation patterns. For example, when the feeding point is at the edge of the patch, the input impedance is high; when the feeding point moves toward the center, the impedance gradually decreases, and impedance matching can be achieved by adjusting the position of the feeding point.

[0082] In an alternative embodiment, more complex antenna structures can be employed to improve performance, such as by introducing parasitic elements, slotted structures, or defective ground planes. For example, adding parasitic patches around the main radiator can broaden the antenna bandwidth or enable multi-frequency operation; creating appropriately shaped slots in the radiator can adjust the antenna's resonant frequency and impedance characteristics; and introducing defective structures in the ground plane can suppress surface waves and improve radiation efficiency. Furthermore, multilayer designs, such as stacked patch antennas or embedded feed structures, can provide greater design freedom and enable more complex functionality.

[0083] It should be noted that the design of microstrip antennas requires consideration of the interplay of multiple factors, including patch size, substrate material, feed method, and matching network. In actual design, electromagnetic simulation software can be used to perform parameter sweeps and optimization to find the optimal combination of design parameters. At the same time, it is important to note the inherent limitations of microstrip antennas, such as their narrow bandwidth and the significant impact of substrate losses on radiation efficiency, and to implement appropriate improvements in the application. Furthermore, in actual application environments, the impact of surrounding objects on antenna performance, such as metal objects, dielectric materials, and the human body, must also be considered. These factors can cause variations in antenna performance and need to be accounted for in design and testing.

[0084] S200: collecting AC electric field signals through a differential dual-electrode sensor structure to generate electric field voltage signals;

[0085] In this embodiment, the electric field sensor utilizes an improved differential dual-electrode structure, effectively overcoming the limitations of traditional single-electrode D-dot sensors. The sensor consists of two opposing copper electrodes measuring 10 mm x 10 mm, separated by 20 mm. The electrode surfaces are polished to reduce electric field distortion caused by surface irregularities. When the sensor is exposed to an AC electric field, a potential difference is generated between the two electrodes. This potential difference is proportional to the external electric field strength. This potential difference is captured by a high-impedance preamplifier, directly generating a voltage signal proportional to the electric field without the need for subsequent integration.

[0086] In an optional embodiment, the shape and size of the electrodes can be optimized according to application requirements. For example, when it is necessary to measure the electric field distribution in a smaller area, smaller electrodes, such as 5mm×5mm or smaller, can be used; when higher sensitivity is required, the electrode area can be increased or the electrode spacing can be reduced. Electrode materials can also be selected according to needs. For example, when used in a corrosive environment, corrosion-resistant stainless steel or titanium alloy can be selected; when higher conductivity is required, materials such as silver or gold can be selected. In addition, the electrode surface can also be treated using different processes, such as gold plating, silver plating, or other surface coatings, to improve surface conductivity and durability.

[0087] In another optional embodiment, the differential dual-electrode structure can be further improved, such as using a three-electrode or multi-electrode structure to achieve the measurement of the electric field direction or the electric field gradient. For example, by arranging multiple electrode pairs in three-dimensional space, the electric field components in three directions can be measured simultaneously, thereby obtaining vector information of the electric field; or by arranging multiple electrode pairs at different positions, the spatial distribution and gradient information of the electric field can be measured. In addition, the geometric configuration of the electrodes can also be considered, such as parallel plate electrodes, coaxial electrodes, or spherical electrodes. Different geometric configurations are suitable for different measurement scenarios and requirements.

[0088] It should be noted that the design of a differential two-electrode sensor requires comprehensive consideration of factors such as sensitivity, linearity, frequency response, and spatial resolution. In practical design, theoretical analysis and electric field simulation are required to optimize the geometric parameters of the electrodes to achieve optimal measurement performance. The sensor's equivalent circuit model also needs to be considered, including the distributed capacitance between the electrodes, capacitance to ground, and parasitic inductance, as these parameters affect the sensor's frequency response characteristics. Furthermore, the sensor's mounting and support structure require careful design to minimize the impact of the supporting material and the surrounding environment on the electric field distribution, ensuring measurement accuracy and consistency. When used in high-voltage or strong electric field environments, the electrode's breakdown protection and insulation performance must also be considered to ensure the sensor's safe and reliable operation.

[0089] S201: The differential dual-electrode sensor structure comprises:

[0090] A pair of electrodes is set up, an electric field is formed between the electrodes, and a suspended potential difference is generated as the input of the measurement system;

[0091] In this embodiment, the core of the differential dual-electrode sensor is a pair of carefully designed metal electrodes. The electrodes are made of high-purity copper with a purity greater than 99.9% to ensure good electrical conductivity. The electrode dimensions are 10mm × 10mm × 1mm, and the surface is precision polished to a roughness of less than 1μm to reduce the impact of surface irregularities on the electric field distribution. The two electrodes are placed in parallel with a spacing of 20mm and supported and fixed by a highly insulating material (polytetrafluoroethylene) to ensure that there is no conductive path between the electrodes. When the sensor is placed in an external AC electric field, the electric field lines pass through the two electrodes, inducing charges on the electrode surfaces, forming a potential difference proportional to the external electric field. This floating potential difference is independent of the ground reference and has good anti-interference capabilities.

[0092] In an optional embodiment, the geometry of the electrode can be optimized to improve the measurement performance in a specific application scenario. For example, a circular electrode with a diameter of 10 mm can be used to reduce edge effects; or a spherical electrode with a diameter of 5 mm can be used to achieve more uniform field induction. The support structure of the electrode can also be improved as needed, such as using a herringbone support structure to reduce the influence of the support material on the electric field; or using a cantilever beam structure to set the support point on the periphery of the electrode to reduce the distortion of the electric field by the support. In addition, the surface treatment of the electrode can also use different processes, such as electrochemical polishing, plasma cleaning or surface coating, to improve the surface quality and stability.

[0093] In another optional embodiment, the electrode pairs can be arranged in different ways, such as vertically, obliquely, or coaxially, to accommodate different measurement requirements. For example, when measuring the horizontal electric field, a horizontally arranged electrode pair can be used; when measuring the vertical electric field, a vertically arranged electrode pair can be used; when measuring electric field components in multiple directions simultaneously, multiple sets of electrode pairs arranged in different directions can be used. In addition, the size ratio of the electrodes can also be considered. When the two electrodes are of different sizes, an asymmetric sensing characteristic will be formed, which can be used for the measurement requirements of specific scenarios.

[0094] It should be noted that the design of a differential two-electrode sensor requires consideration of multiple factors, including electrode material, shape, size, surface treatment, support structure, and relative position. In practical design, these parameters must be optimized through electric field theory analysis and finite element simulation to achieve optimal measurement performance. The sensor's equivalent circuit model must also be considered, including the electrode's intrinsic capacitance, the mutual capacitance between electrodes, and the coupling capacitance with the surrounding environment. These parameters affect the sensor's frequency response and sensitivity characteristics. Furthermore, the sensor's shielding and grounding require careful design to minimize the impact of external electromagnetic interference on the measurement and improve the signal-to-noise ratio and stability of the measurement. When used in high-voltage or high-field environments, the electrode's breakdown resistance and long-term stability must also be considered to ensure safe and reliable sensor operation.

[0095] The electric field voltage signals between the electrodes are in direct proportion and no subsequent integration circuit is required.

[0096] In this embodiment, the working principle of the differential two-electrode sensor is based on the electric field induction effect. When two electrodes are placed in an AC electric field, the electric field induces charges on the surfaces of the two electrodes, forming a potential difference. According to electromagnetic field theory, this potential difference is directly proportional to the external electric field strength, that is, V = k 〃 E, where V is the measured voltage, E is the external electric field strength, and k is the proportional coefficient of the sensor (in meters), which is determined by the electrode size and spacing. This direct proportional relationship eliminates the need for integration of the sensor output signal, greatly simplifies the signal processing circuit, and reduces the error introduced by the integrator. Experimental measurements of the sensor show that in the frequency range of 10Hz to 100kHz, the ratio of the output signal to the actual electric field signal remains near 0dB, indicating good linearity.

[0097] In an optional embodiment, the sensitivity coefficient k of the sensor can be optimized by adjusting the electrode parameters. For example, when the electrode spacing is increased, the sensitivity coefficient k will increase, and the measured voltage V will also increase accordingly, which is conducive to improving the measurement accuracy of weak electric fields; but at the same time, a larger spacing may also lead to a decrease in spatial resolution. Therefore, a balance can be made between sensitivity and spatial resolution according to actual application requirements. In addition, the shape and area of ​​the electrode will also affect the sensitivity coefficient. For example, when the electrode area is increased, the induced charge increases, more electric field energy can be collected, and the signal-to-noise ratio can be improved; but at the same time, an overly large electrode may also interfere with the original electric field distribution. In the design, the optimal electrode parameter combination can be found through electromagnetic field simulation and experimental testing.

[0098] In another optional embodiment, the sensor's electrical structure can be further improved to optimize signal transmission and processing. For example, an impedance matching network can be designed between the electrodes and the signal processing circuit to reduce reflection and loss during signal transmission; or balanced transmission lines can be used to transmit the electrode signals to a differential amplifier to reduce common-mode interference. Furthermore, consideration can be given to integrating an amplifier circuit at the sensor front end to amplify weak electrode signals directly near the sensor, improving the signal's anti-interference capability. In some high-precision applications, temperature compensation circuits can also be considered to reduce the impact of ambient temperature changes on measurement results.

[0099] It should be noted that the linear proportional relationship of differential dual-electrode sensors is their key advantage, effectively avoiding the complex integral calculations required by traditional D-dot sensors. However, in practical applications, several factors must be considered, such as the non-ideal characteristics of the electrode surface, the dielectric properties of the supporting material, and interference from surrounding objects, which can affect this linear relationship. These factors can cause the actual proportionality coefficient to deviate from the theoretical value or exhibit slight nonlinear characteristics at different frequencies and field strengths. Therefore, before practical application, the sensor must be precisely calibrated to establish an accurate conversion relationship. Furthermore, in high-frequency applications, the influence of transmission line effects and distributed parameters must be considered to ensure that the sensor maintains a good linear response throughout the entire operating frequency range.

[0100] S202: The AC electric field signal includes a sine wave electric field signal, a triangle wave electric field signal, and a square wave electric field signal, and the operating frequency range is 10 Hz to 100 kHz.

[0101] In this embodiment, the differential two-electrode sensor is designed to detect AC electric field signals of various waveforms, including sine wave, triangle wave and square wave electric field signals. The operating frequency range of the sensor covers 10Hz to 100kHz, which meets the application requirements of most industries and power systems. In the low-frequency region (less than 10kHz), the sensor has excellent tracking performance for all waveforms, and the phase difference and amplitude deviation between the output waveform and the input electric field waveform are extremely small. In the medium-frequency region (10kHz to 50kHz), the sensor still maintains good linearity, but the edge of the square wave signal will be slightly distorted, which is caused by the attenuation of the high-frequency harmonic components. In the high-frequency region (50kHz to 100kHz), the sensor maintains a good response to the sine wave, but there is a certain attenuation of the high-frequency components of the square wave and triangle wave, especially the edge of the square wave signal will show more obvious oscillation and delay.

[0102] In an optional embodiment, the operating frequency range and high-frequency characteristics of the sensor can be expanded by optimizing the front-end circuit design. For example, a higher-bandwidth preamplifier, such as an instrumentation amplifier with a bandwidth of 1 MHz, can be used; or the transmission line design between the electrode and the amplifier circuit can be optimized to reduce the loss and distortion of high-frequency signals. For applications that pay special attention to high-frequency performance, a compensation network can be used, such as introducing resonant compensation or a high-pass filter in the front-end circuit to improve the response in the high-frequency band. In addition, digital signal processing techniques, such as inverse filtering or deconvolution algorithms, can be used to restore high-frequency components at the software level, further improving the frequency response characteristics of the system.

[0103] In another optional embodiment, the frequency response characteristics of the sensor can be customized according to different application scenarios and measurement requirements. For example, when primarily measuring power frequency (50 / 60Hz) electric fields, the sensor's performance near this frequency can be optimized to enhance anti-interference capabilities. When measuring pulsed electric fields containing a large amount of high-frequency components, the sensor's high-frequency response can be optimized to ensure accurate edge capture. For applications that require simultaneous measurement of electric fields in different frequency bands, a multi-channel system can be designed, with each channel optimized for a specific frequency range, and then the results can be comprehensively analyzed using data fusion technology.

[0104] It should be noted that the waveform and frequency characteristics of the AC electric field signal have a significant impact on the sensor's measurement performance. The sensor's frequency response is primarily limited by factors such as the RC network formed by the distributed capacitance and equivalent resistance of the electrodes, the bandwidth of the preamplifier, the frequency characteristics of the transmission line, and the response speed of the signal processing circuit. In practical designs, these factors must be comprehensively considered, and the sensor's frequency response characteristics must be optimized through theoretical analysis, simulation, and experimental testing. Furthermore, electric field signals of different waveforms contain different spectral components. For example, square waves contain abundant odd harmonic components, and accurate measurement requires a sensor with a wider frequency response range. Therefore, in practical applications, appropriate sensor design and parameter configuration should be selected based on the characteristics of the measured signal, and signal processing compensation should be performed when necessary to obtain the most accurate measurement results.

[0105] S203: The frequency range of the electric field information is 10 Hz to 100 kHz, and the range is 0.5 kV / m to 10 kV / cm.

[0106] In this embodiment, the differential two-electrode sensor's measurement capability covers a wide range of electric field strengths, from weak 0.5kV / m to strong electric fields up to 10kV / cm. This wide range is suitable for a variety of application scenarios, from general industrial environments to strong electric field monitoring around high-voltage power equipment. The sensor maintains a high degree of linearity throughout the entire range, and the output linearity at 50Hz is tested to be R 2 >0.99995, ensuring measurement accuracy. The sensor also boasts a low noise level, with a minimum resolution (i.e., noise-equivalent electric field) of 165V / m / Hz^(1 / 2), enabling accurate measurement of weak electric fields as low as 0.5kV / m. In high-field regions, the sensor exhibits excellent saturation resistance, maintaining accurate measurement performance even in strong electric fields of 10kV / cm, without noticeable distortion or drift.

[0107] In an optional embodiment, the sensor's gain setting can be adjusted to further expand or subdivide its measurement range. For example, for applications requiring the measurement of weaker electric fields, the gain of the front-end amplifier can be increased, and lower-noise amplifier circuits and better shielding measures can be employed to reduce the minimum measurable electric field strength to 0.1 kV / m or even lower. For applications with ultra-high electric field strengths, the gain can be reduced or an appropriate attenuation network designed to extend the maximum measurement range to 15 kV / cm or higher. Furthermore, a circuit that automatically adjusts the gain can be designed, using high gain to improve sensitivity in weak electric fields and automatically switching to low gain to avoid saturation in strong electric fields, thereby achieving a wider dynamic measurement range.

[0108] In another optional embodiment, electric field measurements within different frequency ranges can be optimized. For example, in the low-frequency region (10 Hz to 1 kHz), measurement accuracy can be improved by improving the low-frequency characteristics of the front-end amplifier and reducing 1 / f noise. In the medium-frequency region (1 kHz to 10 kHz), linearity and response speed can be improved by optimizing transmission lines and signal processing circuits. In the high-frequency region (10 kHz to 100 kHz), frequency response characteristics can be improved by reducing electrode size, optimizing transmission paths, and using amplifiers with better high-frequency response. Optimization for specific frequency bands can improve measurement performance within the corresponding frequency range to meet the needs of specific applications.

[0109] It should be noted that a sensor's range and frequency range define its applicable scenarios and measurement capabilities. In practical applications, appropriate sensor configuration and parameter settings must be selected based on the characteristics and requirements of the measurement object. For example, in online monitoring of power equipment, the electric field distribution at the power frequency (50 / 60 Hz) may need to be considered; in electromagnetic compatibility testing of electronic equipment, the electric field characteristics over a wide frequency range may need to be focused on; and in safety monitoring of high-voltage equipment, the presence of discharge precursors under strong electric fields may require attention. Different applications have different requirements for a sensor's range, linearity, response speed, and frequency characteristics, so these factors must be comprehensively considered during sensor design and selection. Furthermore, in actual use, the impact of environmental factors on sensor performance, such as temperature, humidity, and surrounding conductive objects, must be considered. Calibration and compensation should be performed as necessary to ensure the accuracy and reliability of measurement results.

[0110] S300: amplifies the voltage signal through an instrumentation amplifier and obtains a digital signal of the electric field signal through an analog-to-digital conversion circuit;

[0111] In this embodiment, the signal processing circuit uses the high-precision instrumentation amplifier AD8421 as the front-end amplifier circuit. This chip has high common-mode rejection ratio (CMRR>100dB), low noise (9nV / √Hz) and wide bandwidth (10MHz@G=10) characteristics, making it suitable for amplifying weak differential voltage signals. The amplifier gain is set to 10 and is implemented through a precision resistor network. The amplified analog signal is anti-aliased through a low-pass filter with a cutoff frequency set to 200kHz. Subsequently, the analog signal is sent to the 16-bit precision analog-to-digital converter ADS8860 for digitization, with a sampling rate set to 500kSPS to meet the Nyquist sampling theorem requirements. The converted digital signal is transmitted to the subsequent microcontroller via the SPI interface for processing and analysis.

[0112] In an optional embodiment, different instrumentation amplifier models can be selected to suit different application requirements. For example, when lower power consumption is required, the AD8226 instrumentation amplifier can be selected, consuming only approximately 1mW; when higher bandwidth is required, the LTC6363 differential amplifier can be selected, with a bandwidth of up to 800MHz; when extremely low noise is required, the LT1167 instrumentation amplifier can be selected, with an input noise as low as 3.5nV / √Hz. Furthermore, the amplifier gain can be adjusted based on the actual signal strength. For example, for strong signals, a lower gain (e.g., G = 5) can be set to avoid saturation, while for weak signals, a higher gain (e.g., G = 50) can be set to improve the signal-to-noise ratio. The filter cutoff frequency can also be optimized based on the actual signal spectrum characteristics. For low-frequency signals, the cutoff frequency can be lowered to further suppress noise.

[0113] In another optional embodiment, the analog-to-digital conversion portion can adopt different architectures and parameter configurations. For example, when a higher dynamic range is required, a 24-bit Sigma-Delta ADC, such as the ADS1262, can be selected; when a faster sampling rate is required, a pipeline ADC, such as the ADS8476, with a sampling rate of up to 1MSPS, can be selected; when the system requires low power consumption, a successive approximation ADC, such as the ADS7042, with a power consumption of only about 1mW can be selected. In addition, a variable sampling rate mode can be designed, using a high sampling rate when capturing transient events and a low sampling rate during normal monitoring to save energy. For applications that require simultaneous monitoring of multiple frequency bands, a multi-channel parallel sampling system can also be designed, with each channel optimized for a specific frequency band.

[0114] It should be noted that analog signal processing and digital conversion are key components of a measurement system, directly impacting measurement accuracy and reliability. Multiple factors must be considered during design, including signal characteristics (amplitude, frequency range, noise level, etc.), system requirements (accuracy, speed, power consumption, etc.), and environmental conditions (temperature, electromagnetic interference, etc.). The front-end amplifier must have sufficient bandwidth, low noise, and a high common-mode rejection ratio to accurately amplify weak differential signals while suppressing common-mode interference. The low-pass filter must be designed with an appropriate cutoff frequency and roll-off characteristics to suppress high-frequency noise without excessively attenuating the signal's high-frequency components. The analog-to-digital converter must have sufficient resolution and sampling rate to capture signal details and dynamic changes. Furthermore, the signal path layout, shielding, and grounding must be carefully designed to minimize interference and coupling. In practical applications, calibration and compensation techniques are also necessary to eliminate system offset, gain errors, and nonlinearities to improve overall measurement accuracy.

[0115] S301: Also included: measuring the lightning field by using different types of instrumentation amplifiers, including AD8226 instrumentation amplifier and AD8421 instrumentation amplifier.

[0116] To measure fast, transient, and strong electric field signals such as lightning fields, the system is equipped with two different types of instrumentation amplifiers: the AD8226 and the AD8421. The AD8226 is a low-power instrumentation amplifier with a bandwidth of approximately 150kHz at a gain of 10, making it suitable for measuring slowly varying electric fields. The AD8421, on the other hand, is a high-performance instrumentation amplifier with a bandwidth of up to 10MHz at a gain of 10, making it suitable for capturing rapidly varying transient electric fields. A switching circuit allows the system to select between different amplifiers or use both amplifiers in parallel to simultaneously acquire data for comparative analysis. Tests showed that when measuring a standard lightning impulse voltage (1.2 / 50μs), the AD8226 amplifier measured a 4.5μs surge front time, while the AD8421 amplifier measured a 2.62μs surge front time, closer to the actual lightning surge front time (2.08μs).

[0117] In an optional embodiment, the instrumentation amplifier (IA) selection can be expanded to include more types of amplifiers to accommodate electric field measurements with varying characteristics. For example, when extremely low power consumption is required, an ultra-low-power instrumentation amplifier such as the INA333, consuming only 50 μW, can be used. When higher bandwidth is required, a high-speed differential amplifier such as the LTC6409, with a bandwidth of up to 3 GHz, can be used. When measuring extremely strong electric fields, an amplifier with a wide dynamic range such as the LT1997, with a common-mode input range of ±270 V, can be used. Furthermore, a programmable gain amplifier (PGA) circuit can be designed to dynamically adjust the gain through digital control to accommodate electric field signals of varying strengths, eliminating the need for manual switching between different amplifiers.

[0118] S400: Processing and analyzing AC electric field information according to the digital signal.

[0119] In this embodiment, the digital signal processing part uses an STM32F407 microcontroller as the core processing unit, which is equipped with a Cortex-M4 core and a floating-point unit (FPU) with a main frequency of 168MHz, which is suitable for complex real-time signal processing tasks. The processing flow first pre-processes the collected digital signal, including removing DC bias, eliminating trends, and suppressing noise. Then, time domain analysis is performed to extract key parameters such as peak value, effective value, and form factor; at the same time, frequency domain analysis is performed to calculate the signal spectrum using the FFT algorithm, identify the main frequency components, and evaluate the harmonic content. For special waveforms such as lightning fields, wave head analysis is also performed to calculate parameters such as rise time, duration, and peak time. The processing results can be displayed in real time or stored in an SD card, or transmitted to a remote monitoring center via a wireless module (such as LoRa or ZigBee).

[0120] In an optional embodiment, a more advanced digital signal processing algorithm can be introduced to extract more valuable information. For example, the wavelet transform (WT) can be used instead of the traditional Fourier transform to achieve time-frequency joint analysis and better capture the characteristics of non-stationary signals; or the empirical mode decomposition (EMD) algorithm can be introduced to decompose complex signals into multiple intrinsic mode functions (IMFs), which helps to separate and identify electric field components from different sources. In addition, adaptive filtering algorithms such as least mean square (LMS) or recursive least squares (RLS) filtering can be implemented to dynamically suppress background noise and interference and improve the signal-to-noise ratio of the signal. For long-term monitoring data, trend analysis and anomaly detection algorithms can be developed to identify the patterns of electric field changes and abnormal events, providing a basis for predictive maintenance and fault diagnosis.

[0121] In another optional embodiment, a distributed electric field monitoring network and data fusion system can be developed. Multiple sensor nodes are arranged in different locations to measure the electric field distribution at the same time, and the data is transmitted to a central node or cloud server via a wireless network. The system uses data fusion algorithms, such as Kalman filtering or Bayesian estimation, to integrate data from multiple nodes to generate more accurate electric field distribution maps and dynamic change models. In addition, the system can also integrate machine learning algorithms, such as support vector machines (SVM) or deep neural networks (DNN), to learn electric field change patterns through historical data and achieve intelligent identification and prediction. For example, the model can be trained to identify specific electric field characteristics caused by abnormal electrical equipment, or to predict electric field change trends caused by lightning activity.

[0122] It should be noted that digital signal processing is a key step in transforming raw measurement data into valuable information. The selection and implementation of processing algorithms require consideration of multiple factors, including signal characteristics, application requirements, processing resources, and real-time performance. Different processing strategies may be required for different types of electric field signals: power-frequency electric fields focus on the stability of the fundamental frequency amplitude and phase; harmonic electric fields require precise analysis of spectral components and their variations; and transient electric fields require the capture of rapidly changing characteristics and temporal patterns. In practical applications, processing algorithms must also be robust and adaptable, maintaining reliable performance in diverse environments and conditions. Furthermore, system design must consider energy efficiency. Especially in self-powered scenarios, strategies such as event-triggered processing and dynamic adjustment of processing complexity can be employed to minimize energy consumption while ensuring necessary analysis capabilities. Finally, the presentation and transmission of processing results must be flexibly designed based on user needs and system conditions to ensure effective communication and support decision-making.

[0123] Furthermore, this embodiment also provides a miniaturized wireless self-powered AC electric field measurement system, comprising:

[0124] RF energy harvesting module, used to obtain RF energy in the electric field environment and convert the RF energy into DC power through a microstrip antenna, a voltage doubler rectifier circuit and an energy management circuit;

[0125] An electric field sensing module is used to collect AC electric field signals through a differential dual-electrode sensor structure and generate electric field voltage signals;

[0126] A signal processing module is used to amplify the voltage signal through an instrumentation amplifier and obtain a digital signal of the electric field signal through an analog-to-digital conversion circuit;

[0127] The data analysis module is used to process and analyze AC electric field information based on digital signals.

[0128] In summary, the design of an RF energy harvesting system consisting of a microstrip antenna, a voltage-doubling rectifier circuit, and an energy management circuit addresses the challenges of traditional electric field sensors, which rely on batteries for power and often require frequent battery replacement, are bulky, hinder integration, and generate environmental pollution from battery waste. This system continuously harvests RF energy from the environment and converts it into stable DC power, enabling the sensing system to operate autonomously for long periods of time, significantly improving its practicality and reliability. This eliminates the high maintenance costs of frequent battery replacements, reducing the system's total lifecycle cost, particularly in scenarios involving large-scale sensor deployments within smart grids.

[0129] By adopting a differential dual-electrode sensor structure, the electric field measurement system is significantly simplified compared to traditional single-electrode D-dot sensors. This structure forms an electric field between two electrodes, generating a potential difference proportional to the external electric field strength. This eliminates the need for subsequent integration circuitry, significantly reducing signal processing complexity and the accumulation of integral errors in the circuit. Furthermore, the floating potential difference between the electrode pairs is independent of the ground reference, improving the system's anti-interference capabilities and making measurement results more accurate and reliable. This makes it particularly suitable for electric field measurements in complex electromagnetic environments.

[0130] The weak electric field signal is amplified and digitally converted by a high-precision instrumentation amplifier, which improves the sensitivity and accuracy of the system measurement. This method can adapt to a wide range of electric fields from 0.5kV / m to 10kV / cm, and the linearity is as high as R 2 >0.99995, far exceeding the performance of traditional electric field sensors. The system also exhibits excellent response characteristics to three common electric field signals: sine wave, triangle wave, and square wave. Its operating frequency range is 10Hz to 100kHz, expanding the application scenarios of electric field sensors and enabling them to meet a variety of measurement needs, from industrial frequency electric fields to high-frequency electric fields.

[0131] By configuring instrumentation amplifiers with different bandwidth characteristics (AD8226 and AD8421), accurate measurement of fast, transient, and strong electric field signals is achieved. This method addresses the problem of insufficient response speed of traditional electric field sensors when measuring high-frequency transient signals such as lightning fields. In particular, the AD8421 high-bandwidth amplifier achieves a wave front time of 2.62μs, close to the actual lightning field wave front time (2.08μs). This significantly improves the measurement accuracy of special electric field signals such as lightning fields, providing reliable technical support for lightning protection of power systems.

[0132] By preprocessing the digitized electric field signal to remove DC offset, eliminate trends, and suppress noise, combined with time-domain and frequency-domain analysis techniques, the system can extract key parameters of the electric field signal, such as peak value, RMS value, crest factor, and spectral characteristics. This comprehensive signal processing approach not only improves the reliability of measurement data but also extracts valuable information from complex electric field environments, providing data support for power system status monitoring and fault diagnosis, and promoting the information-based and intelligent development of smart grids.

[0133] Example 2

[0134] Reference Figure 2 - Figure 12 , which is the second embodiment of the present invention, provides a miniaturized wireless self-powered AC electric field measurement method. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0135] The overall device includes a microstrip antenna, a voltage-doubling rectifier circuit, an energy management circuit, and electric field sensor hardware circuitry. A single microstrip antenna consists of a dielectric substrate, a radiator, and a ground plane. A thin metal layer on the bottom of the substrate is connected to the ground plane, while the top surface is photolithographically shaped to create the radiator. RF energy is transmitted to the antenna via a feeder line, generating an electromagnetic signal between the patch and the ground plane. This electromagnetic signal is generated by the excited electromagnetic field and radiated through the gap between the ground plane and the patch.

[0136] A dual-branch stub structure is used for impedance matching to address the nonlinearity of the rectifier circuit at different frequencies, thereby improving energy transmission and conversion efficiency. The energy management module is designed with the BQ25570 chip as the core, using supercapacitors as energy storage elements for energy storage and release. The energy management module utilizes the BQ25570 in its peripheral circuitry to boost and regulate the DC voltage output by the RF-DC rectifier module and efficiently harvest energy. This output provides a stable and controllable DC voltage to the back-end sensor load, ensuring stable and continuous system operation.

[0137] Based on the operating principle of the traditional single-electrode D-dot sensor, an improved differential dual-electrode sensor structure is proposed. This dual-electrode structure generates an electric field between the pair of electrodes, generating a suspended potential difference that serves as the input for the subsequent measurement system. This structure not only reduces the measurement resistance introduced by traditional single-electrode D-dot sensors when measuring electric fields, simplifying the sensor structure, but also ensures that the electric field voltage signals between the two electrodes are proportional, eliminating the need for subsequent integration circuitry, simplifying the measurement system's functionality, and preventing the integration circuit's influence on the sensor's output signal. The designed electric field sensor operates on the principle that a high-voltage AC source applies voltage to the sensor through the air distributed capacitance and the sensor distributed capacitance. To obtain the voltage value of the sensor distributed capacitance, an instrumentation amplifier is used to amplify the voltage signal, and an analog-to-digital conversion circuit is used to obtain the voltage digital signal.

[0138] Test the output characteristics of the RF energy collector in this device. The center frequency of the single microstrip antenna designed in this embodiment is 2.404GHz, and the bandwidth is about 50MHz. A double-branch stub structure is used for impedance matching, and the center frequency of the designed rectifier circuit is 2.419GHz. The reflection coefficient at the center frequency is -28.982dB, where the operating frequency includes the operating frequency of the microstrip antenna. This embodiment uses a RF signal source + RF amplifier system as a RF signal generator. The operating frequency can be from 900MHz to 3GHz, and the transmission power can be from 10mW to 800mW. This RF transmission source is used to test the RF energy collection circuit. The output DC voltage and output power of the RF energy collection circuit are tested under different distance conditions. The test results are as follows. Figure 8The measurement results show that the output characteristics of the RF energy harvester vary significantly within a range of 40 to 60 cm from the transmitter. However, within a range of 60 to 120 cm, the output characteristics vary more gradually, which is related to the energy distribution of the transmitter. Overall, the designed RF energy harvesting circuit maintains an output voltage greater than 2 V and an output power greater than 0.8 mW within the specified distance range.

[0139] Test the frequency response characteristic index of this device. In this embodiment, a sine wave electric field with an amplitude of 0.75kV / cm is selected for the low frequency band (below 10kHz) and a sine wave electric field with an amplitude of 13.75V / cm is selected for the high frequency band (10kHz and above) to test the electric field sensor respectively, change the frequency of the electric field signal, and detect the amplitude of the sensor output. According to the electric field waveform fitting curve tested, the corresponding relationship between the digital signal size output by the electric field sensor and the actual electric field waveform size is obtained, and the corresponding frequency response curve is obtained as shown in the figure. Figure 9 As shown in the figure, the frequency response curve shows that the ordinate represents the ratio of the output electric field signal obtained from the sensor test to the actual electric field signal, while the abscissa represents the frequency of the test electric field signal. When the electric field signal frequency ranges from 10Hz to 100kHz, the ratio of the output signal to the actual signal is close to 0dB, indicating that the two signals are essentially equal. Therefore, it can be concluded that the designed AC electric field sensor can effectively measure electric field frequencies between 10Hz and 100kHz.

[0140] Test the output linearity index of this device. This embodiment uses a 50Hz sinusoidal AC electric field as the test signal, changes its electric field amplitude, measures the output size of the electric field sensor, and tests the linear fit between the electric field amplitude and the sensor output signal. As the test electric field amplitude increases, the sensor output signal amplitude also increases. At this time, the corresponding output response curve is obtained, and the difference between the output signal waveform and the actual electric field waveform is compared. Figure 10 The figure shows the electric field fitting waveform of the typical amplitude. According to the test results, Figure 10 (a) The output linearity test shows a fitting degree of R2 > 0.99998, and the minimum resolution (i.e., the minimum value that the sensor can measure) is 165 V / m / Hz1 / 2; Figure 10 (b) reflects the gap between the output waveform of the electric field sensor and the actual electric field waveform, and its output value has almost no delay and phase shift.

[0141] Testing the output performance indicators of common electric field waveforms of this device. Regarding the sensor's output performance, this embodiment tested two other common electric field waveforms: square wave and triangle wave. By testing the electric field conditions of different waveforms, the applicable scenarios and scope of the electric field sensor were verified. Here, two electric field waveforms with frequencies of 50Hz and 500Hz were used as the test electric field signals. The test results are shown in Figure 11. The test waveforms show that the fit R2 for the triangle wave signal is greater than 0.9999, indicating that the sensor can well measure and restore the triangle wave waveform. The fit R2 for the square wave signal is greater than 0.95. The test waveforms show spikes at the edges of the square wave, which are primarily affected by the rise time. Furthermore, as the electric field frequency increases, the peak fluctuations become more pronounced, a phenomenon known as the Gibbs phenomenon. Although square wave signals can be expanded using a Fourier series, consisting of countless sinusoidal signals, the sensor's frequency response characteristics are no longer constant at high frequencies and differ from those in the mid-frequency range, making it impossible to accurately restore the electric field amplitude. This results in spikes at the edges of the square wave. However, based on the degree of fitting, it can still be considered that the sensor can measure and restore square wave signals well.

[0142] Test the output performance of this device in a lightning environment to verify more application scenarios of the electric field sensor. This embodiment selects the 1.2 / 50μs standard lightning impulse voltage specified in the IEC standard and the national standard of my country as the lightning test voltage, that is, the standard lightning impulse voltage with a wavefront time of 1.2μs (±30%) and a wave tail time of 50μs (±20%), and a peak value of 10kV / m. The test results are as follows Figure 12 As shown in the figure, the sensor test results are generally consistent with the oscilloscope test results. However, the main difference between the two test results is the peak time data. The black square data shows the oscilloscope test results, with a peak time of 2.08μs, which is closest to the actual lightning field waveform. The red circle data shows the test results using the AD8226 instrumentation amplifier, with a peak time of 4.5μs. The blue triangle data shows the test results using the AD8421 instrumentation amplifier, with a peak time of 2.62μs, which is close to the oscilloscope test performance. The main reason for this is the difference in the frequency response characteristics of the instrumentation amplifier. At a gain of 10, the AD8226 has a bandwidth of only 150kHz, resulting in a longer response time to the lightning signal and a peak time longer than the actual lightning duration. At a gain of 10, the AD8421 has a bandwidth of 10MHz, resulting in a shorter response time. To further increase the frequency, an instrumentation amplifier or differential amplifier with a larger bandwidth-gain product can be used.

[0143] According to the above embodiments, the actual output performance of the designed RF energy harvester meets the design requirements and can effectively drive the electric field sensor to perform periodic operation. The designed differential two-electrode AC electric field sensor can be well applied in sine wave, triangle wave, and square wave test scenarios. The test electric field frequency range is 10Hz to 100kHz, the range is 0.5kV / m to 10kV / cm, the minimum resolution is 165V / m / Hz1 / 2, the output linearity is R2>0.99995 at a frequency of 50Hz, and the lightning field output fit is good. It meets the design requirements of miniaturization, high precision, low distortion, and low power consumption of electric field sensors and is suitable for testing applications in complex electric field environments.

[0144] Example 3

[0145] This embodiment also provides a computer device suitable for a miniaturized wireless self-powered AC electric field measurement method, including a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement a forced oscillation detection and positioning method for a distribution network as proposed in the above embodiment.

[0146] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0147] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A miniaturized wireless self-powered AC electric field measurement method, characterized by: The method includes obtaining radio frequency energy in an electric field environment and converting the radio frequency energy into direct current energy through a radio frequency energy collection system composed of a microstrip antenna, a voltage doubling rectifier circuit and an energy management circuit; The AC electric field signal is collected through a differential dual-electrode sensor structure to generate an electric field voltage signal; The voltage signal is amplified by an instrumentation amplifier, and a digital signal of the electric field signal is obtained by an analog-to-digital conversion circuit; Process and analyze AC electric field information based on digital signals.

2. The miniaturized wireless self-powered AC electric field measurement method according to claim 1, wherein: The radio frequency energy harvesting system comprises: A single microstrip antenna is composed of a dielectric substrate, a radiator and a ground plane; The voltage doubler rectifier circuit uses a double-branch stub structure for impedance matching to convert the collected RF energy into DC power; The energy management circuit is designed with the BQ25570 chip as the core and uses supercapacitors as energy storage elements to store and release electrical energy.

3. The miniaturized wireless self-powered AC electric field measurement method according to claim 2, wherein: The monomer microstrip antenna comprises: The thin metal layer at the bottom of the substrate is connected to the ground plane, and the front side is made into a radiator of a specific shape using a photolithography process; The radio frequency energy is transmitted to the antenna through the feeder, generating an electromagnetic signal between the patch and the ground plane, which is radiated through the gap between the ground plane and the patch.

4. The miniaturized wireless self-powered AC electric field measurement method according to claim 3, wherein: The differential dual-electrode sensor structure comprises: A pair of electrodes is set up, an electric field is formed between the electrodes, and a suspended potential difference is generated as the input of the measurement system; The electric field voltage signals between the electrodes are in direct proportion and no subsequent integration circuit is required.

5. The miniaturized wireless self-powered AC electric field measurement method according to claim 4, characterized in that: The AC electric field signal includes a sine wave electric field signal, a triangle wave electric field signal and a square wave electric field signal, and the operating frequency range is 10 Hz to 100 kHz.

6. The miniaturized wireless self-powered AC electric field measurement method according to claim 5, characterized in that: The frequency range of the measured electric field information is 10 Hz to 100 kHz, and the measurement range is 0.5 kV / m to 10 kV / cm.

7. The miniaturized wireless self-powered AC electric field measurement method according to claim 6, characterized in that: Also includes: The lightning field is measured by using different types of instrumentation amplifiers, including the AD8226 instrumentation amplifier and the AD8421 instrumentation amplifier.

8. A miniaturized wireless self-powered AC electric field measurement system, based on the miniaturized wireless self-powered AC electric field measurement method according to any one of claims 1 to 7, characterized in that: It also includes a radio frequency energy harvesting module for acquiring radio frequency energy in an electric field environment and converting the radio frequency energy into direct current energy through a microstrip antenna, a voltage doubling rectifier circuit and an energy management circuit; An electric field sensing module is used to collect AC electric field signals through a differential dual-electrode sensor structure and generate electric field voltage signals; A signal processing module is used to amplify the voltage signal through an instrumentation amplifier and obtain a digital signal of the electric field signal through an analog-to-digital conversion circuit; The data analysis module is used to process and analyze AC electric field information based on digital signals.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the miniaturized wireless self-powered AC electric field measurement method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the miniaturized wireless self-powered AC electric field measurement method according to any one of claims 1 to 7 are implemented.

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