Feedthrough coupling separation method and system for micro electric field sensor

Abstract

The present invention belongs to the technical field of electronic measuring instruments and discloses a feedthrough coupling separation method and system for a micro electric field sensor. The method comprises: applying a first drive voltage between a first drive electrode and a side anchor point, applying a second drive voltage between a third drive electrode and a side anchor point, applying a third drive voltage between a second drive electrode and the other side anchor point, and applying a fourth drive voltage between a fourth drive electrode and the other side anchor point; determining a feedthrough coupling current on a positive sensing electrode, determining a feedthrough coupling current on a negative sensing electrode, determining a total differential feedthrough coupling current, and separating the total differential feedthrough coupling current and a sensing signal. The present invention can separate the frequency spectrum between the drive signal and the sensing signal to solve the problem of feedthrough interference in the sensing response of the micro electric field sensor. No additional structure is required, and the method is simple and easy to implement.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic measuring instruments, and in particular relates to a feedthrough coupling separation method and system for a miniature electric field sensor. Background Art

[0002] Electric field sensors are widely used in power transmission, aerospace, weather forecasting, petrochemicals, and other industries. With the emergence of the Internet of Things (IoT) and micro-nanofabrication technologies, micro electric field sensors have emerged. They offer low power consumption, miniaturization, and high integration, making them suitable for low-cost, high-volume production.

[0003] Based on their sensing principles, micro electric field sensors can be categorized as electrostatic induction, electro-optical effect, inverse piezoelectric effect, electrocaloric effect, and magnetoelectric effect. Electrostatic induction electric field sensors offer advantages in measuring static and low-frequency electric fields. Based on electrostatic induction, they achieve DC electric field modulation and measurement through the periodic shielding motion of a microstructure (shielding electrode) against a detection structure (detection electrode) in the electric field, thus modulating the sensing capacitance.

[0004] Typical drive electrode structures commonly used in micro electric field sensors include electrostatic drive, thermal drive, and piezoelectric drive. Among them, the electrostatic comb drive structure has become one of the most important drive methods in MEMS (Microelectromechanical Systems) due to its advantages such as low power consumption and high speed.

[0005] One of the technical challenges associated with electrostatic actuation and capacitive sensing is dealing with the feedthrough effect of coupled drive and sense signals. Feedthrough can be caused by direct cross-coupling between the drive and sense electrodes and / or electrical non-idealities in the sensing circuitry and packaging.

[0006] One approach to reducing feedthrough is to use differential drive and sensing, but existing technologies rely on optimizing device structure and electrode geometry. Furthermore, due to the back-and-forth oscillation of the electric field sensor's shielding electrode, the coupling capacitance also fluctuates. Whether it's layout design, process implementation, resonance control, or package connection issues, cross-coupling and imbalance can still cause feedthrough current. Summary of the Invention

[0007] To address the above problems, the present invention provides a feedthrough coupling separation method and system for a micro electric field sensor, which adopts the following technical solutions:

[0008] A method for separating feedthrough coupling of a micro electric field sensor comprises the following steps:

[0009] A first driving voltage is applied between the first driving electrode and the anchor point on one side, a second driving voltage is applied between the third driving electrode and the anchor point on one side, a third driving voltage is applied between the second driving electrode and the anchor point on the other side, and a fourth driving voltage is applied between the fourth driving electrode and the anchor point on the other side, wherein the first driving voltage, the second driving voltage, the third driving voltage, and the fourth driving voltage are all superimposed DC bias and AC voltage, and the first driving voltage and the second driving voltage have the same voltage value but opposite directions, and the third driving voltage and the fourth driving voltage have the same voltage value but opposite directions;

[0010] determining a feedthrough coupling current on the positive sensing electrode according to the first driving voltage, the third driving voltage, a first coupling capacitance between the first driving electrode and the positive sensing electrode, and a second coupling capacitance between the second driving electrode and the positive sensing electrode;

[0011] determining a feedthrough coupling current on the negative sensing electrode according to the second driving voltage, the fourth driving voltage, a third coupling capacitance between the third driving electrode and the negative sensing electrode, and a fourth coupling capacitance between the fourth driving electrode and the negative sensing electrode;

[0012] determining a total differential feedthrough coupling current according to the feedthrough coupling current on the positive sensing electrode and the feedthrough coupling current on the negative sensing electrode;

[0013] Based on the linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal, the total differential feedthrough coupling current and the sensing signal are separated.

[0014] Furthermore, the voltage values ​​of the first driving voltage and the second driving voltage are specifically as follows:

[0015]

[0016] Where, are the voltage values ​​of the first driving voltage and the second driving voltage, is the DC bias voltage, is the AC voltage, is the angular frequency of the excitation, For time.

[0017] Furthermore, the voltage values ​​of the third driving voltage and the fourth driving voltage are specifically as follows:

[0018]

[0019] Where, are the voltage values ​​of the third driving voltage and the fourth driving voltage, is the DC bias voltage, is the AC voltage, is the angular frequency of the excitation, For time.

[0020] Furthermore, the first coupling capacitance between the first driving electrode and the positive sensing electrode is as follows:

[0021]

[0022] Where, is the first coupling capacitor, is the initial capacitance of the first driving electrode and the positive sensing electrode at the equilibrium position, is the variation coefficient of the first coupling capacitance.

[0023] Furthermore, the second coupling capacitance between the second driving electrode and the positive sensing electrode is as follows:

[0024]

[0025] Where, is the second coupling capacitor, is the initial capacitance of the second driving electrode and the positive sensing electrode at the equilibrium position, is the variation coefficient of the second coupling capacitance.

[0026] Furthermore, the feedthrough coupling current on the positive sensing electrode is determined according to the first driving voltage, the third driving voltage, the first coupling capacitance between the first driving electrode and the positive sensing electrode, and the second coupling capacitance between the second driving electrode and the positive sensing electrode, as follows:

[0027]

[0028] Where, represents the feedthrough coupled current on the positive sensing electrode.

[0029] Furthermore, the third coupling capacitance between the third driving electrode and the negative sensing electrode is as follows:

[0030]

[0031] Where, is the third coupling capacitor.

[0032] Furthermore, the fourth coupling capacitor between the fourth driving electrode and the negative sensing electrode is specifically as follows:

[0033]

[0034] Where, is the fourth coupling capacitor.

[0035] Furthermore, the feedthrough coupling current on the negative sensing electrode is determined according to the second driving voltage, the fourth driving voltage, the third coupling capacitance between the third driving electrode and the negative sensing electrode, and the fourth coupling capacitance between the fourth driving electrode and the negative sensing electrode, as follows:

[0036]

[0037] Where, represents the feedthrough coupled current on the negative sensing electrode.

[0038] Furthermore, the total differential feedthrough coupling current is determined based on the feedthrough coupling current on the positive sensing electrode and the feedthrough coupling current on the negative sensing electrode, as follows:

[0039]

[0040] Where, represents the total differential feedthrough coupled current.

[0041] Furthermore, based on the linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal, the total differential feedthrough coupling current and the sensing signal are separated as follows:

[0042] The multiple relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal is determined, and the total differential feedthrough coupling current is eliminated by filtering to achieve spectrum separation of the total differential feedthrough coupling current and the sensing signal.

[0043] The present invention also provides a feedthrough coupling separation system for a micro electric field sensor, comprising:

[0044] a power supply module, configured to apply a first drive voltage between the first drive electrode and the anchor point on one side, apply a second drive voltage between the third drive electrode and the anchor point on one side, apply a third drive voltage between the second drive electrode and the anchor point on the other side, and apply a fourth drive voltage between the fourth drive electrode and the anchor point on the other side, wherein the first drive voltage, the second drive voltage, the third drive voltage, and the fourth drive voltage are all superimposed DC bias and AC voltage, and the first drive voltage and the second drive voltage have the same voltage value but opposite directions, and the third drive voltage and the fourth drive voltage have the same voltage value but opposite directions;

[0045] a first calculation module, configured to determine a feedthrough coupling current on the positive sensing electrode based on the first driving voltage, the third driving voltage, a first coupling capacitance between the first driving electrode and the positive sensing electrode, and a second coupling capacitance between the second driving electrode and the positive sensing electrode;

[0046] a second calculation module, configured to determine a feedthrough coupling current on the negative sensing electrode based on the second driving voltage, the fourth driving voltage, a third coupling capacitance between the third driving electrode and the negative sensing electrode, and a fourth coupling capacitance between the fourth driving electrode and the negative sensing electrode;

[0047] a third calculation module, configured to determine a total differential feedthrough coupling current based on the feedthrough coupling current on the positive sensing electrode and the feedthrough coupling current on the negative sensing electrode;

[0048] The filtering module is used to separate the total differential feedthrough coupling current and the sensing signal based on the linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal.

[0049] Beneficial effects of the present invention:

[0050] The present invention can be used for differential electrostatic comb excitation and differential detection type micro electric field sensors, and can separate the frequency spectrum between the driving signal and the sensing signal to solve the problem that the sensing response of the micro electric field sensor is interfered by feedthrough. No additional structure is required, and the method is simple and easy to implement.

[0051] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0053] Figure 1 FIG2 shows a schematic diagram of the architecture of a differential electrostatic comb-tooth excitation differential detection micro electric field sensor according to an embodiment of the present invention;

[0054] Figure 2 A schematic diagram showing a driving voltage applied to both sides of a differential electrostatic comb excitation differential detection micro electric field sensor according to an embodiment of the present invention is shown;

[0055] Figure 3 A schematic flow chart of a feedthrough coupling separation method for a micro electric field sensor according to an embodiment of the present invention is shown;

[0056] Figure 4A structural schematic diagram of a feedthrough coupling separation system of a micro electric field sensor according to an embodiment of the present invention is shown.

[0057] In the figure: 1. First folding beam; 2. Second folding beam; 3. First driving electrode; 4. Second driving electrode; 5. Third driving electrode; 6. Fourth driving electrode; 7. Movable mass block; 8. Positive sensing electrode; 9. Negative sensing electrode; 10. Movable comb teeth; 11. Fixed comb teeth; 12. Shielding electrode; 13. Crossbeam; 14. Anchor point. DETAILED DESCRIPTION

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0059] It should be noted that the terms "first," "second," etc., in this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so as to facilitate the embodiments of the present application described herein.

[0060] The present invention provides a feedthrough coupling separation method and system for a micro electric field sensor, which can be used for differential electrostatic comb excitation and differential detection micro electric field sensors. The method uses frequency conversion technology to cause spectrum separation between the drive signal and the sensing signal to solve the problem that the sensing response of the micro electric field sensor is interfered by feedthrough.

[0061] like Figure 1 As shown, the architecture of the differential electrostatic comb-tooth excitation differential detection type micro electric field sensor is first introduced. The differential electrostatic comb-tooth excitation differential detection type micro electric field sensor includes a first folding beam 1, a second folding beam 2, a first driving electrode 3, a second driving electrode 4, a third driving electrode 5, a fourth driving electrode 6, a movable mass block 7, a positive sensing electrode 8 and a negative sensing electrode 9.

[0062] Among them, the first drive electrode 3, the second drive electrode 4, the third drive electrode 5, and the fourth drive electrode 6 all include movable comb teeth 10 and fixed comb teeth 11 that are staggered, and the movable comb teeth 10 and the fixed comb teeth 11 constitute multiple parallel plate capacitor structures; the movable mass block 7 includes a shielding electrode 12 and a beam 13.

[0063] The ends of the crossbeam 13 are connected to one end of the first folded beam 1 and one end of the second folded beam 2, respectively. The other ends of the first folded beam 1 and the other ends of the second folded beam 2 are fixed to the substrate via anchor points 14. The first drive electrode 3 and the third drive electrode 5 are arranged near the first folded beam 1 and are mirror-imaged on either side of the crossbeam 13. The second drive electrode 4 and the fourth drive electrode 6 are arranged near the second folded beam 2 and are mirror-imaged on either side of the crossbeam 13. The positive sensing electrode 8 is arranged between the first drive electrode 3 and the second drive electrode 4, and the negative sensing electrode 9 is arranged between the third drive electrode 5 and the fourth drive electrode 6. A shielding electrode 12 is arranged on one side of each negative sensing electrode 9 and each positive sensing electrode 8, and one end of each shielding electrode 12 is connected to the crossbeam 13.

[0064] One end of the fixed comb teeth 11 of the first drive electrode 3, one end of the fixed comb teeth 11 of the second drive electrode 4, one end of the fixed comb teeth 11 of the third drive electrode 5, and one end of the fixed comb teeth 11 of the fourth drive electrode 6 are all connected to the fixed electrode as the input end of the voltage signal; one end of the movable comb teeth 10 of the first drive electrode 3, one end of the movable comb teeth 10 of the second drive electrode 4, one end of the movable comb teeth 10 of the third drive electrode 5, and one end of the movable comb teeth 10 of the fourth drive electrode 6 are all connected to the beam 13.

[0065] The first folding beam 1 and the second folding beam 2 provide elastic restoring force for the system movement. In the prior art, in order to reduce common-mode interference, the resonator generally adopts a bilateral electrostatic excitation method when working. The first folding beam 1, the second folding beam 2, the movable comb teeth 10 of the first drive electrode 3, the movable comb teeth 10 of the second drive electrode 4, the movable comb teeth 10 of the third drive electrode 5, the movable comb teeth 10 of the fourth drive electrode 6 and the movable mass block 7 are all grounded; a DC bias and a reverse AC drive voltage are applied to the drive electrodes on both sides of the beam 13, that is, a first drive voltage is applied between the first drive electrode 3 and the third drive electrode 5, and a second drive voltage is applied between the second drive electrode 4 and the fourth drive electrode 6, wherein the first drive voltage and the second drive voltage are both superimposed DC bias and AC voltage, and the AC voltage directions in the first drive voltage and the second drive voltage are opposite, as follows:

[0066] (1)

[0067] (2)

[0068] Where, is the first driving voltage, is the second driving voltage, is the DC bias voltage, is the AC voltage, is the angular frequency of the excitation, For time.

[0069] A periodic electrostatic excitation force is generated between the movable comb teeth 10 and the fixed comb teeth 11. When the electrostatic attraction force on one side increases over time, the electrostatic attraction force on the other side decreases accordingly, and the two increase while the other decreases. The movable comb teeth 10 generate horizontal vibrations under the electrostatic force and the elastic restoring force of the first folding beam 1 and the second folding beam 2. The electromechanical coupling between the movable comb teeth 10 and the fixed comb teeth 11 serves as the electromechanical energy conversion module of the entire resonator structure. The input voltage signal is converted into a mechanical vibration signal, and the resonant frequency modulates the special measurement signal. The electrical signal obtained by the positive and negative sensitive structures is differentially output to the detection end for detection, thereby achieving its sensing purpose. The above existing method will cause feed-through current due to the unbalanced coupling of the left and right driving voltages, and the frequency band of the feed-through current is the same as the induced current, and the two cannot be distinguished.

[0070] like Figure 2 and Figure 3 As shown, the feedthrough coupling separation method of the micro electric field sensor of the present invention can be used for the above-mentioned differential electrostatic comb excitation differential detection micro electric field sensor. It uses the principle that the electrostatic force is proportional to the square of the driving voltage. The driving electrodes on both sides apply opposite driving voltages, but the magnitude and direction of the electrostatic force remain unchanged. The method includes the following steps:

[0071] S1, applying a first driving voltage between the first driving electrode 3 and the anchor point 14 on one side, applying a second driving voltage between the third driving electrode 5 and the anchor point 14 on one side, applying a third driving voltage between the second driving electrode 4 and the anchor point 14 on the other side, and applying a fourth driving voltage between the fourth driving electrode 6 and the anchor point 14 on the other side. Figure 2 As shown, the first driving voltage, the second driving voltage, the third driving voltage and the fourth driving voltage are all superimposed DC bias and AC voltage, and the first driving voltage and the second driving voltage have the same voltage value but opposite directions, and the third driving voltage and the fourth driving voltage have the same voltage value but opposite directions.

[0072] The voltage values ​​of the first driving voltage and the second driving voltage are as shown in formula (1), and the voltage values ​​of the third driving voltage and the fourth driving voltage are as shown in formula (2).

[0073] S2. Determine a first coupling capacitance between the first driving electrode 3 and the positive sensing electrode 8 , and a second coupling capacitance between the second driving electrode 4 and the positive sensing electrode 8 .

[0074] When the shielding electrode 12 modulates the electric field of the sensing electrode back and forth, it essentially modulates the capacitance between the sensing electrode and the surrounding conductor. Therefore, the capacitance between the fixed driving electrode and the fixed sensing electrode is a function of the resonant displacement. Therefore, the first coupling capacitance and the second coupling capacitance can be determined as:

[0075] (3)

[0076] (4)

[0077] Where, is the first coupling capacitor, is the second coupling capacitor, is the initial capacitance of the first driving electrode 3 and the positive sensing electrode 8 at the equilibrium position, is the initial capacitance of the second driving electrode 4 and the positive sensing electrode 8 at the equilibrium position, 、 are the variation coefficients of the first coupling capacitance and the second coupling capacitance respectively.

[0078] S3. Determine the feedthrough coupling current on the positive sensing electrode 8 according to the first driving voltage, the third driving voltage, the first coupling capacitor, and the second coupling capacitor, as follows:

[0079] according to Substituting into formula 1-4, the feedthrough coupling current on the positive sensing electrode 8 can be obtained as follows:

[0080] (5)

[0081] Where, is the current, is the capacitance, Indicates voltage, Indicates time, represents the feedthrough coupling current on the positive sensing electrode 8.

[0082] S4 . Determine a third coupling capacitance between the third driving electrode 5 and the negative sensing electrode 9 , and a fourth coupling capacitance between the fourth driving electrode 6 and the negative sensing electrode 9 .

[0083] Since the sensor layout and its motion state are centrally symmetrical, the third coupling capacitor and the fourth coupling capacitor can be obtained as follows:

[0084] (6)

[0085] (7)

[0086] Where, is the third coupling capacitor, is the fourth coupling capacitor.

[0087] Wherein, is the third coupling capacitor, is the fourth coupling capacitor.

[0088] S5. Determine the feedthrough coupling current on the negative sensing electrode 9 according to the second driving voltage, the fourth driving voltage, the third coupling capacitor, the fourth coupling capacitor, the third coupling capacitor, and the fourth coupling capacitor, as follows:

[0089] (8)

[0090] Where, represents the feedthrough coupling current on the negative sensing electrode 9.

[0091] S6. Determine the total differential feedthrough coupling current according to the feedthrough coupling current on the positive sensing electrode 8 and the feedthrough coupling current on the negative sensing electrode 9. , as follows:

[0092] (9)

[0093] S7. Separating the total differential feedthrough coupling current and the sensing signal based on a linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal, including:

[0094] The multiple relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal is determined, and the total differential feedthrough coupling current is eliminated by filtering to achieve spectrum separation of the total differential feedthrough coupling current and the sensing signal.

[0095] Equation (9) shows that the frequency of the total differential feedthrough coupled current is a multiple of the resonant frequency, that is, twice the sensing signal, and can be eliminated by filtering. The above frequency conversion technology can cause spectral separation between the drive signal and the sensing signal, thereby solving the problem of feedthrough interference in the sensing response of the micro electric field sensor.

[0096] Based on the above-mentioned feedthrough coupling separation method of the micro electric field sensor, Figure 4 As shown, the present invention also provides a feedthrough coupling separation system for a micro electric field sensor, comprising a power supply module, a first calculation module, a second calculation module, a third calculation module and a filter module.

[0097] A power supply module is used to apply a first driving voltage between the first driving electrode 3 and the left anchor point 14, apply a second driving voltage between the third driving electrode 5 and the left anchor point 14, apply a third driving voltage between the second driving electrode 4 and the right anchor point 14, and apply a fourth driving voltage between the fourth driving electrode 6 and the right anchor point 14.

[0098] The first calculation module is used to determine the feedthrough coupling current on the positive sensing electrode 8 based on the first driving voltage, the third driving voltage, the first coupling capacitance between the first driving electrode 3 and the positive sensing electrode 8, and the second coupling capacitance between the second driving electrode 4 and the positive sensing electrode 8.

[0099] The second calculation module is used to determine the feedthrough coupling current on the negative sensing electrode 9 according to the second driving voltage, the fourth driving voltage, the third coupling capacitance between the third driving electrode 5 and the negative sensing electrode 9, and the fourth coupling capacitance between the fourth driving electrode 6 and the negative sensing electrode 9.

[0100] The third calculation module is configured to determine a total differential feedthrough coupling current according to the feedthrough coupling current on the positive sensing electrode 8 and the feedthrough coupling current on the negative sensing electrode 9 .

[0101] The filtering module is used to separate the total differential feedthrough coupling current and the sensing signal based on the linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal.

[0102] The present invention realizes the spectrum separation of the driving feedthrough coupling current frequency and the sensing signal frequency without adding additional structures, and the method is simple and easy to implement.

[0103] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A feedthrough coupling separation method for a micro electric field sensor, characterized in that: The following steps are involved: A first driving voltage is applied between the first driving electrode and the anchor point on one side, a second driving voltage is applied between the third driving electrode and the anchor point on one side, a third driving voltage is applied between the second driving electrode and the anchor point on the other side, and a fourth driving voltage is applied between the fourth driving electrode and the anchor point on the other side, wherein the first driving voltage, the second driving voltage, the third driving voltage, and the fourth driving voltage are all superimposed DC bias and AC voltage, and the first driving voltage and the second driving voltage have the same voltage value but opposite directions, and the third driving voltage and the fourth driving voltage have the same voltage value but opposite directions; determining a feedthrough coupling current on the positive sensing electrode according to the first driving voltage, the third driving voltage, a first coupling capacitance between the first driving electrode and the positive sensing electrode, and a second coupling capacitance between the second driving electrode and the positive sensing electrode; determining a feedthrough coupling current on the negative sensing electrode according to the second driving voltage, the fourth driving voltage, a third coupling capacitance between the third driving electrode and the negative sensing electrode, and a fourth coupling capacitance between the fourth driving electrode and the negative sensing electrode; determining a total differential feedthrough coupling current according to the feedthrough coupling current on the positive sensing electrode and the feedthrough coupling current on the negative sensing electrode; Based on the linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal, the total differential feedthrough coupling current and the sensing signal are separated.

2. The feedthrough coupling separation method of the micro electric field sensor according to claim 1, characterized in that: The voltage values ​​of the first driving voltage and the second driving voltage are as follows: Where, are the voltage values ​​of the first driving voltage and the second driving voltage, is the DC bias voltage, is the AC voltage, is the angular frequency of the excitation, For time.

3. The feedthrough coupling separation method of the micro electric field sensor according to claim 2, characterized in that: The voltage values ​​of the third driving voltage and the fourth driving voltage are specifically as follows: Where, are the voltage values ​​of the third driving voltage and the fourth driving voltage, is the DC bias voltage, is the AC voltage, is the angular frequency of the excitation, For time.

4. The feedthrough coupling separation method of the micro electric field sensor according to claim 3, characterized in that: The first coupling capacitance between the first driving electrode and the positive sensing electrode is as follows: Where, is the first coupling capacitor, is the initial capacitance of the first driving electrode and the positive sensing electrode at the equilibrium position, is the variation coefficient of the first coupling capacitance.

5. The feedthrough coupling separation method of the micro electric field sensor according to claim 4, characterized in that: The second coupling capacitance between the second driving electrode and the positive sensing electrode is as follows: Where, is the second coupling capacitor, is the initial capacitance of the second driving electrode and the positive sensing electrode at the equilibrium position, is the variation coefficient of the second coupling capacitance.

6. The feedthrough coupling separation method of the micro electric field sensor according to claim 5, characterized in that: The feedthrough coupling current on the positive sensing electrode is determined according to the first driving voltage, the third driving voltage, the first coupling capacitance between the first driving electrode and the positive sensing electrode, and the second coupling capacitance between the second driving electrode and the positive sensing electrode, specifically as follows: Where, represents the feedthrough coupled current on the positive sensing electrode.

7. The feedthrough coupling separation method of the micro electric field sensor according to claim 6, characterized in that: The third coupling capacitance between the third driving electrode and the negative sensing electrode is as follows: Where, is the third coupling capacitor.

8. The feedthrough coupling separation method of the micro electric field sensor according to claim 7, characterized in that: The fourth coupling capacitor between the fourth driving electrode and the negative sensing electrode is as follows: Where, is the fourth coupling capacitor.

9. The feedthrough coupling separation method of the micro electric field sensor according to claim 8, characterized in that: The feedthrough coupling current on the negative sensing electrode is determined according to the second driving voltage, the fourth driving voltage, the third coupling capacitance between the third driving electrode and the negative sensing electrode, and the fourth coupling capacitance between the fourth driving electrode and the negative sensing electrode, specifically as follows: Where, represents the feedthrough coupled current on the negative sensing electrode.

10. The feedthrough coupling separation method of a micro electric field sensor according to claim 8, characterized in that: The total differential feedthrough coupling current is determined based on the feedthrough coupling current on the positive sensing electrode and the feedthrough coupling current on the negative sensing electrode, as follows: Where, represents the total differential feedthrough coupled current.

11. The feedthrough coupling separation method of a micro electric field sensor according to any one of claims 1 to 9, characterized in that: Based on the linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal, the total differential feedthrough coupling current and the sensing signal are separated as follows: The multiple relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal is determined, and the total differential feedthrough coupling current is eliminated by filtering to achieve spectrum separation of the total differential feedthrough coupling current and the sensing signal.

12. A feedthrough coupling separation system for a micro electric field sensor, characterized in that: include: a power supply module, configured to apply a first drive voltage between the first drive electrode and the anchor point on one side, apply a second drive voltage between the third drive electrode and the anchor point on one side, apply a third drive voltage between the second drive electrode and the anchor point on the other side, and apply a fourth drive voltage between the fourth drive electrode and the anchor point on the other side, wherein the first drive voltage, the second drive voltage, the third drive voltage, and the fourth drive voltage are all superimposed DC bias and AC voltage, and the first drive voltage and the second drive voltage have the same voltage value but opposite directions, and the third drive voltage and the fourth drive voltage have the same voltage value but opposite directions; a first calculation module, configured to determine a feedthrough coupling current on the positive sensing electrode based on the first driving voltage, the third driving voltage, a first coupling capacitance between the first driving electrode and the positive sensing electrode, and a second coupling capacitance between the second driving electrode and the positive sensing electrode; a second calculation module, configured to determine a feedthrough coupling current on the negative sensing electrode based on the second driving voltage, the fourth driving voltage, a third coupling capacitance between the third driving electrode and the negative sensing electrode, and a fourth coupling capacitance between the fourth driving electrode and the negative sensing electrode; a third calculation module, configured to determine a total differential feedthrough coupling current based on the feedthrough coupling current on the positive sensing electrode and the feedthrough coupling current on the negative sensing electrode; The filtering module is used to separate the total differential feedthrough coupling current and the sensing signal based on the linear relationship between the frequency of the total differential feedthrough coupling current and the frequency of the sensing signal.

Images