An ultra-high sensitivity MEMS micro-pressure sensor
By adjusting the stiffness with tuning electrodes on the resonant beam and adopting a segmented output method, the problem of insufficient sensitivity of resonant pressure sensors in micro-pressure measurement is solved, achieving ultra-high sensitivity and accurate measurement, which is suitable for aerospace, medical and other fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEFEI UNIV OF TECH
- Filing Date
- 2023-08-28
- Publication Date
- 2026-05-29
AI Technical Summary
Existing resonant pressure sensors lack sensitivity and accuracy when measuring micro-pressures. Furthermore, the initial balance problem caused by inconsistent resonator stiffness affects sensor performance, and the output curve exhibits significant nonlinearity under minute pressure disturbances, thus limiting the detection range.
A high-sensitivity MEMS micro-pressure sensor is designed. By setting tuning electrodes on the resonant beam to adjust its stiffness, the natural frequencies of the two resonant beams are made equal. A segmented output method is adopted, combined with symmetrically distributed S-shaped weakly coupled beams, and the pressure value is obtained by measuring the amplitude ratio difference of the resonant beams.
It achieves ultra-high sensitivity and accurate measurement of MEMS micro-pressure sensors, with a wide detection range and a sensitivity improvement of five orders of magnitude, making it suitable for high-sensitivity micro-pressure measurement in aerospace, medical and other fields.
Smart Images
Figure CN117129110B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of MEMS pressure sensor technology, specifically to an ultra-high sensitivity MEMS micro-pressure sensor. Background Technology
[0002] Pressure sensors are commonly used in aerospace and medical fields. Based on different sensing mechanisms, pressure sensors are generally classified into strain gauge, piezoresistive, capacitive, piezoelectric, and resonant types. Among them, resonant sensors are widely used due to their advantages such as small size and light weight.
[0003] The principle of a resonant pressure sensor is to utilize the change in the characteristic frequency of a resonator caused by changes in external pressure, and to indirectly measure the pressure by measuring the change in the characteristic frequency. However, due to existing micromachining conditions and structural designs, resonant pressure sensors are generally used for pressure measurement over a large range. When measuring absolute micro-pressure, their sensitivity is limited, making them unsuitable for applications requiring extremely high sensitivity in micro-pressure measurement.
[0004] To address the low sensitivity of existing frequency-output resonant pressure sensors for measuring micro-pressure, some researchers have proposed a novel resonant pressure sensor composed of two mechanically coupled resonators. This sensor measures pressure by measuring the amplitude ratio of the resonators' vibrations, resulting in a significant improvement in sensitivity compared to traditional frequency-based output pressure sensors. However, residual stress in the resonators caused by micromachining and etching dimensional errors lead to inconsistent stiffness between the two resonators in the weakly coupled resonant system, affecting the initial equilibrium of the system and limiting sensor performance to some extent. Furthermore, related literature uses amplitude ratio as the pressure sensor output. When the sensor experiences small pressure disturbances (input), its output exhibits a mode-shifting region with significant nonlinearity. Therefore, using amplitude ratio output is only suitable for measuring relatively large pressures, limiting the sensor's detection range. Directly applying it to micro-pressure measurements results in poor sensitivity and accuracy. Summary of the Invention
[0005] The purpose of this invention is to provide an ultra-high sensitivity MEMS micro-pressure sensor to overcome the above-mentioned shortcomings.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] An ultra-high sensitivity MEMS micro-pressure sensor includes: a base, a first resonant beam, a second resonant beam, a first weakly coupled beam, a second weakly coupled beam, and four identical first pressure membranes, second pressure membranes, third pressure membranes, and fourth pressure membranes disposed on the base; the first resonant beam is fixed to the first and second pressure membranes respectively via first and second anchor points at both ends; the second resonant beam is fixed to the third and fourth pressure membranes respectively via third and fourth anchor points at both ends; a first tuning electrode and a second tuning electrode are respectively disposed on the outer surfaces of the first and second resonant beams; the first and second weakly coupled beams are S-shaped structures and are symmetrically disposed between the first and second resonant beams;
[0008] The method for achieving ultra-high sensitivity in the MEMS micro-pressure sensor includes the following steps:
[0009] Step 1: Measure the frequency response of different resonant beams in the MEMS micro-pressure sensor under different pressure disturbances, obtain the amplitude of each resonant beam in different vibration modes, and express it as x. i，j This represents the amplitude of the resonant beam j in the i-th mode;
[0010] Step 2: For the amplitudes of each resonant beam measured in Step 1 under different modes, calculate the amplitude ratio between different resonant beams under the i-th mode by division. The calculation formula is η. i，j1，j2 =x i，j1 / x i，j2 (j1≠j2); When calculating the amplitude ratio, the sign is determined by the vibration mode of the system; specifically, if i equals 1, the amplitude ratio calculation result of the first vibration mode is positive, i.e., η 1，j1，j2 The result is taken as positive; if i equals 2, the calculated amplitude ratio of the second-order vibration mode is negative, i.e., η 2，j1，j2 The result is negative.
[0011] Step 3: Calculate the difference between the amplitude ratios of different modes obtained in Step 2 to get the amplitude ratio difference D of the MEMS micro-pressure sensor: When the pressure on the pressure membrane is negative, D = η 1，1，2 -η 2，2，1 When the pressure on the pressure diaphragm is a positive pressure, D + =η 2，1，2 -η 1，2，1 When the pressure diaphragm is not under pressure, |η 1，2，1 -η 2，1，2 |;
[0012] Step 4: The D obtained in Step 3 is the difference in the segmented amplitude ratio under different pressure disturbances, thus obtaining the output curve of the MEMS micro-pressure sensor based on the difference in amplitude ratio and the change in pressure disturbance. This method can realize ultra-high sensitivity detection of MEMS micro-pressure sensor.
[0013] Preferably, the first anchor point, the second anchor point, the third anchor point, and the fourth anchor point are fixed at the center of the outer side of the upper end face of the first pressure membrane, the second pressure membrane, the third pressure membrane, and the fourth pressure membrane, respectively, specifically at a position one-quarter of the length and one-half the width of the outer side of the upper end face.
[0014] Preferably, the length and width of the first tuning electrode and the second tuning electrode are equal.
[0015] Preferably, the length of the first tuning electrode is less than the length of the first resonant beam; the width and height of the first tuning electrode are equal to the width and height of the first resonant beam, respectively; the length of the second tuning electrode is less than the length of the second resonant beam; and the width and height of the second tuning electrode are equal to the width and height of the second resonant beam, respectively.
[0016] The beneficial effects of this invention are as follows:
[0017] This invention discloses an ultra-high sensitivity MEMS micro-pressure sensor. By adjusting the stiffness of the resonant beams with tuning electrodes, the natural frequencies of the two resonant beams are made equal. A higher quality factor is achieved through two symmetrically distributed "S"-shaped weakly coupled beams. Different (segmented) output methods are used to acquire the measured pressure value depending on the pressure applied to the pressure membrane (positive pressure, negative pressure, no pressure). The ultra-high sensitivity implementation method of this MEMS micro-pressure sensor has a wide detection range, exhibiting ultra-high sensitivity and accurate measurement precision when measuring micro-pressures. It is also convenient to use and has good stability. Attached Figure Description
[0018] Figure 1 : A schematic diagram of the structure of the MEMS micro-pressure sensor of the present invention;
[0019] Figure 2 Top view of the MEMS micro-pressure sensor of the present invention;
[0020] Figure 3 : Schematic diagram of the principle of adjusting the natural frequency of the resonant beam by the tuning electrode in the MEMS micro-pressure sensor of the present invention;
[0021] Figure 4 The natural frequency curve of the resonant beam in the MEMS micro-pressure sensor of this invention is adjusted by the spring softening effect.
[0022] Figure 5: A schematic diagram of the vibration of the two resonant beams before and after the manufacturing error is compensated by the tuning electrode in the MEMS micro-pressure sensor of the present invention;
[0023] Figure 6 : A flowchart of the method for achieving ultra-high sensitivity of the MEMS micro-pressure sensor of the present invention.
[0024] Figure 7 The output curve based on characteristic frequency in the MEMS micro-pressure sensor of this invention;
[0025] Figure 8 The graph shows the segmented amplitude ratio difference curve for achieving ultra-high sensitivity detection of MEMS micro-pressure sensor in this invention. Detailed Implementation
[0026] The present invention will be further described below with reference to the embodiments. It should be noted that these are merely examples and descriptions of the inventive concept. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined in the claims, they should all be considered to fall within the protection scope of the present invention.
[0027] Example:
[0028] Figure 1 This is a schematic diagram of the structure of the MEMS micro-pressure sensor according to an embodiment of the present invention. Figure 2 This is a top view of the MEMS micro-pressure sensor according to an embodiment of the present invention. Figure 1 , 2 As shown, an ultra-high sensitivity MEMS micro-pressure sensor of the present invention includes: a base 1-1, a first resonant beam 4-1, a second resonant beam 4-2, a first weak coupling beam 5-1, a second weak coupling beam 5-2, and four identical first pressure membranes 3-1 (under pressure), second pressure membranes 3-2 (under pressure), third pressure membranes 3-3 (not under pressure), and fourth pressure membranes 3-4 (not under pressure) disposed on the base 1-1.
[0029] The first resonant beam 4-1 is fixed at both ends to the first pressure membrane 3-1 and the second pressure membrane 3-2 via the first anchor point 2-1 and the second anchor point 2-2, respectively. The second resonant beam 4-2 is fixed at both ends to the third pressure membrane 3-3 and the fourth pressure membrane 3-4 via the third anchor point 2-3 and the fourth anchor point 2-4, respectively. The first anchor point 2-1, the second anchor point 2-2, the third anchor point 2-3, and the fourth anchor point 2-4 are fixed at the center of the outer side of the upper end face of the first pressure membrane 3-1, the second pressure membrane 3-2, the third pressure membrane 3-3, and the fourth pressure membrane 3-4, specifically at a position one-quarter of the length and one-half the width of the outer side of the upper end face.
[0030] The outer surfaces of the first resonant beam 4-1 and the second resonant beam 4-2 are respectively provided with a first tuning electrode 6-1 and a second tuning electrode 6-2. The stiffness of the first resonant beam 4-1 and the second resonant beam 4-2 is adjusted by the first tuning electrode 6-1 and the second tuning electrode 6-2, respectively, so that they have the same natural frequency after adjustment. Through the action of the first tuning electrode 6-1 and the second tuning electrode 6-2, the natural frequencies of the first resonant beam 4-1 and the second resonant beam 4-2 can be precisely adjusted, thereby compensating for manufacturing errors and ensuring that the first resonant beam 4-1 and the second resonant beam 4-2 have the same frequency characteristics.
[0031] The length and width of the first tuning electrode 6-1 and the second tuning electrode 6-2 are equal. The length of the first tuning electrode 6-1 is less than the length of the first resonant beam 4-1; the width and height of the first tuning electrode 6-1 are equal to the width and height of the first resonant beam 4-1, respectively. The length of the second tuning electrode 6-2 is less than the length of the second resonant beam 4-2; the width and height of the second tuning electrode 6-2 are equal to the width and height of the second resonant beam 4-2, respectively.
[0032] Figure 3 This is a schematic diagram illustrating the principle of adjusting the natural frequency of the resonant beam using a tuning electrode in a MEMS micro-pressure sensor according to an embodiment of the present invention. Figure 3 As shown, the first resonant beam 4-1 and the second resonant beam 4-2 are grounded, and the first tuning electrode 6-1 and the second tuning electrode 6-2 are connected to a DC voltage source. The natural frequencies of the first resonant beam 4-1 and the second resonant beam 4-2 are adjusted by changing the voltage of the DC voltage source.
[0033] Figure 4 This is a graph showing the natural frequency curve of the resonant beam adjusted using the spring softening effect in a MEMS micro-pressure sensor according to an embodiment of the present invention. Figure 4 As shown, the natural frequency of the resonant beam decreases with increasing voltage, exhibiting a negative correlation. This phenomenon is known as the spring softening effect.
[0034] Figure 5 This is a schematic diagram of the vibration of the two resonant beams in the ultra-high sensitivity MEMS micro-pressure sensor of this invention before and after the tuning electrode compensates for manufacturing errors. Figure 5 As shown, residual stress and machining errors inside the resonator caused by micromachining result in different natural frequencies of the first resonant beam 4-1 and the second resonant beam 4-2, which in turn lead to different initial amplitudes. The natural frequency of the first resonant beam 4-1 is lower than that of the second resonant beam 4-2. According to... Figure 3The description states that by increasing the DC voltage applied to the second tuning electrode 6-2 and utilizing the spring softening effect, the natural frequency of the second resonant beam 4-2 is reduced, so that the first resonant beam 4-1 and the second resonant beam 4-2 have the same natural frequency. This solves the problem of different initial amplitudes caused by processing errors, and obtains a MEMS micro-pressure sensor with ultra-high sensitivity.
[0035] The first weakly coupled beam 5-1 and the second weakly coupled beam 5-2 are S-shaped structures, symmetrically arranged between the first resonant beam 4-1 and the second resonant beam 4-2, forming a weakly coupled system. The S-shaped design of the first and second weakly coupled beams allows for a higher quality factor by extending their length and reducing their stiffness. The symmetrical distribution of the first and second weakly coupled beams 5-1 and 5-2 makes the sensor more stable during operation, reducing the influence of external factors and thus improving the stability and reliability of sensor measurements.
[0036] MEMS micro-pressure sensor measurement principle: When all four pressure diaphragms are not under pressure, and the two resonant beams (first resonant beam 4-1 and second resonant beam 4-2) vibrate freely, the amplitudes of the first resonant beam 4-1 and the second resonant beam 4-2 are equal, and their amplitude ratio is 1. When the first pressure diaphragm 3-1 and the second pressure diaphragm 3-2 are subjected to pressure disturbance, the initial equilibrium is disrupted, causing the amplitude ratio of the first resonant beam 4-1 and the second resonant beam 4-2 to no longer be 1. The pressure value to be measured can be obtained by measuring the quantity related to the amplitude ratio of the first resonant beam 4-1 and the second resonant beam 4-2 under different pressure disturbances.
[0037] Figure 6 A flowchart illustrating the method for achieving ultra-high sensitivity in the MEMS micro-pressure sensor of this invention. (See flowchart for example.) Figure 6 As shown, the method for achieving ultra-high sensitivity in a MEMS micro-pressure sensor according to the present invention includes the following steps:
[0038] Step 1, as follows Figure 1 , 2 As shown, different magnitudes and directions of pressure are applied to the first pressure membrane 3-1 and the second pressure membrane 3-2 to induce perturbations of varying magnitudes on the first resonant beam 4-1. Under each pressure, the frequency response of the amplitudes of the first resonant beam 4-1 and the second resonant beam 4-2 is measured using a dynamic signal analyzer. By measuring the frequency response of different resonant beams (including the first resonant beam 4-1 and the second resonant beam 4-2) in the MEMS micro-pressure sensor under different pressure perturbations, the amplitude of each resonant beam in different vibration modes is obtained; for ease of description, the amplitude is expressed as x. i，j This represents the amplitude of different resonant beams j=1, 2 in the i=1st and 2nd order modes; for example: x 1，2This represents the vibration amplitude of the resonant beam 2 in the first mode.
[0039] Step 2: For the amplitudes of each resonant beam measured in Step 1 under different modes, calculate the amplitude ratio between different resonant beams j (j=1,2) in the i-th order i=1, 2 modes by division. The calculation formula is η. i，j1，j2 =x i，j1 / x i，j2 (j1≠j2); e.g., η 1，1，2 =x 1，1 / x 1，2 This represents the amplitude ratio of resonant beam 1 and resonant beam 2 in the first mode. The sign of the amplitude ratio is determined by the vibration mode of the system; specifically, if i equals 1, the calculated amplitude ratio of the first mode is positive, i.e., η. 1，j1，j2 The result is taken as positive; if i equals 2, the calculated amplitude ratio of the second-order vibration mode is negative, i.e., η 2，j1，j2 The result is negative.
[0040] Step 3: Calculate the difference between the amplitude ratios of different modes obtained in Step 2 to get the amplitude ratio difference D of the MEMS micro-pressure sensor: When the pressure on the pressure membrane is negative, D = η 1，1，2 -η 2，2，1 When the pressure on the pressure diaphragm is a positive pressure, D + =|η 2，1，2 -η 1，2，1 | When the pressure diaphragm is not under pressure, D0 = |η 1，2，1 -η 2，1，2 |
[0041] Step 4: The D obtained in Step 3 is the difference in the segmented amplitude ratio under different pressure disturbances, thus obtaining the output curve of the MEMS micro-pressure sensor based on the difference in amplitude ratio and the change in pressure disturbance. This method can realize ultra-high sensitivity detection of MEMS micro-pressure sensor.
[0042] Table 1: Structural parameters of the MEMS micro-pressure sensor of the present invention.
[0043]
[0044] The structural dimensions described in Table 1 are designed to compare the ultra-high sensitivity implementation method proposed in this invention with traditional methods, but this method is not limited to ultra-high sensitivity detection of MEMS micro-pressure sensors under this size.
[0045] Table 2 shows the amplitude ratio correlation output data obtained by the detection method of the MEMS micro-pressure sensor of the present invention, as detailed in the table below:
[0046] Table 2-1 Output when the pressure on the pressure diaphragm is negative.
[0047]
[0048]
[0049] Table 2-2 Output when the pressure on the pressure diaphragm is 0
[0050] Pressure (MPa) <![CDATA[η 1，2，1 ]]> <![CDATA[η 2，1，2 ]]> <![CDATA[D0]]> 0 1.00734 -1.00583 0.00151
[0051] Table 2-3 Output when the pressure on the pressure diaphragm is positive pressure
[0052] Pressure (MPa) <![CDATA[η 2，1，2 ]]> <![CDATA[η 1，2，1 ]]> <![CDATA[D + ]]> 0.1 -2.74113 2.88271 -5.62383 0.2 -4.59010 5.11866 -9.70876 0.3 -6.23627 7.29557 -13.53185 0.4 -7.67758 9.37954 -17.05712
[0053] Figure 7 This is a graph showing the output curve based on the characteristic frequency in the MEMS micro-pressure sensor of this invention. Figure 7 As shown in the simulation results, when the pressure is low, the characteristic frequency exhibits a significant nonlinear characteristic with increasing pressure. This indicates that when the characteristic frequency is used as the output, the response of the micro-pressure sensor in the low pressure range is not a simple linear relationship. The sensitivities calculated using the data in columns two and three of Table 3, with the characteristic frequency as the output, are 821.682 ppm / kPa and 431.340 ppm / kPa, respectively, for the first and second modes.
[0054] Table 3: Relevant data for traditional detection methods that use characteristic frequency and amplitude ratio as outputs
[0055]
[0056]
[0057] Figure 8 The graph shows the segmented amplitude ratio difference curve for achieving ultra-high sensitivity detection with a MEMS micro-pressure sensor in this invention. Figure 8 As shown, the sensitivity of the MEMS micro-pressure sensor calculated using different output methods is compared. First, the sensitivity, measured by the amplitude ratio as the output metric, is 2.138 × 10⁻⁶, obtained from the last column of data in Table 3. 4 ppm / kPa. Secondly, using the method for achieving ultra-high sensitivity proposed in this invention (segmented amplitude ratio difference) as the output, the sensitivity calculated based on the amplitude ratio-related output data obtained from steps 2 and 3 in Table 2 is 34.435 × 10⁻⁶. 6 ppm / kPa. The sensitivity obtained by this method is 41,907 times that of traditional pressure sensors that use amplitude ratio as the output, representing a significant improvement in sensitivity; at the same time, this method also exhibits good linearity in the micro-pressure region shown in the shaded area.
[0058] This invention discloses a MEMS micro-pressure sensor that employs a segmented output method, meaning that different calculation methods are used depending on the applied pressure (positive pressure, negative pressure, and no pressure). This allows for flexible selection of appropriate formulas for calculation based on the varying pressures applied to the micro-pressure sensor, effectively expanding the sensor's measurement range and improving its sensitivity. Analysis of the micro-pressure sensor in this embodiment shows that its sensitivity is five orders of magnitude higher than that of traditional resonant micro-pressure sensors, making it suitable for applications requiring high-sensitivity micro-pressure measurements, such as aerospace vehicles and intracranial pressure detection.
[0059] To address the challenge of obtaining two identical resonant beams due to processing and etching processes, this invention introduces tuning electrodes distributed across the resonant beams and utilizes the spring softening effect to achieve perfect consistency in the natural frequencies of the two beams. Through the tuning electrodes, the natural frequencies of the resonant beams can be precisely adjusted, compensating for processing errors and ensuring that the two beams possess identical frequency characteristics. This design results in improved sensor robustness, enhancing measurement accuracy while maintaining sensitivity.
[0060] The MEMS micro-pressure sensor designed in this invention has two symmetrically distributed "S"-shaped weakly coupled beams. By adjusting the length of the coupled beams, the stiffness of the coupled beams can be adjusted, thereby enabling the sensor to obtain a higher quality factor and higher sensitivity during operation.
[0061] This invention discloses an ultra-high sensitivity MEMS micro-pressure sensor. By adjusting the stiffness of the resonant beams using tuning electrodes, the natural frequencies of the two resonant beams are made equal. A higher quality factor is achieved through two symmetrically distributed "S"-shaped weakly coupled beams. Different (segmented) output methods are used to acquire the measured pressure value depending on the pressure applied to the pressure membrane (positive pressure, negative pressure, no pressure). This invention implements an ultra-high sensitivity detection method for MEMS micro-pressure sensors, offering a wide detection range, ultra-high sensitivity and accurate measurement when measuring micro-pressures, ease of use, and good stability.
[0062] The above is an exemplary description of the invention. Obviously, the specific implementation of the invention is not limited to the above-described manner. Any non-substantial improvement made using the inventive concept and technical solution of the invention, or the direct application of the inventive concept and technical solution to other situations without modification, is within the protection scope of the invention.
Claims
1. A high-sensitivity MEMS micro-pressure sensor, characterized in that, include: The base (1-1), the first resonant beam (4-1), the second resonant beam (4-2), the first weakly coupled beam (5-1), the second weakly coupled beam (5-2), and four identical first pressure membranes (3-1), second pressure membranes (3-2), third pressure membranes (3-3), and fourth pressure membranes (3-4) are disposed on the base (1-1); the two ends of the first resonant beam (4-1) are respectively fixed to the first pressure membrane (3-1) and the second pressure membrane (3-2) through the first anchor point (2-1) and the second anchor point (2-2); The second resonant beam (4-2) is fixed at both ends to the third pressure membrane (3-3) and the fourth pressure membrane (3-4) respectively via the third anchor point (2-3) and the fourth anchor point (2-4); the outer surfaces of the first resonant beam (4-1) and the second resonant beam (4-2) are respectively provided with the first tuning electrode (6-1) and the second tuning electrode (6-2); the first weak coupling beam (5-1) and the second weak coupling beam (5-2) are S-shaped structures and are symmetrically arranged between the first resonant beam (4-1) and the second resonant beam (4-2); The method for achieving ultra-high sensitivity of the MEMS micro-pressure sensor includes the following steps: Step 1: Measure the frequency response of different resonant beams in the MEMS micro-pressure sensor under different pressure disturbances, obtain the amplitude of each resonant beam in different vibration modes, and express it as x. i，j This represents the amplitude of the resonant beam j in the i-th mode; Step 2: For the amplitudes of each resonant beam measured in Step 1 under different modes, calculate the amplitude ratio between different resonant beams under the i-th mode by division. The calculation formula is η. i，j1，j2 =x i，j1 / x i，j2 (j1≠j2); When calculating the amplitude ratio, the sign is determined by the vibration mode of the system; specifically, if i equals 1, the amplitude ratio calculation result of the first vibration mode is positive, i.e., η 1，j1，j2 The result is positive. If i equals 2, then the calculated amplitude ratio of the second-order vibration mode is negative, i.e., η 2，j1，j2 The result is negative. Step 3: Calculate the difference between the amplitude ratios of different modes obtained in Step 2 to get the amplitude ratio difference D of the MEMS micro-pressure sensor: D is calculated when the pressure on the pressure membrane is negative. - =η 1，1，2 -η 2，2，1 When the pressure on the pressure diaphragm is a positive pressure, D + =η 2，1，2 -η 1，2，1 When the pressure diaphragm is not under pressure, |η 1，2，1 -η 2，1，2 |; Step 4: The D obtained from Step 3 is the difference in the segmented amplitude ratio under different pressure disturbances, thus obtaining the output curve of the MEMS micro-pressure sensor based on the difference in amplitude ratio and the change in pressure disturbance. This method can realize ultra-high sensitivity detection of MEMS micro-pressure sensor.
2. The ultra-high sensitivity MEMS micro-pressure sensor according to claim 1, wherein the first anchor point (2-1), the second anchor point (2-2), the third anchor point (2-3), and the fourth anchor point (2-4) are respectively fixed at the center of the outer side of the upper end face of the first pressure membrane (3-1), the second pressure membrane (3-2), the third pressure membrane (3-3), and the fourth pressure membrane (3-4), specifically at a position of one-quarter of the length and one-half the width of the outer side of their upper end face.
3. The ultra-high sensitivity MEMS micro-pressure sensor according to claim 1, characterized in that, The first tuning electrode (6-1) and the second tuning electrode (6-2) have the same length and width.
4. The ultra-high sensitivity MEMS micro-pressure sensor according to claim 1, characterized in that, The length of the first tuning electrode (6-1) is less than the length of the first resonant beam (4-1); the width and height of the first tuning electrode (6-1) are equal to the width and height of the first resonant beam (4-1), respectively; the length of the second tuning electrode (6-2) is less than the length of the second resonant beam (4-2); the width and height of the second tuning electrode (6-2) are equal to the width and height of the second resonant beam (4-2), respectively.