Symmetrical clamped micro-beam electric power sensing device based on MEMS resonator

Abstract

The invention provides a symmetrical clamped micro-beam electric power sensing device based on MEMS resonators, and belongs to the technical field of MEMS sensing. The sensing device comprises a sensing assembly. The sensing assembly comprises a vibration beam, an excitation electrode, a tuning electrode and an auxiliary electrode. The two ends of the vibration beam in the axial direction of the vibration beam are connected with the auxiliary electrodes, and the exciting electrodes and the tuning electrodes are arranged at intervals in the length direction of the vibration beam and arranged on the same side of the vibration beam. Excitation voltage is applied to the excitation electrode so that the excitation electrode can excite the vibration beam to generate resonance. Tuning voltage is applied to the tuning electrode so that the tuning electrode can adjust the rigidity of the vibration beam according to the environment temperature, and the thermal power corresponding to the heat source can be inverted. The two sensing assemblies are arranged in a central symmetry mode, so that interference of electrostatic fields generated by the excitation electrodes and the tuning electrodes corresponding to different vibration beams can be weakened mutually. According to the invention, high-precision power inversion in a wide temperature range can be realized.

Description

Technical Field

[0001] This invention relates to the field of microelectromechanical systems (MEMS) sensing technology, and in particular to a symmetrical fixed-support microbeam power sensing device based on a MEMS resonator. Background Technology

[0002] With the rapid development of microelectronic systems towards miniaturization, high integration, and low power consumption, power sensing, as a core technology for energy efficiency management and fault diagnosis of electronic devices, places stringent requirements on the size, accuracy, and anti-interference capabilities of sensors. Although traditional quartz crystal resonators have high frequency stability, they suffer from inherent defects due to limitations in material properties and processing technology, such as poor compatibility with CMOS processes, difficulty in miniaturization and integration, and sensitivity to vibration and temperature. These limitations make them unable to meet the dynamic monitoring needs of smart terminals, IoT devices, and automotive electronics.

[0003] Micro-Electro-Mechanical Systems (MEMS) resonators, with their advantages of small size, low power consumption, and ease of system integration, have become a core solution to replace quartz devices, demonstrating great potential in the field of physical quantity sensing. However, existing MEMS resonators still face three major technical bottlenecks in electrical power measurement applications: significant feedthrough effect, severe temperature drift, and nonlinear response.

[0004] To address these issues, related technologies have attempted to improve performance by optimizing electrode shape, employing high-dielectric materials, or introducing complex feedback circuits. However, these approaches suffer from drawbacks such as high cost, complex manufacturing processes, or limited applicability. For instance, while increasing the electromechanical coupling area in traditional designs can improve signal strength, it exacerbates feedthrough interference. Furthermore, solutions relying solely on algorithms to compensate for temperature drift struggle to achieve real-time calibration in dynamic power measurement scenarios. Therefore, developing a MEMS power sensing technology that combines low feedthrough characteristics, wide-temperature-range self-calibration capabilities, and structural stability is crucial for overcoming existing technological bottlenecks. Summary of the Invention

[0005] This invention provides a symmetrical fixed microbeam electric power sensing device based on a MEMS resonator, the purpose of which is to achieve high-precision power inversion over a wide temperature range.

[0006] To achieve the above objectives, this invention provides a symmetrically fixed microbeam electrical power sensing device based on a MEMS resonator, comprising a sensing component. The sensing component includes a vibrating beam, an excitation electrode, a tuning electrode, and an auxiliary electrode. The auxiliary electrode is connected to both ends of the vibrating beam along its axial direction. The excitation electrode and the tuning electrode are spaced apart along the length of the vibrating beam and are both located on the same side of the vibrating beam. An excitation voltage is applied to the excitation electrode to excite the vibrating beam to resonate. A tuning voltage is applied to the tuning electrode to adjust the stiffness of the vibrating beam according to the ambient temperature, thereby retrieving the thermal power corresponding to the heat source. The number of sensing components is two, and the two sensing components are arranged centrally symmetrically so that the interference of electrostatic fields generated by the excitation electrode and the tuning electrode corresponding to different vibrating beams can mutually weaken each other.

[0007] In one embodiment, the auxiliary electrode is subjected to a tuning voltage so that the interference of the electrostatic fields generated by the excitation electrode and the tuning electrode corresponding to different vibration beams can mutually weaken each other.

[0008] In one embodiment, the sensing device includes a detection component, which includes an output electrode and a network analyzer that are electrically connected. The output electrode is disposed between two of the sensing components and is capable of detecting the difference in vibration frequencies of the two vibrating beams and converting the difference into an electrical signal that is transmitted to the network analyzer. When the difference exceeds a threshold, the tuning voltage of the tuning electrode is adjusted.

[0009] In one embodiment, there are multiple output electrodes, which are arranged at intervals along the axial direction of the vibrating beam.

[0010] In one embodiment, the detection component includes an amplifier disposed between the network analyzer and the output electrode and electrically connected to both the network analyzer and the output electrode, to amplify the electrical signal of the output electrode and output it to the network analyzer.

[0011] In one embodiment, when the ambient temperature is 20°C, the relationship between the resonant frequency of the vibrating beam and the tuning voltage of the tuning electrode is Y = -4.8247X + 147.7833; when the ambient temperature is 40°C, the relationship between the resonant frequency of the vibrating beam and the tuning voltage of the tuning electrode is Y = -5.5579X + 146.4446, to calibrate the relationship curve between the tuning voltage of the tuning electrode and the thermal power of the heat source, where Y is the resonant frequency of the vibrating beam and X is the square of the tuning voltage of the tuning electrode.

[0012] In one embodiment, when the ambient temperature is 20°C, the tuning voltage of the auxiliary electrode varies from 0V to 6.2V; when the ambient temperature is 40°C, the tuning voltage of the auxiliary electrode varies from 0V to 5.8V.

[0013] In one embodiment, the geometric center of the auxiliary electrode is located on the extension of the central axis of the vibrating beam.

[0014] The above-described solution of the present invention has the following beneficial effects:

[0015] In this embodiment, the excitation electrode can induce resonance in the vibrating beam. When the ambient temperature changes, i.e., the electrical power of the electronic device to which the sensing component is attached changes, the stiffness of the vibrating beam changes. The stiffness of the vibrating beam can then be adjusted by the tuning electrode. Based on this, there is a corresponding relationship between the tuning voltage of the tuning electrode and the electrical power of the electronic device. The electrical power of the electronic device can be inverted through the tuning voltage, thus enabling the sensing device of this application to acquire the electrical power of the electronic device. The electrostatic field generated by multiple electrodes in the sensing component generates parasitic capacitance and current in the vibrating beam, resulting in spurious signals. By arranging the two sensing components centrally symmetrically and applying the same excitation and tuning voltages to the corresponding excitation and tuning electrodes, the spurious signals generated by the electrodes in the two sensing components can weaken each other, thereby improving the suppression of common-mode feedthrough effects. Compared to a single microbeam design, which is difficult to resist external interference, the two centrally symmetrically arranged sensing components reduce the nonlinear response of the vibrating beam, improve the stability of the mapping relationship between the tuning voltage and the vibration frequency of the vibrating beam, and thus improve the accuracy of the electrical power inversion of the electronic device.

[0016] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the sensing component and the output electrode in one embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of a sensing device in one embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the three-dimensional deflection distribution of a vibrating beam in one embodiment of the present invention;

[0020] Figure 4 This is a curve showing the relationship between the calibrated thermal power and the tuning voltage of the tuning electrode when the ambient temperature is 20°C, according to one embodiment of the present invention.

[0021] Figure 5This is a curve showing the relationship between the calibrated thermal power and the tuning voltage of the tuning electrode when the ambient temperature is 40°C, according to one embodiment of the present invention.

[0022] [Explanation of Labels in the Attached Image]

[0023] 1. Sensing component; 11. Vibrating beam; 12. Excitation electrode; 13. Tuning electrode; 14. Auxiliary electrode; 2. Detection component; 21. Output electrode; 22. Network analyzer; 23. Amplifier; 24. Phase shifter. Detailed Implementation

[0024] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] In related technologies, spurious signals caused by parasitic capacitance between electrodes can mask the true resonant signal, resulting in spectral distortion and significant feedthrough effects. Traditional methods of compensation via back-end circuits not only increase system complexity but also introduce additional power consumption. The mechanical properties of silicon-based materials change with temperature, causing resonant frequency shifts. In a wide temperature range of 20℃-40℃, uncalibrated measurement errors can reach over 5%, indicating a severe impact from temperature drift. Furthermore, the nonlinear response caused by structural asymmetry makes it difficult for a single microbeam design to counteract external interference, leading to insufficient stability in the mapping relationship between tuning voltage and frequency, thus limiting the accuracy of power inversion.

[0028] In view of this, this application, based on symmetrical structural design and differential detection principle, suppresses common-mode feedthrough signals at the structural level through the coordinated optimization of centrally symmetrical sensing components and various electrodes; combined with a temperature-voltage-frequency multidimensional calibration model, it achieves high-precision power inversion over a wide temperature range, providing an innovative solution for power monitoring of microelectronic devices.

[0029] Specifically, please refer to Figure 1 and Figure 2 This application provides a symmetrically fixed microbeam electrical power sensing device based on a MEMS resonator. The sensing device includes a sensing component 1. The sensing component 1 can be attached to the heat source of an electronic device using thermally conductive adhesive to monitor the electrical power of the electronic device. The electronic device can be a small-sized smart wearable device. The thermal conductivity of the thermally conductive adhesive is greater than 1.5 W / (m²). K).

[0030] Please see Figure 1 The sensing component 1 includes a vibrating beam 11, an excitation electrode 12, a tuning electrode 13, and an auxiliary electrode 14.

[0031] Both ends of the vibrating beam 11 along its axial direction are connected to auxiliary electrodes 14. For example, both ends of the vibrating beam 11 along its axial direction are fixedly connected to the auxiliary electrodes 14. The sensing component 1 also includes a substrate, on which the auxiliary electrodes 14 are disposed, so that the vibrating beam 11 is suspended above the substrate. The substrate can be SOI (Silicon-On-Insulator), where a buried oxide layer is embedded between the top of the silicon substrate and the base layer to achieve dielectric isolation of the components. This technology can reduce parasitic capacitance, increase operating speed, and reduce power consumption.

[0032] The excitation electrode 12 and the tuning electrode 13 are arranged at intervals along the length of the vibrating beam 11, and both are located on the same side of the vibrating beam 11, for example, on one side of the vibrating beam 11 along its thickness. An excitation voltage is applied to the excitation electrode 12 so that the excitation electrode 12 can excite the vibrating beam 11 to resonate. Figure 3As shown. The excitation voltage is an AC voltage, which can be provided by the phase shifter 24. The excitation electrode 12 drives the vibration beam 11 to vibrate mainly by changing the mechanical vibration characteristics of the vibration beam 11 through electrostatic force, which is commonly used in the design of microelectromechanical systems (MEMS) devices such as accelerometers and gyroscopes. The resonant frequency of the vibration beam 11 is an inherent property of the vibration beam 11 and can be obtained by measurement. When the frequency of the excitation voltage is equal to the resonant frequency of the vibration beam 11, the vibration beam 11 can be excited to resonate. A tuning voltage is applied to the tuning electrode 13 so that the tuning electrode 13 can adjust the stiffness of the vibration beam 11 according to the ambient temperature to reflect the heat power corresponding to the heat source. The tuning voltage is a DC voltage. The tuning voltage applied to the tuning electrode 13 can generate an electrostatic field and generate an electrostatic attraction on the vibration beam 11, thereby controlling the equivalent stiffness of the vibration beam 11. When the ambient temperature of sensing component 1 changes, i.e., the electrical power of the heat source of the electronic device corresponding to the sensing device changes, the stiffness of the vibrating beam 11 changes accordingly. The stiffness of the vibrating beam 11 is then changed again by the tuning electrode 13, so that the vibrating beam 11 can still resonate under the excitation of the excitation electrode 12. Based on this, there is a corresponding relationship between the tuning voltage of the tuning electrode 13 and the electrical power of the electronic device, and the electrical power of the electronic device can be inferred from the tuning voltage of the tuning electrode 13.

[0033] There are two sensing components 1, which are arranged centrally symmetrically to reduce the interference of electrostatic fields generated by the excitation electrodes 12 and tuning electrodes 13 corresponding to different vibrating beams 11. When the two sensing components 1 are arranged centrally symmetrically, and the excitation voltage and tuning voltage applied to the two sensing components 1 are equal, the electrostatic fields generated by the excitation electrodes 12 and tuning electrodes 13 corresponding to the two sensing components 1 have equal amplitudes and opposite polarities. This allows the interference of the electrostatic fields generated by each electrode on the resonant signal of the vibrating beam 11 to be reduced, thereby suppressing the common-mode feedthrough effect.

[0034] In this embodiment, the excitation electrode 12 can excite the vibrating beam 11 to resonate. When the ambient temperature changes, i.e., the electrical power of the electronic device attached to the sensing component 1 changes, the stiffness of the vibrating beam 11 changes, and then the stiffness of the vibrating beam 11 is adjusted by the tuning electrode 13. Based on this, there is a corresponding relationship between the tuning voltage of the tuning electrode 13 and the electrical power of the electronic device. The electrical power of the electronic device can be inferred from the tuning voltage, thereby enabling the sensing device of this application to acquire the electrical power of the electronic device. The electrostatic field generated by the multiple electrodes in the sensing component 1 generates parasitic capacitance and current in the vibrating beam 11, which in turn generates spurious signals. By symmetrically arranging the two sensing components 1 and passing the same excitation voltage and tuning voltage through the corresponding excitation electrode 12 and tuning electrode 13, the spurious signals generated by the electrodes in the two sensing components 1 can weaken each other, thereby improving the effect of suppressing the common-mode feedthrough effect. The two centrally symmetrically arranged sensing components 1, compared to a single microbeam design which is difficult to resist external interference, reduce the nonlinear response of the vibrating beam 11, improve the stability of the mapping relationship between the tuning voltage and the vibration frequency of the vibrating beam 11, and thus improve the power inversion accuracy of the electronic device.

[0035] In one embodiment, please refer to Figure 1 A tuning voltage is applied to the auxiliary electrode 14 to further weaken the interference of the electrostatic fields generated by the excitation electrode 12 and tuning electrode 13 corresponding to different vibrating beams 11. It should be noted that, relying solely on the centrally symmetrical arrangement of the excitation electrode 12 and tuning electrode 13 in different sensing components 1, residual parasitic capacitance will still exist at the edge position of the vibrating beam 11 along its own axis. By applying a tuning voltage to the auxiliary electrodes 14 at both ends of the vibrating beam 11 along its own axis, the symmetrically arranged auxiliary electrodes 14 can suppress the residual parasitic capacitance a second time, and at the same time help maintain the frequency difference stability of the two vibrating beams 11 (due to the manufacturing process of the vibrating beams 11, the stiffness of the two vibrating beams 11 will not be completely equal), which is beneficial to achieving full-dimensional feedthrough suppression.

[0036] In one embodiment, please refer to Figure 1 and Figure 2 The sensing device includes a detection component 2, which comprises an output electrode 21 electrically connected to a network analyzer 22. The output electrode 21 is positioned between the two sensing components 1. The output electrode 21 detects the difference in vibration frequencies between the two vibrating beams 11 and converts this difference into an electrical signal, which is then transmitted to the network analyzer 22. When the difference exceeds a threshold, the tuning voltage of the tuning electrode 13 is adjusted. Based on the differential detection principle, the output electrode 21 can compare the common signals (vibration frequencies) of the two vibrating beams 11, filter out common interference, and extract useful differences. When the difference in the resonant frequencies of the two vibrating beams 11 exceeds a threshold, further calibration is required.

[0037] In one embodiment, please refer to Figure 1 and Figure 2 The number of output electrodes 21 is multiple, and the multiple output electrodes 21 are arranged at intervals along the axial direction of the vibrating beam 11. For example, the number of output electrodes 21 can be... Figure 1 The three output electrodes 21 are arranged at even intervals, forming a symmetrical structure. The output electrode 21 located in the middle facilitates the acquisition of signals from the surrounding electrodes. The three output electrodes 21 can form multiple sets of differential signal pairs, which helps to improve the calculation accuracy of the difference in resonant frequencies between the two vibrating beams 11.

[0038] In one embodiment, please refer to Figure 2 The detection component 2 includes an amplifier 23, which is disposed between the network analyzer 22 and the output electrode 21 and is electrically connected to the network analyzer 22 and the output electrode 21 respectively, so as to amplify the electrical signal of the output electrode 21 and output it to the network analyzer 22, thereby enabling the network analyzer 22 to analyze the difference in vibration frequency between the two vibrating beams 11 in real time.

[0039] In one embodiment, such as Figure 4 As shown, when the ambient temperature is 20℃, the relationship between the resonant frequency of the vibrating beam 11 and the tuning voltage of the tuning electrode 13 is Y = -4.8247X + 147.7833. Figure 5 As shown, when the ambient temperature is 40℃, the relationship between the resonant frequency of the vibrating beam 11 and the tuning voltage of the tuning electrode 13 is Y = -5.5579X + 146.4446, which is used to calibrate the tuning voltage of the tuning electrode 13, and then calibrate the relationship curve between the tuning voltage of the tuning electrode 13 and the heat power of the heat source, so as to reduce the influence of the resonant frequency shift caused by the temperature change of the silicon-based material. In the formula, Y is the resonant frequency of the vibrating beam 11, and X is the square of the tuning voltage of the tuning electrode 13.

[0040] In one embodiment, when the ambient temperature is 20°C, the tuning voltage of the auxiliary electrode 14 varies from 0V to 6.2V; when the ambient temperature is 40°C, the tuning voltage of the auxiliary electrode 14 varies from 0V to 5.8V. Adjusting the tuning voltage of the auxiliary electrode 14 effectively suppresses residual parasitic capacitance, which improves the stability and anti-interference capability of the tuning electrode 13 in controlling the stiffness of the vibrating beam 11. In actual measurements, the vibration frequency of the vibrating beam 11 is precisely controlled by adjusting the tuning voltage of the tuning electrode 13, thereby retrieving the electrical power of the electronic equipment.

[0041] In one embodiment, the geometric center of the auxiliary electrode 14 is located on the extension line of the central axis of the vibration beam 11, so that the auxiliary electrode 14 and the vibration beam 11 are symmetrical in multiple directions, which is beneficial for secondary suppression of residual parasitic capacitance.

[0042] The sensing device of this application will be described in detail below with reference to an embodiment.

[0043] Select the matching Figure 1 The polycrystalline silicon vibrating beam 11, fixed at both ends to auxiliary electrodes 14, has the following geometric dimensions: length 400μm±0.5μm, height 25μm±0.2μm, width 3μm±0.1μm, and is suspended 2μm±0.1μm above the SOI substrate. The relative deviation between the electrodes corresponding to the two vibrating beams 11 is ≤0.5μm (ensuring one-time molding using the same photomask). The contact pads formed by sputtering a gold layer (thickness 50nm±5nm) on the surface of the vibrating beam 11 are tested using a probe station. The contact resistance difference between the two vibrating beams 11 is required to be ≤0.2Ω, the overall contact resistance ≤5Ω, and the initial resistance value within the range of 996±5Ω.

[0044] Please see Figure 1 The sensing component 1 is attached to the hot end of the electronic device (such as the heat-generating area of ​​the chip) using thermally conductive adhesive (thermal conductivity ≥1.5W / (m・K)), ensuring that the contact area between the sensing component 1 and the hot end is ≥95%. Nitrogen gas (purity ≥99.99%) is introduced into the test chamber (the chamber used for testing the sensing component 1) and baked at 80℃ for 2 hours to remove the water vapor adsorbed on the surface of the vibrating beam 11 (to avoid contact resistance drift caused by water vapor). After baking, the surface is allowed to cool naturally to room temperature (25℃±1℃), and the resistance of the two vibrating beams 11 is tested again. The deviation must be ≤3Ω.

[0045] Initial symmetry calibration is performed on the two vibrating beams 11. An initial DC voltage (0.5V ± 0.001V) is applied to the tuning electrodes 13 corresponding to the two vibrating beams 11, with a voltage difference ≤ 1mV; through... Figure 2 The network analyzer 22 (sampling rate 1kHz, resolution 0.01kHz) in the middle acquires the resonant frequencies of the two vibrating beams 11 respectively, and adjusts the tuning voltage of the two tuning electrodes 13 so that the initial frequency difference of the two vibrating beams 11 is ≤0.5kHz, thus completing the establishment of the symmetrical reference.

[0046] Establish a calibration link. Place the sensing component 1 in a precision temperature chamber (temperature control accuracy ±0.05℃). Place a standard power source (error ±0.1%) and a thermistor (temperature measurement accuracy ±0.1℃) inside the temperature chamber. Connect the output terminal of the standard power source in series with the power supply terminal of the hot end of the electronic device to calibrate the mapping relationship between the vibration frequency of the vibration beam 11 and the electrical power of the electronic device.

[0047] Calibration under 20℃ operating conditions. Set the chamber temperature to 20℃ and maintain it for 30 minutes (ensuring the temperature of sensor component 1 is stable); adjust... Figure 1The tuning voltage applied to the auxiliary electrode 14 is increased from 0V to 6.2V in steps of 0.1V, with the tuning voltage deviation between the two auxiliary electrodes 14 kept ≤0.1V at each step (based on...). Figure 1 The symmetrical electrode gap design cancels common-mode feedthrough. In each step, after the tuning voltage stabilizes for one minute, the... Figure 2 The network analyzer 22 and amplifier 23 (low-noise amplifier 23 with a gain of 10 times, bandwidth of 1kHz-1MHz, and bandpass filter center frequency of 75-150kHz) recorded the average resonant frequencies of the two vibrating beams 11, and fitted the 20℃ calibration curve: Y = -4.8247X + 147.7833 (where Y is the frequency in kHz; X is the square of the voltage in V). 2 The power factor K1 was simultaneously calibrated to 0.085mW / (kHz) using a standard power source. V 2 The frequency measurement error caused by feedthrough interference is ≤0.3kHz.

[0048] Calibration under 40℃ operating conditions. The chamber temperature was set to 40℃ and held for 30 minutes. The tuning voltage applied to the auxiliary electrode 14 was adjusted, increasing from 0V in 0.1V increments to 5.8V. The signal acquisition and fitting process was repeated to obtain the 40℃ calibration curve: Y = -5.5579X + 146.4446, with a calibration power coefficient K2 = 0.092mW / (kHz). V 2 );use Figure 1 The temperature drift mutual compensation effect of the symmetrical vibration beam 11 reduces the calibration error to ±0.5%, and the two calibration curves and the corresponding K values ​​are stored.

[0049] Measurement environment preparation. Remove the temperature chamber and place the sensor in the actual working environment (temperature 20℃-40℃, relative humidity ≤60%), ensuring that the hot end of the electronic equipment is powered normally; start amplifier 23 and network analyzer 22, set the signal sampling period to 0.5 seconds, maintain the gain of low noise amplifier 23 at 10 times, and keep the bandpass filter parameters unchanged.

[0050] Feedthrough suppression tuning. Call the calibration curve corresponding to the current ambient temperature (e.g., when the ambient temperature is 28℃, use linear interpolation to correct the parameters of the 20℃ and 40℃ curves); adjust the tuning voltage applied to the auxiliary electrode 14 to the target voltage (e.g., 3.5V), while simultaneously fine-tuning the tuning voltage of the tuning electrode 13 (difference ≤ 1mV), relying on... Figure 1The electrostatic field coupling cancellation effect of each symmetrical electrode suppresses the common-mode feedthrough signal to below -70dBm, with a feedthrough rejection ratio ≥60dB. The frequency difference between the two vibrating beams 11 is monitored in real time and controlled to be ≤0.1%. At this time, the temperature drift mutual compensation effect of the two symmetrical vibrating beams 11 is activated, and the frequency drift deviation is reduced by more than 60%.

[0051] Differential frequency detection and power inversion. Figure 2 The output electrode 21 collects the resonant frequency signals of the two vibrating beams 11, and subtracts the resonant frequency signals of the two vibrating beams 11 to obtain the frequency difference Δf (error ≤ 0.05kHz). After filtering out environmental noise, the effective frequency value Y of the output tuning voltage is output. Substituting it into the calibration curve corresponding to the current temperature, the square of the tuning voltage is calculated (e.g., at 20℃, X = (147.7833-Y) / 4.8247). Combined with the power coefficient K, the power of the electronic device can be calculated. The formula for the power P is: P = X × K (e.g., when Y = 104.36kHz, X = (3V)). 2 =9V 2 P = 9 × 0.085 = 0.765mW); the power result can be output through the relevant display device (unit: mW, resolution: 0.01mW). After every 5 measurements, the feedthrough suppression tuning is automatically repeated to avoid feedthrough interference rise caused by long-term operation.

[0052] Measurement accuracy verification. Three typical power points (e.g., 0.5mW, 3mW, and 6mW) were selected and applied to the hot end of the electronic device using a standard power source. The measurement was performed using the method described in this embodiment, and the results are as follows:

[0053] The verification results show that, relying on Figure 1 The low feedthrough effect of the symmetrical structure and Figure 2 The differential calibration link in this embodiment maintains a stable measurement accuracy within ±1.2% in the 20℃-40℃ range, with a feedthrough rejection ratio ≥60dB, meeting the power monitoring requirements of electronic equipment.

[0054] In summary, this application utilizes a symmetrical fixed-support vibrating beam 11 structure based on a MEMS resonator. By adjusting the tuning voltage, the resonant frequency difference between the two vibrating beams 11 is ≤0.1%, and a calibration relationship of "tuning voltage-resonant frequency-temperature" is established. Based on this pre-stored calibration relationship, the frequency matching state of the vibrating beams 11 is maintained, achieving high-precision electrical power measurement. This invention effectively solves the problems of insufficient frequency matching accuracy and temperature drift sensitivity in traditional single / dual voltage tuning schemes, and is expected to be applied in fields such as power monitoring.

[0055] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A symmetrically fixed microbeam power sensing device based on a MEMS resonator, characterized in that, The system includes a sensing assembly comprising a vibrating beam, an excitation electrode, a tuning electrode, and an auxiliary electrode. The auxiliary electrode is connected to both ends of the vibrating beam along its axial direction. The excitation electrode and the tuning electrode are spaced apart along the length of the vibrating beam and are both located on the same side of the vibrating beam. An excitation voltage is applied to the excitation electrode to induce resonance in the vibrating beam. A tuning voltage is applied to the tuning electrode to adjust the stiffness of the vibrating beam according to the ambient temperature, thereby retrieving the thermal power corresponding to the heat source. Two sensing assemblies are arranged centrally symmetrically to mutually weaken the interference of electrostatic fields generated by the excitation electrode and the tuning electrode corresponding to different vibrating beams.

2. The symmetrically fixed microbeam power sensing device based on a MEMS resonator according to claim 1, characterized in that, The auxiliary electrode is subjected to a tuning voltage so that the interference of the electrostatic fields generated by the excitation electrode and the tuning electrode corresponding to different vibration beams can be mutually weakened.

3. The symmetrically fixed microbeam power sensing device based on a MEMS resonator according to claim 1, characterized in that, The sensing device includes a detection component, which includes an output electrode and a network analyzer that are electrically connected. The output electrode is disposed between two of the sensing components. The output electrode can detect the difference in vibration frequencies of the two vibrating beams and convert the difference into an electrical signal that is transmitted to the network analyzer. When the difference exceeds a threshold, the tuning voltage of the tuning electrode is adjusted.

4. The symmetrically fixed microbeam power sensing device based on a MEMS resonator according to claim 3, characterized in that, The number of output electrodes is multiple, and the multiple output electrodes are arranged at intervals along the axial direction of the vibrating beam.

5. The symmetrically fixed microbeam power sensing device based on a MEMS resonator according to claim 3, characterized in that, The detection component includes an amplifier disposed between the network analyzer and the output electrode and electrically connected to both the network analyzer and the output electrode, so as to amplify the electrical signal of the output electrode and output it to the network analyzer.

6. The symmetrically fixed microbeam power sensing device based on a MEMS resonator according to any one of claims 1 to 5, characterized in that, When the ambient temperature is 20℃, the relationship between the resonant frequency of the vibrating beam and the tuning voltage of the tuning electrode is Y = -4.8247X + 147.7833. When the ambient temperature is 40℃, the relationship between the resonant frequency of the vibrating beam and the tuning voltage of the tuning electrode is Y = -5.5579X + 146.4446, in order to calibrate the relationship curve between the tuning voltage of the tuning electrode and the heat power of the heat source, where Y is the resonant frequency of the vibrating beam and X is the square of the tuning voltage of the tuning electrode.

7. The symmetrically fixed microbeam power sensing device based on a MEMS resonator according to claim 6, characterized in that, When the ambient temperature is 20°C, the tuning voltage of the auxiliary electrode varies from 0V to 6.2V; when the ambient temperature is 40°C, the tuning voltage of the auxiliary electrode varies from 0V to 5.8V.

8. The symmetrically fixed microbeam power sensing device based on a MEMS resonator according to any one of claims 1 to 5, characterized in that, The geometric center of the auxiliary electrode is located on the extension of the central axis of the vibrating beam.

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