A dual-path signal sensor based on modal localization effect

Abstract

The present invention discloses a dual-path signal sensor based on modal localization effect, belonging to the field of MEMS sensors. The sensor includes a resonator 1 101, a resonator 2 102, a resonator 3 103, and the three resonators are arranged at the three vertices of an equilateral triangle, the resonator 1 101 is connected to the resonator 2 102 through a coupling beam 104, the resonator 2 102 is connected to the resonator 3 103 through a coupling beam 2 105, and the resonator 3 103 is connected to the resonator 1 101 through a coupling beam 3 106, and the three coupling beams 1 104, the coupling beam 2 105 and the coupling beam 3 106 are exactly the same, so as to realize the mutual coupling of the three resonators. The beneficial effect of the present invention is: to provide a dual-path signal sensor based on the modal localization effect. The invention designs a weakly coupled resonance system, which includes three mutually coupled resonators, and adopts a fixed AC driving frequency to perform a driving detection scheme for amplitude detection. Compared with the traditional modal localization sensor, the present invention can realize the simultaneous detection of dual-path signals.

Description

Technical Field

[0001] The invention discloses a dual-path signal sensor based on modal localization effect, belonging to the field of MEMS sensors. Background Art

[0002] Sensor technology plays a very important role in modern science and technology and is one of the three pillars of modern information technology. MEMS (Micro-Electro-Mechanical System) sensors have become one of the main development trends of sensors due to their many advantages such as miniaturization, excellent performance, low cost and mass production.

[0003] The modal localization sensor is a new type of MEMS sensor. Its basic principle is that the external signal interferes with the resonant system through the signal input electrode, breaking the energy balance of the system and redistributing the energy between the resonators, which is manifested as a change in the vibration amplitude of the resonator. The modal localization sensor has high sensitivity and good noise suppression ability, and is widely used in the precise measurement of various signals, such as high-resolution magnetometers, accelerometers, electrometers, etc.

[0004] Existing modal localization sensors are limited to measuring one signal and cannot measure two signals at the same time. The simultaneous detection of two signals is beneficial to the development of new sensors, such as dual-axis accelerometers, electrical multimeters, etc. The present invention proposes a dual-signal sensor based on the modal localization effect, which can realize the simultaneous detection of two signals by one sensor. Summary of the invention

[0005] The purpose of the present invention is to provide a dual-path signal sensor based on modal localization effect (hereinafter referred to as dual-path signal sensor), which is based on the modal localization effect of a three-degree-of-freedom weakly coupled resonant system and senses external signals through the amplitude of three resonators. Its main structure includes: a weakly coupled resonant system and an electrode part.

[0006] The weakly coupled resonant system has a model such as Figure 1 As shown, it includes a resonator 1 101, a resonator 2 102, a resonator 3 103, a coupling beam 1 104, a coupling beam 2 105 and a coupling beam 3 106, and the three resonators are respectively connected to fixed anchor points. It is characterized in that the resonator 1 101 is connected to the resonator 2 102 through the coupling beam 1 104, the resonator 2 102 is connected to the resonator 3 103 through the coupling beam 2 105, and the resonator 3 103 is connected to the resonator 1 101 through the coupling beam 3 106, and the three coupling beams 1 104, the coupling beam 2 105 and the coupling beam 3 106 are exactly the same, so that the three resonators are coupled to each other.

[0007] The present invention provides a typical specific structural form of the dual-path signal sensor. Figure 2 As shown, the dual-path signal sensor includes three resonators with completely identical structural parameters, namely, resonator 1 201, resonator 2 202 and resonator 3 203. The three resonators are distributed in an equilateral triangle, and the resonators are interconnected by coupling beam 1 204, coupling beam 2 205 and coupling beam 3 206 with completely identical structural parameters, and the ratio of the coupling stiffness of the coupling beam to the stiffness of the resonator is not higher than 1:100. The three resonators are respectively fixed by anchor point 1 207, anchor point 208 and anchor point 3 209, and a DC bias voltage is applied to the resonator through the anchor points. There are AC driving electrodes 210, 211 and 212 at a certain gap outside the resonator. The AC driving electrodes and the anchor points apply a driving force to the entire weakly coupled resonant system, causing the resonator to vibrate in simple harmonic motion. At a certain gap outside the three resonators, there are detection electrodes 1 213, 214 and 215, which respectively detect the amplitudes of resonator 1 201, resonator 2 202 and resonator 3 203. At a certain gap outside the resonator 2 202, there is a signal input electrode 1 216, and at a certain gap outside the resonator 2 202, there is a signal input electrode 2 217, which introduces external signals.

[0008] Without considering the influence of damping, the above weakly coupled resonant system is transformed into a mass-spring equivalent model. Figure 3 As shown, the system consists of an equivalent resonator 1 301, an equivalent resonator 2 302, an equivalent resonator 3 303, an equivalent coupling beam 1 304, an equivalent coupling beam 2 305 and an equivalent coupling beam 306. The equivalent resonator 1 301 consists of an equivalent stiffness 1 307 and an equivalent mass 1 308, the equivalent resonator 2 302 consists of an equivalent stiffness 2 309 and an equivalent mass 2 310, and the equivalent resonator 3 303 consists of an equivalent stiffness 3 311 and an equivalent mass 3 312. k1, k2 and k3 represent the equivalent stiffness of resonator 1 201, resonator 2 202 and resonator 203, respectively; m1, m2 and m3 represent the equivalent mass of the equivalent resonator 1 301, the equivalent resonator 2 302 and the equivalent resonator 3 303, respectively; k c Represents the coupling stiffness. The three resonators have the same structural parameters, namely k1=k2=k3=k, m1=m2=m3=m. According to the dynamic equation, we can get:

[0009]

[0010] The resonator performs simple harmonic vibration, and the simple harmonic vibration equation is Substituting into formula (1) we can get:

[0011]

[0012] It can be seen from equation group (2) that the dynamic equations of the three resonators are similar in form, and any two of the equations can eliminate an amplitude quantity A. Stiffness disturbances Δk1 and Δk2 are input to resonator 1 201 and resonator 2 202 respectively through signal input electrodes 216 and 217, and the amplitude ratios A3 / A1 and A3 / A2 are calculated. The results are as follows:

[0013]

[0014] As shown in equation group (3), when the AC driving frequency is kept constant, the amplitude ratio A3 / A1 is linearly related to the input disturbance Δk1 of the resonator 1 201; the amplitude ratio A3 / A2 is linearly related to the input disturbance Δk2 of the resonator 2 202. In summary, the simultaneous detection of dual-path signals is achieved through two independent amplitude ratio detections.

[0015] The beneficial effect of the present invention is to provide a dual-path signal sensor based on the modal localization effect. The invention designs a weakly coupled resonance system, which includes three mutually coupled resonators and adopts a drive detection scheme for amplitude detection with a fixed AC drive frequency. Compared with the traditional modal localization sensor, the present invention can realize the simultaneous detection of dual-path signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an equivalent schematic diagram of the weakly coupled resonance system designed by the present invention.

[0017] In the figure, 101 is resonator one, 102 is resonator two, 103 is resonator three, 104 is coupling beam one, 105 is coupling beam two, and 106 is coupling beam three.

[0018] Figure 2 It is a typical structural schematic diagram of the dual-path signal sensor designed by the present invention.

[0019] In the figure, 201 is resonator one, 202 is resonator two, 203 is resonator three, 204 is coupling beam one, 205 is coupling beam two, 206 is coupling beam three, 207 is anchor point one, 208 is anchor point two, 209 is anchor point three, 210 is AC drive electrode one, 211 is AC drive electrode two, 212 is AC drive electrode three, 213 is detection electrode one, 214 is detection electrode two, 215 is detection electrode three, 216 is signal input electrode one, and 217 is signal input electrode two.

[0020] Figure 3 It is a schematic diagram of the spring-mass equivalent model of a weakly coupled resonant system.

[0021] In the figure, 301 is the equivalent resonator one, 302 is the equivalent resonator two, 303 is the equivalent resonator three, 304 is the equivalent coupling beam one, 305 is the equivalent coupling beam two, 306 is the equivalent coupling beam three, 307 is the equivalent stiffness one, 308 is the equivalent stiffness two, 309 is the equivalent stiffness three, 310 is the equivalent mass one, 311 is the equivalent mass two, and 312 is the equivalent mass three.

[0022] Figure 4 This is the working mode simulation result of the dual-path sensor designed by the present invention.

[0023] Figure 5 It is the simulation result of the output amplitude ratio of the dual-path signal sensor changing with the input signal when the two-path signals are input from the signal input electrode 1 216 and the signal input electrode 2 217 respectively.

[0024] Figure 6 The diagram is a schematic diagram of some specific feasible structures of the weak coupling resonance system designed by the present invention. The weak coupling resonance system includes but is not limited to the several structures shown in the figure. DETAILED DESCRIPTION

[0025] according to Figure 2 The typical structure shown provides a dual-path signal sensor. The material of all structures is silicon, and the three resonators have the same size parameters. In this embodiment, the dual-path signal sensor includes three resonators with completely identical structural parameters, namely, resonator 1 201, resonator 2 202, and resonator 3 203. The three resonators are distributed in an equilateral triangle, and the resonators are interconnected through three annular coupling beams 1 204, 205, and 3 206 with completely identical structural parameters. The three resonators are respectively fixed by anchor point 1 207 at the center of annular coupling beam 1 204, anchor point 2 208 at the center of annular coupling beam 2 205, and anchor point 3 209 at the center of annular coupling beam 3 206, and a DC bias voltage is applied to the resonator through the anchor point. There are AC drive electrodes 210, 211, and 212 at a certain gap outside the resonator. The AC drive electrodes and the anchor points apply a driving force to the entire weakly coupled resonant system, causing the resonator to perform simple harmonic vibration. At a certain gap outside the three resonators, there are detection electrodes 1 213, 214 and 215, which respectively detect the amplitudes of resonator 1 201, resonator 2 202 and resonator 3 203. At a certain gap outside the resonator 2 202, there is a signal input electrode 1 216, and at a certain gap outside the resonator 2 202, there is a signal input electrode 2 217, which introduces external signals.

[0026] The specific parameters of the dual-channel signal sensor in this embodiment are shown in Table 1:

[0027] Table 1 Dual-channel signal sensor structure parameter table

[0028] name Numeric Equivalent stiffness of the resonator k=144.9N / m The length and width of the resonant beam <![CDATA[l1=2000um,d1=20um]]> Inner and outer diameters of the annular coupling beam <![CDATA[r1=210um,r2=220um]]> The distance between the resonant beam and the intersection of the coupling beam and the anchor point R=10um Length and width of connecting plates <![CDATA[l2=200um,d2=50um]]> Length and width of signal input and detection plates <![CDATA[l3=600um,d3=50um]]> Device thickness D=50um

[0029] The detection steps using the dual-path signal sensor are as follows:

[0030] The first signal is input through the signal input electrode 1 216, generating an electrostatic negative stiffness disturbance on the resonator 1 201, reducing the stiffness of the resonator 1 201 by Δk1. At the same time, the second signal is input through the signal input electrode 2 217, generating an electrostatic negative stiffness disturbance on the resonator 2 202, reducing the stiffness of the resonator 2 202 by Δk2. The stiffness of the three resonators, which originally had exactly the same stiffness, is no longer symmetrical, triggering a modal localization effect. In the initial state, the vibration amplitudes of resonator 1 201, resonator 2 202 and resonator 3 203 are equal, and the amplitude ratio output is 1; after being disturbed by voltage, due to the occurrence of the modal localization phenomenon, the amplitude ratio output of the resonator changes significantly, and Δk1 is detected by the amplitude ratio A3 / A1, and Δk2 is detected by the amplitude ratio A3 / A2.

[0031] Since formulas (1)-(3) are only the derivation of the working principle of the dual-path signal sensor under ideal conditions, it is necessary to evaluate the interference between the two signals of the sensor through finite element simulation analysis. The finite element simulation calculation of the sensor is performed by Comsol Multiphysics (hereinafter referred to as Comsol), and the modal simulation results are shown in Figure 4 As shown, w1 = 18335 Hz. Further input disturbance, when the stiffness disturbance caused by two signals is input from the signal input electrode 1 216 and the signal input electrode 2 217 respectively, the simulation results of the sensor output amplitude ratio changing with the input signal are as follows: Figure 5 As shown, A3 / A1 increases linearly with Δk1, A3 / A2 increases linearly with Δk2, and the repeatability error is less than 0.05%, so the two amplitude ratio outputs can be considered independent of each other. It can be proved by Csomsol finite element simulation calculation that the dual-path signal sensor designed by the present invention can effectively measure two-path signals simultaneously.

[0032] In the description of the present invention, it should be noted that the dual-path signal sensor proposed in the present invention is not only applicable to three-degree-of-freedom modal localization sensors, but four-degree-of-freedom and higher-degree-of-freedom modal localization sensors designed based on the present invention all fall within the protection scope of the claims of the present invention.

[0033] In the description of the present invention, it should be noted that the core technical approach of the dual-path signal sensor proposed by the present invention is the design of three mutually coupled resonators and amplitude detection, which is not limited to the resonator distribution position, coupling beam shape and coupling method. The dual-path signal sensor designed based on the present invention falls within the protection scope of the claims of the present invention.

[0034] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A dual-path signal sensor based on modal localization effect, comprising a resonator 1 (201), a resonator 2 (202), a resonator 3 (203), a coupling beam 1 (204), a coupling beam 2 (205) and a coupling beam 3 (206), wherein the three resonators are respectively connected to fixed anchor points; characterized in that: The three resonators are arranged at the three vertices of an equilateral triangle, the resonator one (201) is connected to the resonator two (202) via the coupling beam one (204), the resonator two (202) is connected to the resonator three (203) via the coupling beam two (205), and the resonator three (203) is connected to the resonator one (201) via the coupling beam three (206), and the three coupling beams one (204), two (205) and three (206) are completely identical, so as to achieve mutual coupling of the three resonators; The structural parameters of the resonator 1 (201), the resonator 2 (202), and the resonator 3 (203) are completely the same; the three resonators are distributed in an equilateral triangle, and the resonators are connected to each other through three coupling beams 1 (204), 2 (205), and 3 (206) with completely the same structural parameters, and the ratio of the coupling stiffness of the coupling beam to the stiffness of the resonator is not higher than 1:100; the three resonators are respectively fixed by anchor point 1 (207), anchor point 2 (208), and anchor point 3 (209), and a DC bias voltage is applied to the resonator through the anchor points; an AC driving electrode is provided at a certain gap outside the resonator; the AC driving electrode and the anchor points provide a DC bias voltage to the entire A driving force is applied to the weak coupling resonant system to make the resonator perform simple harmonic vibration; a detection electrode 1 (213), a detection electrode 2 (214) and a detection electrode 3 (215) are provided at a certain gap outside the three resonators to detect the amplitudes of resonator 1 (201), resonator 2 (202) and resonator 3 (203) respectively; a signal input electrode 1 (216) is provided at a certain gap outside the resonator 1 (201), and a signal input electrode 2 (217) is provided at a certain gap outside the resonator 2 (202), and the signal input electrodes introduce external signals; when the AC driving frequency is kept unchanged, the amplitude ratio A3 / A1 is only related to the input disturbance received by resonator 1 (201). The amplitude ratio is A3 / A2, which is only related to the input disturbance of resonator 2 (202). The relationship is linear; two independent amplitude ratio detections are used to achieve simultaneous detection of dual-path signals.

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