Symmetrical suspension type high-Q-value MEMS resonator and constant temperature control system and method thereof

Abstract

The invention relates to a symmetrical suspension type high-Q-value MEMS resonator and a constant temperature control system and method thereof.The high-Q-value MEMS resonator is of a disc type symmetrical structure, the working mode is a lame mode, the high-Q-value MEMS resonator comprises a sixth clamped anchor point, the left side and the right side of the sixth clamped anchor point are connected with a heat transfer frame through anchoring beams, the interior of the heat transfer frame is connected with a resonator body through a connecting beam, and the left side and the right side of the sixth clamped anchor point are connected with the resonator body. The resonator body is suspended in the heat transfer frame; the upper side and the lower side of the sixth clamped anchor point are connected with the fifth clamped anchor point and the seventh clamped anchor point through micro-resistance beams. The MEMS resonator adopts a suspension type design and adopts a shear mode; the MEMS resonator disclosed by the invention adopts a suspension type design, adopts a shear mode, takes a frequency error as a judgment mark, actively controls the heating efficiency of the Joule heat module, maintains the temperature of the MEMS resonator to be constant, realizes high-precision, low-power-consumption and low-cost temperature compensation, improves the electromechanical coupling coefficient of the resonator, reduces the processing residual stress, and improves the reliability of the MEMS resonator. The thermoelastic loss of the resonator is reduced, and the Q value of the resonator is comprehensively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of clock frequency modulation, and particularly relates to a symmetrical suspension type high-Q value MEMS resonator and a constant temperature control system and method thereof. Background Art

[0002] Clock references are widely used in electronic information, wireless communications and other fields, and determine the performance of electronic information, wireless communications and other systems. Quartz oscillators have occupied the clock market for decades due to their low phase noise and high temperature stability. However, the shortcomings of quartz oscillators such as large size, high power consumption and poor impact resistance seriously restrict their application in miniaturized, small and low-power products. Compared with quartz oscillators, micro-electro-mechanical system (MEMS) oscillators have the advantages of high integration, low power consumption and low cost, showing great development potential.

[0003] MEMS resonator is the core component of MEMS oscillator, and its frequency stability directly determines the upper limit of the stability of MEMS oscillator output frequency. Among MEMS resonators, electrostatic MEMS resonator has the advantages of strong and reliable structure and strong anti-aging ability, but the electromechanical coupling coefficient of electrostatic MEMS resonator is small and the impedance is large; and the electrostatic MEMS resonator of traditional structure has large residual stress during processing. The measures to solve the small electromechanical coupling coefficient and large impedance mainly include increasing the DC drive voltage and reducing the gap between the capacitor plates; increasing the DC drive voltage can effectively increase the electromechanical coupling coefficient of the MEMS resonator and improve the electromechanical conversion efficiency of the resonator, but increasing the DC voltage means additional additional circuits, which increases product costs. Secondly, when the DC voltage exceeds a certain critical value, it will cause the resonator body to attract the excitation detection plate; the electromechanical coupling coefficient of the MEMS resonator can be improved by reducing the gap between the excitation and detection plates and the resonator body, but this method has very high requirements for the processing level, and the final product yield is generally low. In addition, the Q value of existing electrostatic MEMS resonators is generally between 10 4 The order of magnitude restricts the improvement of the frequency stability of the MEMS resonator. At present, in order to improve the Q value of the MEMS resonator, researchers usually adopt methods such as optimizing the anchor point arrangement and setting phononic crystals. These methods are all to reduce the energy loss of the resonator vibration mode by designing the structure to achieve the improvement of the Q value, and the improvement effect is very limited.

[0004] In order to solve the problems of large residual stress and anchor loss in MEMS resonator processing, the existing solutions are mainly achieved by reducing the number of anchor points. For example, a patent application named "MEMS resonator array structure" (CN116318025A) provides a central anchor point design scheme, hoping to reduce the impact of anchor point stress on device performance by reducing the number of anchor points in the resonator support structure; however, reducing the number of anchor points to reduce residual stress and reduce anchor point loss is basic common sense in the field of MEMS resonators; in fact, in the structural design process, it is necessary to comprehensively consider the arrangement and optimization of anchor points in combination with the resonator body structure to improve the overall performance of the MEMS resonator. This patent application does not consider the impact of the arrangement of anchor points on the vibration and energy loss of the resonator body. The support method of the resonator body is unreasonable, which seriously affects the normal vibration of the mode. In addition, the vibration mode Q value of the MEMS resonator is low, which seriously restricts the performance of the resonator. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a symmetrical suspension type high-Q value MEMS resonator and its constant temperature control system and method. The MEMS resonator adopts a suspension design and uses shear mode, takes frequency error as a judgment mark, actively controls the heating efficiency of the Joule heat module, maintains the temperature of the MEMS resonator constant, realizes high-precision, low-power consumption, and low-cost temperature compensation, improves the electromechanical coupling coefficient of the resonator, reduces processing residual stress, reduces the thermoelastic loss of the resonator, and comprehensively improves the Q value of the resonator.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A symmetrical suspension type high Q value MEMS resonator, which is a disk-type symmetrical structure and has a lame mode, comprises a sixth fixed anchor point 2-6, the left and right sides of the sixth fixed anchor point 2-6 are respectively connected by a first anchor beam 2-1, a second anchor beam 2-7 and a first heat transfer frame 1-12 and a second heat transfer frame 3-13; the first heat transfer frame 1-12 is connected to the first resonator body 1-4 through a first connecting beam 1-1, a second connecting beam 1-5, a third connecting beam 1-8, and a fourth connecting beam 1-11; A resonator body 1-4 is suspended in the first heat transfer frame 1-12; the second heat transfer frame 3-13 is connected to the second resonator body 3-10 via the fifth connecting beam 3-3, the sixth connecting beam 3-6, the seventh connecting beam 3-9, and the eighth connecting beam 3-14, and the second resonator body 3-10 is suspended in the second heat transfer frame 3-13; the upper and lower sides of the sixth fixed anchor point 2-6 are respectively connected through the first micro-resistance beam 2-4, the second micro-resistance beam 2-10 and the fifth fixed anchor point 2-3 and the seventh fixed anchor point 2-9.

[0008] The first connecting beam 1-1, the second connecting beam 1-5, the third connecting beam 1-8, and the fourth connecting beam 1-11 are respectively provided with a first fixed support anchor point 1-3, a second fixed support anchor point 1-6, a third fixed support anchor point 1-9, and a fourth fixed support anchor point 1-14; the first fixed support anchor point 1-3, the second fixed support anchor point 1-6, the third fixed support anchor point 1-9, and the fourth fixed support anchor point 1-14 are respectively provided with a first metal electrode layer 1-2, a second metal electrode layer 1-7, a third metal electrode layer 1-10, and a fourth metal electrode layer 1-13; the fifth connecting beam 3-3, the sixth connecting beam 3-6, the seventh connecting beam 3-9, and the eighth connecting beam 3-10 are respectively provided with a first metal electrode layer 1-2, a second metal electrode layer 1-7, a third metal electrode layer 1-10, and a fourth metal electrode layer 1-13; -14 are respectively provided with an eighth support anchor point 3-1, a ninth support anchor point 3-4, a tenth support anchor point 3-7 and an eleventh support anchor point 3-12; the eighth support anchor point 3-1, the ninth support anchor point 3-4, the tenth support anchor point 3-7 and the eleventh support anchor point 3-12 are respectively provided with an eighth metal electrode layer 3-2, a ninth metal electrode layer 3-5, a tenth metal electrode layer 3-8 and an eleventh metal electrode layer 3-11; the fifth support anchor point 2-3, the sixth support anchor point 2-6 and the seventh support anchor point 2-9 are respectively provided with a fifth metal electrode layer 2-2, a sixth metal electrode layer 2-5 and a seventh metal electrode layer 2-8.

[0009] The first micro-resistance beam 2-4, the second micro-resistance beam 2-10, the fifth support anchor point 2-3, the sixth support anchor point 2-6 and the seventh support anchor point 2-9 constitute the Joule heating module of the MEMS resonator; the first metal electrode layer 1-2, the first support anchor point 1-3, the third support anchor point 1-9, the third metal electrode layer 1-10, the eighth support anchor point 3-1, the eighth metal electrode layer 3-2, the tenth support anchor point 3-7, and the tenth metal electrode layer 3-8 constitute an excitation module; the second support anchor point 1-6, the second metal electrode layer 1-7, the fourth metal electrode layer 1-13, the fourth support anchor point 1-14, the ninth support anchor point 3-4, the ninth metal electrode layer 3-5, the eleventh metal electrode layer 3-11, and the eleventh support anchor point 3-12 constitute a detection module.

[0010] The first resonator body 1-4 and the second resonator body 3-10 are both square disc-shaped; the first support anchor point 1-3, the first metal electrode layer 1-2, the second support anchor point 1-6, the second metal electrode layer 1-7, the third support anchor point 1-9, the third metal electrode layer 1-10, the fourth support anchor point 1-14, the fourth metal electrode layer 1-13 and the first resonator body 1-4 form a spacing of 3 μm; the eighth support anchor point 3-1, the eighth metal electrode layer 3-2, the ninth support anchor point 3-4, the ninth metal electrode layer 3-5, the tenth support anchor point 3-7, the tenth metal electrode layer 3-8, the eleventh support anchor point 3-12, the eleventh metal electrode layer 3-11 and the second resonator body 3-10 form a spacing of 3 μm; a parallel plate capacitor is formed, and the resonator is excited and detected by the parallel plate capacitor.

[0011] A constant temperature control system for a symmetrical suspension type high-Q value MEMS resonator, comprising:

[0012] Two closed-loop oscillation circuits 4-1: one closed-loop oscillation circuit 4-1 input is connected to the first metal electrode layer 1-2, the second metal electrode layer 1-7, the third metal electrode layer 1-10, and the fourth metal electrode layer 1-13 outside the first resonator body 1-4; the other closed-loop oscillation circuit 4-1 input is connected to the eighth metal electrode layer 3-2, the ninth metal electrode layer 3-5, the tenth metal electrode layer 3-8, and the eleventh metal electrode layer 3-11, and the two closed-loop oscillation circuits 4-1 realize the closed-loop oscillation of the MEMS resonator;

[0013] Two frequency reading modules 4-2: The inputs of the two frequency reading modules 4-2 are respectively connected to the outputs of the two closed-loop oscillation circuits 4-1, and the two frequency reading modules 4-2 are used to realize reading the frequency signal of the resonator;

[0014] Two control modules 4-3: The outputs of the two frequency reading modules 4-2 are respectively connected to the two control modules 4-3, and the two control modules 4-3 are used to process the frequency signal and generate a control signal for controlling the temperature;

[0015] Two AD / DA modules 4-4: The outputs of the two control modules 4-3 are respectively connected to the inputs of the two AD / DA modules 4-4, and the outputs of the two AD / DA modules 4-4 are respectively connected to the fifth metal electrode layer 2-2 and the seventh metal electrode layer 2-8. The two AD / DA modules 4-4 are used to perform analog / digital conversion and amplify the control signals.

[0016] The closed-loop oscillation circuit 4-1 includes an amplitude amplifier for amplifying the amplitude of the resonator response; a phase regulator for adjusting the loop phase information; a signal controller for amplifying the detection signal; and a MEMS resonator for generating a frequency signal in the closed-loop oscillation circuit.

[0017] The frequency reading module 4 - 2 includes a frequency reading part for reading the frequency change of the MEMS resonator in real time; and an analog / digital conversion part for converting the detection signal into a digital signal.

[0018] The control module 4-3 includes an error calculation part for calculating the error between the detection signal and the set frequency; and a control algorithm part for generating a control signal for controlling the thermal efficiency of the Joule heat module.

[0019] The closed-loop oscillation circuit 4-1 adopts a Barkhausen oscillation circuit, a phase-locked loop (PLL) oscillation circuit or a Pierce oscillation circuit.

[0020] The control algorithm in the control module 4-3 adopts PID algorithm, adaptive control algorithm or genetic algorithm.

[0021] The control method of the constant temperature control system based on the symmetrical suspension type high-Q value MEMS resonator comprises the following steps:

[0022] Step 1, the MEMS resonator forms self-excited oscillation through two closed-loop oscillation circuits 4-1;

[0023] Step 2, two frequency reading modules 4-2 read the frequency change of the MEMS resonator in real time, and transmit it to two control modules 4-3 after analog-to-digital conversion;

[0024] Step 3, the two control modules 4-3 calculate the frequency change, calculate the control signal applied to the Joule heat module through the control algorithm, and transmit it to the two AD / DA modules 4-4;

[0025] Step 4, two AD / DA modules 4-4 perform analog-to-digital conversion on the control signal and amplify it, and finally apply it to both ends of the Joule heating module, and the Joule heating module generates resistance heat to maintain a constant temperature of the resonator;

[0026] Step 5, return to step 2, repeatedly read the frequency of the MEMS resonator, control the temperature of the MEMS resonator, and achieve stable output of the resonator frequency.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention discloses a symmetrical suspension type high-Q value MEMS resonator and a constant temperature control system and method thereof. The MEMS resonator improves the electromechanical coupling coefficient of the MEMS resonator through a symmetrical structural design; through a suspension type design, the resonator is suspended on a heat transfer frame so that heat is evenly transferred to the resonator; the MEMS resonator is anchored through a fifth fixed anchor point 2-3, a sixth fixed anchor point 2-6, and a seventh fixed anchor point 2-9 to reduce processing residual stress; at the same time, the MEMS resonator adopts a shear mode, and the stress gradient of the mode is small during vibration, thereby reducing the thermoelastic loss of the resonator; the comprehensive suspension structure reduces the coupling between the resonator body and the substrate, reduces the energy dissipated by the resonator through the anchor point during vibration, and improves the Q value of the MEMS resonator; in addition, the frequency error is used as a judgment mark to actively control the heating efficiency of the Joule heat module, maintain the constant temperature of the MEMS resonator, and realize high-precision, low-power consumption, and low-cost temperature compensation; finally, through the above four designs, the stability of the output frequency of the MEMS resonator is finally improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural diagram of a symmetrically suspended high-Q MEMS resonator according to an embodiment of the present invention.

[0030] Figure 2 It is a schematic diagram of the temperature adjustment capability of an embodiment of the present invention when the external environment is -40°C.

[0031] Figure 3 In the figure, (a) is a schematic diagram of the simulation of the thermoelastic loss of the shear mode of an embodiment of the present invention; (b) is a schematic diagram of the simulation comparison of the thermoelastic loss of the shear mode of an embodiment of the present invention and the thermoelastic loss of the traditional body mode.

[0032] Figure 4 The figure is a structural principle diagram of a constant temperature control system according to an embodiment of the present invention.

[0033] Figure 5 Flowchart of a control method of a constant temperature control system according to an embodiment of the present invention.

[0034] In the figure: 1-1 is the first connecting beam; 1-2 is the first metal electrode layer; 1-3 is the first fixed anchor point; 1-4 is the first resonator body; 1-5 is the second connecting beam; 1-6 is the second fixed anchor point; 1-7 is the second metal electrode layer; 1-8 is the third connecting beam; 1-9 is the third fixed anchor point; 1-10 is the third metal electrode layer; 1-11 is the fourth connecting beam; 1-12 is the first heat transfer frame; 1-13 is the fourth metal electrode layer; 1-14 is the fourth fixed anchor point; 2-1 is the first anchoring beam; 2-2 is the fifth metal electrode layer; 2-3 is the fifth fixed anchor point; 2-4 is the first micro-resistance beam; 2-5 is the sixth metal electrode layer; 2-6 is the sixth fixed anchor point; 2-7 is the second anchoring beam; 2-8 is the seventh metal electrode layer; 2-9 is the seventh fixed anchor point; 2-10 is the second micro-resistance beam; 3-1 is the eighth fixed anchor point; 3-2 is the eighth metal electrode layer; 3-3 is the fifth connecting beam; 3-4 is the ninth fixed anchor point; 3-5 is the ninth metal electrode layer; 3-6 is the sixth connecting beam; 3-7 is the tenth fixed anchor point; 3-8 is the tenth metal electrode layer; 3-9 is the seventh connecting beam; 3-10 is the second resonator body; 3-11 is the eleventh metal electrode layer; 3-12 is the eleventh fixed anchor point; 3-13 is the second heat transfer frame; 3-14 is the eighth connecting beam; 4-1 is a closed-loop oscillation circuit; 4-2 is a frequency reading module; 4-3 is a signal control module; 4-4 is an AD / DA module. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is described clearly and completely below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0036] A symmetrical suspension type high Q value MEMS resonator and a constant temperature control system and method, wherein the resonant frequency of the resonator has a great relationship with the temperature change. The essence is that the change of the ambient temperature will cause the change of the Young's modulus of the resonator, thereby causing the resonant frequency of the resonator to change. Taking a disk resonator as an example, the specific relationship is shown in formula (1);

[0037]

[0038] In formula (1), λ i is the modal constant, r is the radius of the circle, ρ is the density, σ is the Poisson's ratio, ΔT is the temperature change, and TCE is the change of Young's variable with temperature;

[0039] It can be seen intuitively from formula (1) that as the temperature variation range of the resonator increases, the temperature difference ΔT will also increase, which will eventually lead to an increase in the frequency variation of the resonator. The present invention will provide a symmetrical suspended high-Q value MEMS resonator and a constant temperature control system and method thereof to achieve accurate and uniform control of temperature, so that the MEMS resonator can output a stable frequency signal.

[0040] like Figure 1 As shown, a symmetrical suspension type high Q value MEMS resonator is a disk-type symmetrical structure, and the working mode is a lame mode; specifically, it includes a sixth fixed anchor point 2-6, the left side of the sixth fixed anchor point 2-6 is connected to the first heat transfer frame 1-12 via the first anchoring beam 2-1, the inside of the first heat transfer frame 1-12 is connected to the first resonator body 1-4 via the first connecting beam 1-1, the second connecting beam 1-5, the third connecting beam 1-8, and the fourth connecting beam 1-11, A first fixed support anchor point 1-3, a second fixed support anchor point 1-6, a third fixed support anchor point 1-9, and a fourth fixed support anchor point 1-14 are arranged between the connecting beams 1-11, and a first metal electrode layer 1-2, a second metal electrode layer 1-7, a third metal electrode layer 1-10, and a fourth metal electrode layer 1-13 are arranged on the first fixed support anchor point 1-3, the second fixed support anchor point 1-6, the third fixed support anchor point 1-9, and the fourth fixed support anchor point 1-14; the right side of the sixth fixed support anchor point 2-6 is connected to the second heat transfer frame 3-13 via the second anchoring beam 2-7, and the second heat transfer frame 3- 13 is connected to the second resonator body 3-10 through the fifth connecting beam 3-3, the sixth connecting beam 3-6, the seventh connecting beam 3-9, the eighth connecting beam 3-14, and the eighth connecting beam 3-12. The eighth fixing anchor point 3-1, the ninth fixing anchor point 3-4, the tenth fixing anchor point 3-7, and the eleventh fixing anchor point 3-12 are arranged between the fifth connecting beam 3-3, the sixth connecting beam 3-6, the seventh connecting beam 3-9, and the eighth connecting beam 3-14. The eighth metal electrode layer 3-2, the ninth metal electrode layer 3-5, the tenth metal electrode layer 3-8, and the eleventh metal electrode layer 3-11; the upper side of the sixth fixed anchor point 2-6 is connected to the fifth fixed anchor point 2-3 via the first micro-resistance beam 2-4, and the lower side of the sixth fixed anchor point 2-6 is connected to the seventh fixed anchor point 2-9 via the second micro-resistance beam 2-10, and the fifth metal electrode layer 2-2, the sixth metal electrode layer 2-5, and the seventh metal electrode layer 2-8 are provided on the fifth fixed anchor point 2-3, the sixth fixed anchor point 2-6, and the seventh fixed anchor point 2-9;

[0041] The MEMS resonator adopts a suspension design to reduce the coupling between the resonator body and the substrate, and reduce the energy dissipated by the resonator through the anchor point during vibration; the MEMS resonator adopts a shear mode to reduce the thermoelastic loss of the resonator, improve the Q value of the resonator, and improve the stability of the MEMS resonator output frequency.

[0042] The first micro-resistance beam 2-4, the second micro-resistance beam 2-10, the fifth fixed support anchor point 2-3, the sixth fixed support anchor point 2-6 and the seventh fixed support anchor point 2-9 constitute a Joule heat module of the MEMS resonator. According to the frequency change of the resonator body, the resonator body generates a current for compensating for the temperature change of the resonator. The Joule heat module generates resistance heat under the action of the control current. The resistance heat is evenly transferred to the resonator body through the anchor beam and the heat transfer frame to maintain the constant temperature of the MEMS resonator. The first metal electrode layer 1-2, the first fixed support anchor point 1-3, the third fixed support anchor point 2-6 and the seventh fixed support anchor point 2-9 The support anchor point 1-9, the third metal electrode layer 1-10, the eighth support anchor point 3-1, the eighth metal electrode layer 3-2, the tenth support anchor point 3-7, and the tenth metal electrode layer 3-8 constitute an excitation module for driving the resonator; the second support anchor point 1-6, the second metal electrode layer 1-7, the fourth metal electrode layer 1-13, the fourth support anchor point 1-14, the ninth support anchor point 3-4, the ninth metal electrode layer 3-5, the eleventh metal electrode layer 3-11, and the eleventh support anchor point 3-12 constitute a detection module for detecting the resonant motion of the resonator.

[0043] The first resonator body 1-4 and the second resonator body 3-10 are square disc-shaped; the first support anchor point 1-3, the first metal electrode layer 1-2, the second support anchor point 1-6, the second metal electrode layer 1-7, the third support anchor point 1-9, the third metal electrode layer 1-10, the fourth support anchor point 1-14, the fourth metal electrode layer 1-13 and the first resonator body 1-4 form a spacing of 3 μm; the eighth support anchor point 3-1, the eighth metal electrode layer 3-2, the ninth support anchor point 3-4, the ninth metal electrode layer 3-5, the tenth support anchor point 3-7, the tenth metal electrode layer 3-8, the eleventh support anchor point 3-12, the eleventh metal electrode layer 3-11 and the second resonator body 3-10 form a spacing of 3 μm; a parallel plate capacitor is formed, and the resonator can be excited and detected by the parallel plate capacitor.

[0044] like Figure 2 As shown, the MEMS resonator of this embodiment is modeled using the Joule heat and thermal expansion module in COMSOL Multiphysics. The Joule heat effect of the MEMS resonator is simulated when the working environment of the MEMS resonator is the most extreme, that is, when the external environment is -40°C. Figure 2It can be seen that when the external environment is -40°C, the MEMS resonator of this embodiment can achieve temperature adjustment from -40°C to 85°C, and the resonator is heated evenly.

[0045] like Figure 3 As shown in (a), a symmetrical suspension type high-Q value MEMS resonator of this embodiment adopts a second-order Lame mode, and the resonator body is square;

[0046] like Figure 3 As shown in (b), the thermoelastic quality factor Q of the bulk mode and shear mode of the MEMS resonator under isothermal boundary conditions is calculated using COMSOL Multiphysics. TED ; In the simulation results, the temperature distribution of the shear mode during vibration is more uniform, so it has a high 8 Q TED ; However, due to the larger stress gradient, the thermoelastic loss of the bulk mode is larger, and its Q TED is 3.9810×10 7 .

[0047] For a given material, the upper limit of its quality factor Q is determined by the Akhiezer damping of the material, and the upper limit value of this quality factor can be given by the following expression:

[0048]

[0049] In formula (2), f is the resonant frequency, ρ is the density, c is the speed of sound, and c D is the Debye speed, γ eff is the effective Grüneisen parameter, κ is the thermal conductivity and T is the temperature.

[0050] According to formula (2), the upper limit of the Q value of the MEMS resonator is theoretically 4.283×10 6 In this embodiment, the suspension structure is adopted to reduce the anchor loss and the shear mode is adopted to reduce the thermoelastic loss. The actual Q value of the MEMS resonator can reach 2.751×10 6 , which is very close to the quantum limit of the resonator's quality factor.

[0051] like Figure 4 As shown, a constant temperature control system of a symmetrical suspension high-Q value MEMS resonator includes:

[0052] Two closed-loop oscillation circuits 4-1: one closed-loop oscillation circuit 4-1 input is connected to the first metal electrode layer 1-2, the second metal electrode layer 1-7, the third metal electrode layer 1-10, and the fourth metal electrode layer 1-13 outside the first resonator body 1-4; the other closed-loop oscillation circuit 4-1 input is connected to the eighth metal electrode layer 3-2, the ninth metal electrode layer 3-5, the tenth metal electrode layer 3-8, and the eleventh metal electrode layer 3-11, and the two closed-loop oscillation circuits 4-1 realize the closed-loop oscillation of the MEMS resonator;

[0053] Two frequency reading modules 4-2: The inputs of the two frequency reading modules 4-2 are respectively connected to the outputs of the two closed-loop oscillation circuits 4-1, and the two frequency reading modules 4-2 are used to realize reading the frequency signal of the resonator;

[0054] Two control modules 4-3: The outputs of the two frequency reading modules 4-2 are respectively connected to the two control modules 4-3, and the two control modules 4-3 are used to process the frequency signal and generate a control signal for controlling the temperature;

[0055] Two AD / DA modules 4-4: The outputs of the two control modules 4-3 are respectively connected to the inputs of the two AD / DA modules 4-4, and the outputs of the two AD / DA modules 4-4 are respectively connected to the fifth metal electrode layer 2-2 and the seventh metal electrode layer 2-8. The two AD / DA modules 4-4 are used to perform analog / digital conversion and amplify the control signals.

[0056] The closed-loop oscillation circuit 4-1 includes an amplitude amplifier for amplifying the amplitude of the resonator response; a phase regulator for adjusting the loop phase information; a signal controller for amplifying the detection signal and filtering out stray signals therein; and a MEMS resonator for generating a frequency signal in the closed-loop oscillation circuit.

[0057] The frequency reading module 4 - 2 includes a frequency reading part for reading the frequency change of the MEMS resonator in real time; and an analog / digital conversion part for converting the detection signal into a digital signal.

[0058] The control module 4-3 includes an error calculation part for calculating the error between the detection signal and the set frequency; and a control algorithm part for generating a control signal for controlling the thermal efficiency of the Joule heat module.

[0059] The closed-loop oscillation circuit 4-1 adopts a Barkhausen oscillation circuit, a phase-locked loop (PLL) oscillation circuit or a Pierce oscillation circuit.

[0060] The control algorithm in the control module 4-3 adopts PID algorithm, adaptive control algorithm or genetic algorithm.

[0061] like Figure 5As shown, a control method for a constant temperature control system based on the symmetrical suspension type high-Q value MEMS resonator comprises the following steps:

[0062] Step 1, the MEMS resonator forms self-excited oscillation through two closed-loop oscillation circuits 4-1;

[0063] Step 2, two frequency reading modules 4-2 read the frequency change of the MEMS resonator in real time, and transmit it to two control modules 4-3 after analog-to-digital conversion;

[0064] Step 3, the two control modules 4-3 calculate the frequency change, calculate the control signal applied to the Joule heat module through the control algorithm, and transmit it to the two AD / DA modules 4-4;

[0065] Step 4, two AD / DA modules 4-4 perform analog-to-digital conversion on the control signal and amplify it, and finally apply it to both ends of the Joule heating module, and the Joule heating module generates resistance heat to maintain a constant temperature of the resonator;

[0066] Step 5, return to step 2, repeatedly read the frequency of the MEMS resonator, control the temperature of the MEMS resonator, and achieve stable output of the resonator frequency.

[0067] The principle of the above control method is as follows:

[0068] The excitation signal makes the resonator vibrate through the excitation anchor points (the first fixed anchor point 1-3, the third fixed anchor point 1-9, the eighth fixed anchor point 3-1, and the tenth fixed anchor point 3-7) of the excitation module. After the electrostatic detection of the parallel plate capacitor, the vibration signal of the resonator enters two closed-loop oscillation circuits 4-1 containing an amplitude amplifier, a phase regulator, and a signal controller;

[0069] The signals generated by the amplitude amplifiers in the two closed-loop oscillation circuits 4-1 will be divided into two paths, one path will be fed back to the excitation electrode to form the self-excited oscillation of the MEMS resonator, and the other path will be used as a detection signal and sent to the frequency reading module 4-2 for detection or output;

[0070] The two frequency reading modules 4-2 are responsible for collecting and outputting the frequency signal of the MEMS resonator, and converting the frequency signal into a digital signal and transmitting it to the two control modules 4-3. The two control modules 4-3 process the transmitted digital signal, compare the digital signal with the set signal through relevant algorithms such as PID, fuzzy PID, etc., calculate the frequency signal deviation, and judge whether the deviation is within the allowable range. If it is within the allowable range, the frequency is output after it is stabilized. If it is not within the allowable range, the control signal applied to both ends of the Joule heat module is calculated according to the deviation;

[0071] The control signals output by the two control modules 4-3 are transmitted to the two AD / DA modules 4-4, which convert the digital signals into analog signals and amplify them to a certain extent, and finally apply them to both ends of the Joule heating module. The Joule heating module generates resistive heat through electric current, and the resistive heat is evenly transferred to the resonator through the anchoring beam and the heat transfer frame, thereby realizing temperature control of the MEMS resonator.

[0072] 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 symmetrical suspension high-Q MEMS resonator, characterized in that: The invention is a disc-type symmetrical structure, the working mode is a lame mode, and comprises a sixth fixed support anchor point (2-6), the left and right sides of the sixth fixed support anchor point (2-6) are respectively connected through a first anchor beam (2-1), a second anchor beam (2-7) and a first heat transfer frame (1-12), and a second heat transfer frame (3-13); the first heat transfer frame (1-12) is connected to a first resonator body (1-4) through a first connecting beam (1-1), a second connecting beam (1-5), a third connecting beam (1-8), and a fourth connecting beam (1-11), and the first resonator body (1-4) is suspended The second heat transfer frame (3-13) is connected to the second resonator body (3-10) via a fifth connecting beam (3-3), a sixth connecting beam (3-6), a seventh connecting beam (3-9) and an eighth connecting beam (3-14), and the second resonator body (3-10) is suspended in the second heat transfer frame (3-13); the upper and lower sides of the sixth fixed support anchor point (2-6) are respectively connected via the first micro-resistance beam (2-4), the second micro-resistance beam (2-10) and the fifth fixed support anchor point (2-3) and the seventh fixed support anchor point (2-9).

2. The symmetrically suspended high-Q MEMS resonator according to claim 1, characterized in that: A first fixed support anchor point (1-3), a second fixed support anchor point (1-6), a third fixed support anchor point (1-9), and a fourth fixed support anchor point (1-14) are respectively arranged between the first connecting beam (1-1), the second connecting beam (1-5), the third connecting beam (1-8), and the fourth connecting beam (1-11); a first metal electrode layer (1-2), a second metal electrode layer (1-7), a third metal electrode layer (1-10), and a fourth metal electrode layer (1-13) are respectively arranged on the first fixing anchor point (1-3), the second fixing anchor point (1-6), the third fixing anchor point (1-9), and the fourth fixing anchor point (1-14); and a fifth connecting beam (3-3), a sixth connecting beam (3-6), a seventh connecting beam (3-9), an eighth connecting beam ( An eighth support anchor point (3-1), a ninth support anchor point (3-4), a tenth support anchor point (3-7), and an eleventh support anchor point (3-12) are respectively arranged between the first and second support anchor points (3-14); an eighth metal electrode layer (3-2), a ninth metal electrode layer (3-5), a tenth metal electrode layer (3-8), and an eleventh metal electrode layer (3-11) are respectively arranged on the eighth support anchor point (3-1), the ninth support anchor point (3-4), the tenth support anchor point (3-7), and the eleventh support anchor point (3-12); and a fifth metal electrode layer (2-2), a sixth metal electrode layer (2-5), and a seventh metal electrode layer (2-8) are respectively arranged on the fifth support anchor point (2-3), the sixth support anchor point (2-6), and the seventh support anchor point (2-9).

3. The symmetrically suspended high-Q MEMS resonator according to claim 2, characterized in that: The first micro-resistance beam (2-4), the second micro-resistance beam (2-10), the fifth fixed support anchor point (2-3), the sixth fixed support anchor point (2-6) and the seventh fixed support anchor point (2-9) constitute a Joule heat module of the MEMS resonator; the first metal electrode layer (1-2), the first fixed support anchor point (1-3), the third fixed support anchor point (1-9), the third metal electrode layer (1-10), the eighth fixed support anchor point (3-1), the eighth metal electrode layer (3-2), the tenth fixed support anchor point (3-7) and the tenth metal electrode layer (3-8) constitute an excitation module; the second fixed support anchor point (1-6), the second metal electrode layer (1-7), the fourth metal electrode layer (1-13), the fourth fixed support anchor point (1-14), the ninth fixed support anchor point (3-4), the ninth metal electrode layer (3-5), the eleventh metal electrode layer (3-11) and the eleventh fixed support anchor point (3-12) constitute a detection module.

4. The symmetrically suspended high-Q MEMS resonator according to claim 2, characterized in that: The first resonator body (1-4) and the second resonator body (3-10) are square disk-shaped; the first support anchor point (1-3), the first metal electrode layer (1-2), the second support anchor point (1-6), the second metal electrode layer (1-7), the third support anchor point (1-9), the third metal electrode layer (1-10), the fourth support anchor point (1-14), the fourth metal electrode layer (1-13) and the first resonator body (1-4) form a spacing of 3 μm; the eighth support anchor point (3-1), the eighth metal electrode layer (3-2), the ninth support anchor point (3-4), the ninth metal electrode layer (3-5), the tenth support anchor point (3-7), the tenth metal electrode layer (3-8), the eleventh support anchor point (3-12), the eleventh metal electrode layer (3-11) and the second resonator body (3-10) form a spacing of 3 μm; a parallel plate capacitor is formed, and the resonator is excited and detected by the parallel plate capacitor.

5. A constant temperature control system for a symmetrically suspended high-Q MEMS resonator as described in claims 1-4, characterized in that: include: Two closed-loop oscillation circuits (4-1): one closed-loop oscillation circuit (4-1) input is connected to the first metal electrode layer (1-2), the second metal electrode layer (1-7), the third metal electrode layer (1-10), and the fourth metal electrode layer (1-13) outside the first resonator body (1-4); the other closed-loop oscillation circuit (4-1) input is connected to the eighth metal electrode layer (3-2), the ninth metal electrode layer (3-5), the tenth metal electrode layer (3-8), and the eleventh metal electrode layer (3-11), and the two closed-loop oscillation circuits (4-1) realize the closed-loop oscillation of the MEMS resonator; Two frequency reading modules (4-2): inputs of the two frequency reading modules (4-2) are respectively connected to outputs of the two closed-loop oscillation circuits (4-1), and the two frequency reading modules (4-2) are used to read the frequency signal of the resonator; Two control modules (4-3): the outputs of the two frequency reading modules (4-2) are respectively connected to the two control modules (4-3), and the two control modules (4-3) are used to process the frequency signal and generate a control signal for controlling the temperature; Two AD / DA modules (4-4): the outputs of the two control modules (4-3) are respectively connected to the inputs of the two AD / DA modules (4-4); the outputs of the two AD / DA modules (4-4) are respectively connected to the fifth metal electrode layer (2-2) and the seventh metal electrode layer (2-8); the two AD / DA modules (4-4) are used to perform analog / digital conversion on the control signals and to amplify them.

6. The constant temperature control system of a symmetrically suspended high-Q MEMS resonator according to claim 5, characterized in that: The closed-loop oscillation circuit (4-1) comprises an amplitude amplifier for amplifying the amplitude of the resonator response; a phase regulator for adjusting the loop phase information; and a signal controller for amplifying the detection signal. MEMS resonator is used to generate a frequency signal in a closed-loop oscillation circuit.

7. The constant temperature control system of a symmetrically suspended high-Q MEMS resonator according to claim 5, characterized in that: The frequency reading module (4-2) comprises a frequency reading part for reading the frequency change of the MEMS resonator in real time; and an analog / digital conversion part for converting the detection signal into a digital signal.

8. The constant temperature control system of a symmetrically suspended high-Q MEMS resonator according to claim 5, characterized in that: The control module (4-3) comprises an error calculation part for calculating the error between the detection signal and the set frequency; and a control algorithm part for generating a control signal for controlling the thermal efficiency of the Joule heat module.

9. The constant temperature control system of a symmetrically suspended high-Q MEMS resonator according to claim 5, characterized in that: The closed-loop oscillation circuit (4-1) adopts a Barkhausen oscillation circuit, a phase-locked loop (PLL) oscillation circuit or a Pierce oscillation circuit; the control algorithm in the control module (4-3) adopts a PID algorithm, an adaptive control algorithm or a genetic algorithm.

10. A control method for a constant temperature control system of a symmetrically suspended high-Q MEMS resonator according to claims 6-9, characterized in that: The following steps are involved: Step 1, the MEMS resonator forms self-excited oscillation through two closed-loop oscillation circuits (4-1); Step 2, two frequency reading modules (4-2) read the frequency change of the MEMS resonator in real time, and transmit it to two control modules (4-3) after analog-to-digital conversion; Step 3, the two control modules (4-3) calculate the frequency change, calculate the control signal applied to the Joule heat module through the control algorithm, and transmit it to the two AD / DA modules (4-4); Step 4, two AD / DA modules (4-4) perform analog-to-digital conversion on the control signal and amplify it, and finally apply it to both ends of the Joule heating module, and the Joule heating module generates resistance heat to maintain the temperature of the resonator constant; Step 5, return to step 2, repeatedly read the frequency of the MEMS resonator, control the temperature of the MEMS resonator, and achieve stable output of the resonator frequency.

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