A symmetric suspension type high Q value MEMS resonator and a constant temperature control system and method thereof

Abstract

A kind of symmetric suspension type high Q value MEMS resonator and its constant temperature control system and method, high Q value MEMS resonator is disc type symmetric structure, working mode is lame mode, including the sixth fixed support anchor point, the left and right sides of the sixth fixed support anchor point are connected by anchor beam and a heat transfer frame, the resonator body is connected by connecting beam in heat transfer frame, and the resonator body is suspended in heat transfer frame;The upper and lower sides of the sixth fixed support anchor point are connected by micro resistance beam and the fifth fixed support anchor point, the seventh fixed support anchor point;MEMS resonator adopts suspension type design, and adopts shear mode;The MEMS resonator of the present application adopts suspension type design, and adopts shear mode, with frequency error as judging mark, actively control the heating efficiency of joule heat module, maintain the temperature of MEMS resonator constant, realize high-precision, low-power, low-cost temperature compensation, improve the electromechanical coupling coefficient of resonator, reduce the processing residual stress, reduce the thermal elastic loss of resonator, and comprehensively improve the Q value of resonator.

Description

TECHNICAL FIELD

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

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

[0003] The MEMS resonator is the core element of the MEMS oscillator, and the frequency stability of the MEMS resonator directly determines the upper limit of the frequency stability of the MEMS oscillator. The electrostatic MEMS resonator in the MEMS resonator has the advantages of solid and reliable structure and strong anti-aging ability, but the electrostatic MEMS resonator has small electromechanical coupling coefficient and large impedance. And the residual stress of the traditional structure of the electrostatic MEMS resonator is large. The measures to solve the small electromechanical coupling coefficient and large impedance mainly include increasing the direct current driving voltage and reducing the gap between the capacitor plates. Increasing the direct current driving voltage can effectively increase the electromechanical coupling coefficient of the MEMS resonator and improve the electromechanical conversion efficiency of the resonator, but increasing the direct current voltage means additional circuit, which increases the product cost, and secondly, when the direct current voltage exceeds a certain critical value, it will cause the resonator body and the excitation detection plate to be attracted. By reducing the gap between the excitation and detection plates and the resonator body, the electromechanical coupling coefficient of the MEMS resonator can be improved, but this method has very high requirements for the processing level, and the final processing product yield is generally low. In addition, the Q value of the existing electrostatic MEMS resonator is generally in the order of 10 4 The number, which restricts the improvement of the frequency stability of the MEMS resonator. At present, researchers usually use methods such as optimizing the anchor point arrangement and setting the phononic crystal to improve the Q value of the MEMS resonator. These methods all achieve the improvement of the Q value by designing the structure to reduce the energy loss of the resonator vibration mode, and the improvement effect is very limited.

[0004] In view of the problem of large residual stress and anchor loss in MEMS resonator processing, the existing scheme mainly reduces the number of anchor points to achieve it, for example, the patent application named "MEMS resonator array structure" (CN116318025A) provides a central anchor point design scheme, hoping to reduce the influence of anchor 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 loss is a basic common sense in the field of MEME resonator; in fact, the arrangement and optimization of the anchor points need to be considered comprehensively in combination with the resonator body structure during the structural design process, so as to improve the overall performance of the MEMS resonator, the patent application does not consider the influence of the arrangement of the anchor points on the vibration and energy loss of the resonator body, the support mode of the resonator body is unreasonable, which seriously affects the normal vibration of the mode, and the vibration mode Q value of the MEMS resonator is low, which seriously restricts the performance of the resonator. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application 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 type design and uses a 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 and low-cost temperature compensation, improves the electromechanical coupling coefficient of the resonator, reduces the processing residual stress, reduces the thermal elastic loss of the resonator, and comprehensively improves the Q value of the resonator.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] A symmetrical suspension type high Q value MEMS resonator is a disc type symmetrical structure, the working mode is lame mode, comprising a sixth fixed support anchor point 2-6, the left and right sides of the sixth fixed support anchor point 2-6 are connected through a first anchor beam 2-1, a second anchor beam 2-7 and a first heat transfer frame 1-12, a second heat transfer frame 3-13; 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 are connected in the first heat transfer frame 1-12 to connect a first resonator body 1-4, and the first resonator body 1-4 is suspended in the first heat transfer frame 1-12; 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 are connected in the second heat transfer frame 3-13 to connect a second resonator body 3-10, 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 connected through a first micro-resistance beam 2-4, a second micro-resistance beam 2-10, a fifth fixed support anchor point 2-3 and a seventh fixed support 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, and 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 3-14 are respectively provided with an eighth fixed support anchor point 3-1, a ninth fixed support anchor point 3-4, a tenth fixed support anchor point 3-7, and an eleventh fixed support anchor point 3-12, and the eighth fixed support anchor point 3-1, the ninth fixed support anchor point 3-4, the tenth fixed support anchor point 3-7, and the eleventh fixed 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 fixed support anchor point 2-3, the sixth fixed support anchor point 2-6, and the seventh fixed 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 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; and 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.

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

[0011] A constant temperature control system of a symmetric suspension type high-Q MEMS resonator, comprising:

[0012] Two closed-loop oscillation circuits 4-1: one closed-loop oscillation circuit 4-1 is connected with 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; and the other closed-loop oscillation circuit 4-1 is connected with 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 closed-loop oscillation of the MEMS resonator.

[0013] Two frequency reading modules 4-2: the two frequency reading modules 4-2 are respectively connected with the outputs of the two closed-loop oscillation circuits 4-1, and the two frequency reading modules 4-2 are used to read the frequency signals of the resonator.

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

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

[0016] The closed-loop oscillation circuit 4-1 comprises an amplitude amplifier for amplifying the amplitude of the resonator response, a phase adjuster for adjusting the phase information of the loop, 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 comprises a frequency reading part for reading the frequency change of the MEMS resonator in real time, and an analog-to-digital conversion part for converting the detection signal into a digital signal.

[0018] The control module 4-3 comprises an error calculation part for calculating the error of 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 a PID algorithm, an adaptive control algorithm or a genetic algorithm.

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

[0022] Step 1: The MEMS resonator is formed into 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 the digital signals 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 a control algorithm, and transmit the control signal to two AD / DA modules 4-4;

[0025] Step 4: The two AD / DA modules 4-4 perform analog-to-digital conversion and amplification on the control signal, and finally apply the control signal to both ends of the joule heat module, so that the joule heat module generates resistance heat to maintain the temperature of the resonator constant;

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

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

[0028] This invention discloses a symmetrically suspended high-Q MEMS resonator and its isothermal control system and method. The MEMS resonator, through a symmetrical structural design, improves its electromechanical coupling coefficient. The suspension design suspends the resonator on a heat transfer frame, ensuring uniform heat transfer. Anchoring the MEMS resonator at fifth anchor points 2-3, sixth anchor points 2-6, and seventh anchor points 2-9 reduces residual stress from processing. Simultaneously, the MEMS resonator employs shear mode, which has a small stress gradient during vibration, reducing thermoelastic losses. The suspension structure further reduces coupling between the resonator body and the substrate, minimizing energy dissipation through the anchor points during vibration and improving the Q value. Furthermore, using frequency error as a criterion, the heating efficiency of the Joule heating module is actively controlled to maintain a constant temperature for the MEMS resonator, achieving high-precision, low-power, and low-cost temperature compensation. Ultimately, through these four design aspects, the stability of the MEMS resonator's output frequency is improved. Attached Figure Description

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

[0030] Figure 2 This is a schematic diagram illustrating the temperature regulation capability of an embodiment of the present invention in an external environment of -40°C.

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

[0032] Figure 4 This is a schematic diagram of the constant temperature control system according to an embodiment of the present invention.

[0033] Figure 5 A flowchart of the control method for the constant temperature control system in this invention.

[0034] In the figure: 1-1 is a first connecting beam; 1-2 is a first metal electrode layer; 1-3 is a first fixed support anchor point; 1-4 is a first resonator body; 1-5 is a second connecting beam; 1-6 is a second fixed support anchor point; 1-7 is a second metal electrode layer; 1-8 is a third connecting beam; 1-9 is a third fixed support anchor point; 1-10 is a third metal electrode layer; 1-11 is a fourth connecting beam; 1-12 is a first heat transfer frame; 1-13 is a fourth metal electrode layer; 1-14 is a fourth fixed support anchor point; 2-1 is a first anchor beam; 2-2 is a fifth metal electrode layer; 2-3 is a fifth fixed support anchor point; 2-4 is a first micro-resistance beam; 2-5 is a sixth metal electrode layer; 2-6 is a sixth fixed support anchor point; 2-7 is a second anchor beam; 2-8 is a seventh metal electrode layer; 2-9 is a seventh fixed support anchor point; 2-10 is a second micro-resistance beam; 3-1 is an eighth fixed support anchor point; 3-2 is an eighth metal electrode layer; 3-3 is a fifth connecting beam; 3-4 is a ninth fixed support anchor point; 3-5 is a ninth metal electrode layer; 3-6 is a sixth connecting beam; 3-7 is a tenth fixed support anchor point; 3-8 is a tenth metal electrode layer; 3-9 is a seventh connecting beam; 3-10 is a second resonator body; 3-11 is an eleventh metal electrode layer; 3-12 is an eleventh fixed support anchor point; 3-13 is a second heat transfer frame; 3-14 is an 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 solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application and the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0036] A symmetric suspension type high-Q 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, and the essence is that the change of the environmental temperature will cause the change of the Young's modulus of the resonator, thereby causing the change of the resonant frequency of the resonator. Taking a disc type resonator as an example, the specific relationship is shown in formula (1).

[0037]

[0038] In formula (1), λ i is a modal constant, r is the radius of the circle, p is the density, s is the Poisson's ratio, AT is the temperature change, and TCE is the change of the Young's variable with the temperature.

[0039] It can be seen from formula (1) that as the temperature variation range of the resonator increases, the temperature difference ΔT will also increase, and eventually lead to an increase in the frequency variation of the resonator. The present application provides a symmetric suspension type high-Q MEMS resonator and a constant temperature control system and method thereof, which can realize accurate and uniform control of temperature and enable the MEMS resonator to output stable frequency signals.

[0040] As shown in Figure 1 A symmetric suspension type high-Q MEMS resonator, which is a disc type symmetric structure and has a lame mode as the working mode, specifically comprises a sixth fixed anchor point 2-6, a first anchoring beam 2-1 and a first heat transfer frame 1-12 are connected to the left side of the sixth fixed anchor point 2-6, a first connecting beam 1-1, a second connecting beam 1-5, a third connecting beam 1-8, a fourth connecting beam 1-11 and a first resonator body 1-4 are connected inside the first heat transfer frame 1-12, a first fixed anchor point 1-3, a second fixed anchor point 1-6, a third fixed anchor point 1-9 and a fourth fixed anchor point 1-14 are 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 arranged on the first fixed anchor point 1-3, the second fixed anchor point 1-6, the third fixed anchor point 1-9 and the fourth fixed anchor point 1-14, a second anchoring beam 2-7 and a second heat transfer frame 3-13 are connected to the right side of the sixth fixed anchor point 2-6, a fifth connecting beam 3-3, a sixth connecting beam 3-6, a seventh connecting beam 3-9, an eighth connecting beam 3-14 and a second resonator body 3-10 are connected inside the second heat transfer frame 3-13, an eighth fixed anchor point 3-1, a ninth fixed anchor point 3-4, a tenth fixed anchor point 3-7 and an eleventh fixed 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, 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 arranged on the eighth fixed anchor point 3-1, the ninth fixed anchor point 3-4, the tenth fixed anchor point 3-7 and the eleventh fixed anchor point 3-12, a first micro-resistance beam 2-4 and a fifth fixed anchor point 2-3 are connected to the upper side of the sixth fixed anchor point 2-6, a second micro-resistance beam 2-10 and a seventh fixed anchor point 2-9 are connected to the lower side of the sixth fixed anchor point 2-6, a fifth metal electrode layer 2-2, a sixth metal electrode layer 2-5 and a seventh metal electrode layer 2-8 are arranged 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, reduces the coupling between the resonator body and the substrate, and reduces the energy dissipated by the resonator through the anchor point during vibration; the MEMS resonator adopts a shear mode, reduces the thermal-elastic loss of the resonator, improves the Q value of the resonator, and improves the stability of the output frequency of the MEMS resonator.

[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 uniformly transmitted to the resonator body through the anchor beam and the heat transfer frame to maintain the temperature of the MEMS resonator constant; 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 for driving the resonator; 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 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 type, the first fixed support anchor point 1-3, the first metal electrode layer 1-2, the second fixed support anchor point 1-6, the second metal electrode layer 1-7, the third fixed support anchor point 1-9, the third metal electrode layer 1-10, the fourth fixed support anchor point 1-14, and the fourth metal electrode layer 1-13 form a 3μm spacing with the first resonator body 1-4; the eighth fixed support anchor point 3-1, the eighth metal electrode layer 3-2, the ninth fixed support anchor point 3-4, the ninth metal electrode layer 3-5, the tenth fixed support anchor point 3-7, the tenth metal electrode layer 3-8, the eleventh fixed support anchor point 3-12, and the eleventh metal electrode layer 3-11 form a 3μm spacing with the second resonator body 3-10; a parallel plate capacitor is formed, and the resonator can be excited and detected through the parallel plate capacitor.

[0044] As shown in Figure 2 , the MEMS resonator of the present embodiment is modeled using the Joule heat and thermal expansion module in COMSOL Multiphysics, and the Joule heat effect of the MEMS resonator is simulated under the most extreme condition of the working environment of the MEMS resonator, i.e. the external environment is-40℃; from Figure 2As can be seen from the table, when the external environment is-40℃, the MEMS resonator of the embodiment can realize temperature adjustment from-40℃ to 85℃, and make the resonator be heated uniformly.

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

[0046] As shown in Figure 3 As shown in the embodiment (b), the thermoelastic quality factor Q of the MEMS resonator under the isothermal boundary condition is calculated by means of COMSOL Multiphysics. TED In the simulation result, the temperature distribution of the shear mode is more uniform in the vibration process, and therefore has a Q 8 of up to 5.9386×10 TED ; and the bulk mode has larger stress gradient and larger thermoelastic loss, and its Q TED is 3.9810×10 7 .

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

[0048]

[0049] In formula (2), f is the resonance frequency, p is the density, c is the sound speed, c D is the Debye velocity, g eff is the effective Grüneisen parameter, k 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 , and the embodiment reduces the anchor loss by adopting a suspension structure design, reduces the thermoelastic loss by adopting a shear mode, and the Q value of the actual MEMS resonator can reach 2.751×10 6 , which is very close to the quantum limit of the quality factor of the resonator.

[0051] As shown in Figure 4 A constant temperature control system of a symmetric suspension type high-Q MEMS resonator, comprising:

[0052] Two closed loop oscillation circuits 4-1: one closed loop oscillation circuit 4-1 input and the first metal electrode layer 1-2, the second metal electrode layer 1-7, the third metal electrode layer 1-10, the fourth metal electrode layer 1-13 outside the first resonator body 1-4 are connected; the other closed loop oscillation circuit 4-1 input and the eighth metal electrode layer 3-2, the ninth metal electrode layer 3-5, the tenth metal electrode layer 3-8, the eleventh metal electrode layer 3-11 are connected, 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 two frequency reading modules 4-2 input are respectively connected with the two closed loop oscillation circuit 4-1 output, 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 two frequency reading module 4-2 output are respectively connected with the two control modules 4-3, and the two control modules 4-3 are used to process the frequency signal and generate the control signal for controlling the temperature;

[0055] Two AD / DA modules 4-4: the two control module 4-3 output are respectively connected with the two AD / DA module 4-4 input, and the two AD / DA module 4-4 output are respectively connected with the fifth metal electrode layer 2-2, the seventh metal electrode layer 2-8, and the two AD / DA module 4-4 are used to convert the control signal to digital signal and amplify.

[0056] The closed loop oscillation circuit 4-1 includes an amplitude amplifier for amplifying the amplitude of the resonator response, a phase adjuster for adjusting the loop phase information, a signal controller for amplifying the detection signal and filtering out the stray signal 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-to-digital conversion part for converting the detection signal to a digital signal.

[0058] The control module 4-3 includes an error calculation part for calculating the error of 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 a PID algorithm, an adaptive control algorithm or a genetic algorithm.

[0061] As Figure 5As shown, the control method of the constant temperature control system based on the one kind of symmetric suspension type high Q value MEMS resonator comprises the following steps:

[0062] Step 1, the MEMS resonator forms self-excitation 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 the frequency change to two control modules 4-3 after analog-to-digital conversion;

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

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

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

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

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

[0069] The signal generated by the amplitude amplifier in the two closed loop oscillation circuits 4-1 will be divided into two paths, one of which will be fed back to the excitation electrode to form self-excitation oscillation of the MEMS resonator, and the other of which will be sent as a detection signal 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 the digital signal to two control modules 4-3, the two control modules 4-3 process the transmitted digital signal, compare the digital signal with a set signal through a related algorithm such as PID and fuzzy PID, calculate the frequency signal deviation, and determine whether the deviation is within the allowed range, if the deviation is within the allowed range, the output is performed after the frequency is stable, if the deviation is not within the allowed 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, the digital signals are converted into analog signals, and the analog signals are amplified to a certain extent, and finally applied to the two ends of the joule heat module. The joule heat module generates resistance heat through current, and the resistance heat is uniformly transmitted to the resonator through the anchor beam and the heat transfer frame, thereby realizing temperature control of the MEMS resonator.

[0072] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A symmetrically suspended high-Q MEMS resonator, characterized by: The disc type symmetrical structure has a lame mode, and includes a sixth fixed anchor point (2-6), and the left and right sides of the sixth fixed anchor point (2-6) are connected through a first anchor beam (2-1), a second anchor beam (2-7) and a first heat transfer frame (1-12), a second heat transfer frame (3-13); a first resonator body (1-4) is connected in the first heat transfer frame (1-12) 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 in the first heat transfer frame (1-12); a second resonator body (3-10) is connected in the second heat transfer frame (3-13) through 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 anchor point (2-6) are connected through a first micro-resistance beam (2-4), a second micro-resistance beam (2-10) and a fifth fixed anchor point (2-3), a seventh fixed anchor point (2-9); 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 anchor point (1-3), a second fixed anchor point (1-6), a third fixed anchor point (1-9) and a fourth fixed anchor point (1-14), and the first fixed anchor point (1-3), the second fixed anchor point (1-6), the third fixed anchor point (1-9) and the fourth fixed 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 (3-14) are respectively provided with an eighth fixed anchor point (3-1), a ninth fixed anchor point (3-4), a tenth fixed anchor point (3-7) and an eleventh fixed anchor point (3-12), and the eighth fixed anchor point (3-1), the ninth fixed anchor point (3-4), the tenth fixed anchor point (3-7) and the eleventh fixed 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 fixed anchor point (2-3), the sixth fixed anchor point (2-6) and the seventh fixed 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); The first resonator body (1-4) and the second resonator body (3-10) are square disc type, the first fixed anchor point (1-3), the first metal electrode layer (1-2), the second fixed anchor point (1-6), the second metal electrode layer (1-7), the third fixed anchor point (1-9), the third metal electrode layer (1-10), the fourth fixed anchor point (1-14) and the fourth metal electrode layer (1-13) are spaced apart from the first resonator body (1-4) by 3 microns; The eighth fixed anchor point (3-1), the eighth metal electrode layer (3-2), the ninth fixed anchor point (3-4), the ninth metal electrode layer (3-5), the tenth fixed anchor point (3-7), the tenth metal electrode layer (3-8), the eleventh fixed anchor point (3-12) and the eleventh metal electrode layer (3-11) are spaced apart from the second resonator body (3-10) by 3 microns; and a parallel plate capacitor is formed, and the resonator is excited and detected through the parallel plate capacitor.

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

3. The thermostatic control system of a symmetrically suspended high Q MEMS resonator according to claims 1-2, characterized in that, It comprises: Two closed loop oscillation circuits (4-1): one closed loop oscillation circuit (4-1) is connected with 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) is connected with 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 closed loop oscillation of the MEMS resonator; Two frequency reading modules (4-2): the two frequency reading modules (4-2) are connected with the outputs of the two closed loop oscillation circuits (4-1), respectively, and are used to read frequency signals of the resonator; Two control modules (4-3): the outputs of the two frequency reading modules (4-2) are connected with the two control modules (4-3), respectively, and the two control modules (4-3) are used to process the frequency signals and generate control signals for controlling temperature; Two AD / DA modules (4-4): two control modules (4-3) output respectively and two AD / DA modules (4-4) input connection, two AD / DA modules (4-4) output respectively and the fifth metal electrode layer (2-2), the seventh metal electrode layer (2-8) connection, two AD / DA modules (4-4) for control signal is converted to digital and analog, and amplification.

4. The constant temperature control system of a symmetrically suspended high Q MEMS resonator according to claim 3, wherein, The closed loop oscillation circuit (4-1) includes an amplitude amplifier for amplifying the amplitude of the resonator response, a phase adjuster for adjusting the loop phase information, and a signal controller for amplifying the detection signal. The MEMS resonator is used to generate a frequency signal in the closed loop oscillation circuit.

5. The constant temperature control system of a symmetrically suspended high Q MEMS resonator according to claim 3, wherein: The frequency reading module (4-2) includes a frequency reading part for real-time reading of the frequency change of the MEMS resonator, and an analog-to-digital conversion part for converting the detection signal to a digital signal.

6. The thermostatic control system of a symmetrically suspended high Q MEMS resonator according to claim 3, wherein: The control module (4-3) includes an error calculation part for calculating the error of the detection signal and the set frequency, and a control algorithm part for generating a control signal to control the thermal efficiency of the joule heat module.

7. The constant temperature control system of a symmetrically suspended high Q MEMS resonator according to claim 3, wherein: 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.

8. The control method of the constant temperature control system of the symmetric suspension type high Q-value MEMS resonator according to any one of claims 4 to 7, characterized by, The method comprises the following steps: 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 the digital signal to two control modules (4-3) after analog-to-digital conversion; Step 3: 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 two AD / DA modules (4-4); Step 4: two AD / DA modules (4-4) convert the control signal to digital and analog, and finally apply it to the two ends of the joule heat module, so that the joule heat 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 and control the temperature of the MEMS resonator to realize stable output of the resonator frequency.

Images