Resonator device and preparation method thereof, and filter

Abstract

The embodiment of the invention provides a resonator device, a preparation method thereof and a filter. The resonator device comprises a film bulk acoustic wave resonance structure, a thermistor and a direct-current voltage source, two ends of the film bulk acoustic wave resonance structure are respectively connected with a radio frequency input end and a radio frequency output end of the radio frequency circuit; the thermistor is connected in series with the direct-current voltage source and then is connected in parallel with the two ends of the film bulk acoustic wave resonance structure; and the film bulk acoustic wave resonance structure, the thermistor and the direct-current voltage source form a direct-current loop.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of wireless communication technology, and in particular to a resonator device and a preparation method thereof, and a filter. Background Art

[0002] The structure of a Film Bulk Acoustic Resonator (FBAR) resonator generally includes upper and lower electrodes and a piezoelectric film (e.g., piezoelectric materials such as lithium niobate or aluminum zirconia) therebetween. When an external electric field is applied to the upper and lower electrodes, the electric field will cause stress in the piezoelectric film, which in turn causes the piezoelectric effect of the piezoelectric film, causing the piezoelectric film to vibrate with acoustic waves to achieve resonance at a specific frequency. FBAR resonators have been widely used in the radio frequency field due to their high frequency, high quality factor, and small size.

[0003] However, the resonant frequency of the FBAR resonator is easily drifted due to changes in the external ambient temperature, which greatly reduces the reliability of the FBAR resonator in RF applications. Summary of the invention

[0004] In view of this, embodiments of the present application provide a resonator device and a method for preparing the same, and a filter.

[0005] To achieve the above purpose, the technical solution of the embodiment of the present application is implemented as follows:

[0006] The embodiment of the present application provides a resonator device, comprising: a thin film bulk acoustic wave resonator structure, a thermistor and a DC voltage source;

[0007] Two ends of the film bulk acoustic wave resonator structure are respectively connected to a radio frequency input end and a radio frequency output end of a radio frequency circuit;

[0008] After being connected in series with the DC voltage source, the thermistor is connected in parallel to both ends of the thin film bulk acoustic wave resonator structure; the thin film bulk acoustic wave resonator structure, the thermistor and the DC voltage source form a DC circuit.

[0009] In some embodiments, the DC voltage source has a preset output voltage; the thin film bulk acoustic wave resonator structure has a first divided voltage; the thermistor has a second divided voltage; and the first divided voltage has a first corresponding relationship with the temperature.

[0010] In some embodiments, the first corresponding relationship includes:

[0011] The first divided voltage is determined according to the product of a first voltage temperature coefficient of the thin film bulk acoustic wave resonator structure and a temperature variation.

[0012] In some embodiments, the first voltage temperature coefficient is related to a piezoelectric material of the FBAR structure.

[0013] In some embodiments, the first voltage temperature coefficient is determined by the following formula:

[0014]

[0015] Among them, A is the first voltage temperature coefficient; α is the thermal expansion coefficient of the piezoelectric material in the thickness direction; c0 is the elastic constant of the piezoelectric material; d0 is the piezoelectric strain constant of the piezoelectric material; ε0 is the dielectric constant of the piezoelectric material; h0 is the piezoelectric stiffness constant of the piezoelectric material; N is the electrostrictive coefficient of the piezoelectric material; R is the nonlinear change coefficient of the stiffness of the piezoelectric material.

[0016] In some embodiments, the second divided voltage has a second corresponding relationship with temperature, and the preset output voltage is determined by the first divided voltage and the second divided voltage.

[0017] In some embodiments, the second corresponding relationship includes: the second divided voltage is determined according to the product of a second voltage temperature coefficient of the thermistor and a temperature variation.

[0018] In some embodiments, the resonator device further comprises: a first capacitor and a second capacitor; after the thermistor is connected in series with the DC voltage source, the nodes connected to the thin film bulk acoustic wave resonator structure are the first node and the second node;

[0019] A first end of the first capacitor is connected to the RF input end, and a second end of the first capacitor is connected to a first end of the thin film bulk acoustic wave resonator structure through the first node;

[0020] The first end of the second capacitor is connected to the second end of the thin film bulk acoustic wave resonator structure through the second node, and the second end of the second capacitor is connected to the radio frequency output end.

[0021] In some embodiments, the first capacitor and / or the second capacitor is located in a cavity between the FBAR structure and a substrate.

[0022] In some embodiments, the nodes where the thermistor and the DC voltage source are connected in series and are connected to the FBAR structure are a first node and a second node;

[0023] The resonator device further comprises a first inductor and a second inductor, wherein the first inductor and the second inductor are used to block the radio frequency signal from flowing out to the DC circuit;

[0024] The thermistor and the DC voltage source connected in series are respectively connected to the first node via the first inductor and connected to the second node via the second inductor.

[0025] In some embodiments, the first inductor and / or the second inductor is located in a cavity between the FBAR structure and a substrate.

[0026] In some embodiments, after the thermistor is connected in series with the DC voltage source, it is connected in parallel to both ends of the thin film bulk acoustic wave resonator structure to form a first node and a second node in the radio frequency circuit;

[0027] The thermistor includes a first resistor and a second resistor;

[0028] Two ends of the DC voltage are respectively connected to the first node through the first resistor, and connected to the second node through the second resistor.

[0029] The embodiment of the present application also provides a filter, comprising: a thin film bulk acoustic wave resonator unit, a thermistor and a DC voltage source;

[0030] The film bulk acoustic wave resonance unit includes a film bulk acoustic wave resonance structure or a plurality of cascaded film bulk acoustic wave resonance structures;

[0031] The signal input end and the signal output end of the film bulk acoustic wave resonator unit are respectively connected to the radio frequency input end and the radio frequency output end of the radio frequency circuit; the thermistor is connected in series with the DC voltage source and then connected in parallel with the film bulk acoustic wave resonator unit;

[0032] Wherein, the thin film bulk acoustic wave resonator unit, the thermistor unit and the DC voltage source form a DC circuit;

[0033] Alternatively, the filter comprises a resonator device as described above.

[0034] The present application also provides a method for preparing a resonator device, including:

[0035] determining a third corresponding relationship between the resonator voltage and the temperature according to the thin film bulk acoustic wave resonance structure;

[0036] determining a fourth correspondence between a resistance voltage and a temperature of at least one thermistor;

[0037] Selecting the thermistor according to the third corresponding relationship and the fourth corresponding relationship, and determining the DC voltage source;

[0038] Among them, the first end of the thin film bulk acoustic wave resonance structure is connected to the RF input end, and the second end is connected to the RF output end; the RF input end, the thin film bulk acoustic wave resonance structure and the RF output end form an AC signal path; the first end of the thermistor is connected to the RF input end or the RF output end, and the second end is connected to the DC voltage source; the thin film bulk acoustic wave resonance structure, the thermistor and the DC voltage source form a DC circuit.

[0039] In some embodiments, determining a third corresponding relationship between a resonant structure voltage and a temperature according to the thin film bulk acoustic wave resonator structure includes:

[0040] Determining the third corresponding relationship between the voltage and temperature of the resonant structure according to the first voltage temperature coefficient of the thin film acoustic wave resonant structure;

[0041] The first voltage temperature coefficient is related to the piezoelectric material of the thin film bulk acoustic wave resonance structure.

[0042] In some embodiments, determining the third corresponding relationship between the voltage and temperature of the resonant structure according to the first voltage temperature coefficient of the thin film acoustic wave resonant structure includes:

[0043] determining the first voltage temperature coefficient according to the thermal expansion coefficient in the thickness direction of the piezoelectric material, the elastic constant of the piezoelectric material, the piezoelectric strain constant of the piezoelectric material, the dielectric constant of the piezoelectric material, the piezoelectric constant of the piezoelectric material, the electrostriction coefficient of the piezoelectric material and the nonlinear variation coefficient of the stiffness of the piezoelectric material;

[0044] The third corresponding relationship between the voltage of the resonant structure and the temperature is determined according to the first voltage temperature coefficient.

[0045] In some embodiments, selecting the thermistor according to the third corresponding relationship and the fourth corresponding relationship and determining the DC voltage source includes:

[0046] Selecting the thermistor according to the third corresponding relationship and the fourth corresponding relationship;

[0047] The output voltage of the DC voltage source is determined according to the resistance voltage corresponding to the selected thermistor and the resonator voltage.

[0048] The resonator device provided in the embodiment of the present application adds a thermistor and a DC voltage source at both ends of the thin film bulk acoustic wave resonant structure, so that the thin film bulk acoustic wave resonant structure, the thermistor and the DC voltage source form a DC circuit. Utilizing the characteristic that the resistance value of the thermistor changes with temperature, when the ambient temperature changes, the voltage division of the thermistor in the DC circuit changes with the resistance value, thereby automatically adjusting the DC bias of the thin film bulk acoustic wave resonant structure in the DC circuit. The frequency offset of the thin film bulk acoustic wave resonant structure caused by the DC bias can offset or partially offset the frequency drift caused by temperature changes, which can effectively enhance the temperature stability of the thin film bulk acoustic wave resonant structure and the resonator device. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the structure of a resonator device provided in an embodiment of the present application;

[0050] Figure 2 A circuit diagram of a resonator device provided in an embodiment of the present application Figure 1 ;

[0051] Figure 3 The temperature-voltage curve of the thin film bulk acoustic wave resonance structure provided in the embodiment of the present application;

[0052] Figure 4 A circuit diagram of a resonator device provided in an embodiment of the present application Figure 2 ;

[0053] Figure 5 A circuit diagram of a resonator device provided in an embodiment of the present application Figure 3 ;

[0054] Figure 6 A structural view of the resonator device provided in the embodiment of the present application Figure 1 ;

[0055] Figure 7 A circuit diagram of a resonator device provided in an embodiment of the present application Figure 4 ;

[0056] Figure 8 A structural view of the resonator device provided in the embodiment of the present application Figure 2 ;

[0057] Fig. 9 A circuit diagram of a resonator device provided in an embodiment of the present application Figure 5 ;

[0058] Fig.10 A schematic diagram of the resistance temperature change of the thermistor provided in an embodiment of the present application;

[0059] Fig.11 A circuit diagram of a resonator device provided in an embodiment of the present application Figure 6 ;

[0060] Fig.12 A schematic diagram of the structure of the filter provided in the embodiment of the present application;

[0061] Fig.13 A circuit diagram of a filter provided in an embodiment of the present application;

[0062] Fig.14 A schematic diagram of the steps for preparing a resonator device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The following will be combined with the embodiments of the present application and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0064] In the following description, a large number of specific details are given to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features known in the art are not described; that is, all features of the actual embodiments are not described here, and well-known functions and structures are not described in detail.

[0065] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0066] In order to thoroughly understand the present application, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0067] The resonant frequency of the FBAR resonator is prone to drift due to changes in the external ambient temperature. Temperature changes can cause changes in the center frequency, insertion loss and other performance of the FBAR filter, especially at the edge of the passband. If the temperature rises, the filter will have an overall low frequency deviation (the curve is biased to the left as a whole), and the loss at the right side of the passband will deteriorate seriously. If the temperature drops, the filter will have an overall high frequency deviation (the curve is biased to the right as a whole), and the loss at the left side of the passband will deteriorate seriously. It can be seen that temperature changes greatly reduce the reliability of FBAR resonators in RF applications.

[0068] In view of this, an embodiment of the present application provides a resonator device, such as Figure 1 As shown, the resonator device 100 includes: a thin film bulk acoustic wave resonator structure 101, a thermistor 102 and a DC voltage source 103;

[0069] Two ends of the film bulk acoustic wave resonator structure 101 are respectively connected to the radio frequency input end and the radio frequency output end of the radio frequency circuit;

[0070] The thermistor 102 and the DC voltage source 103 are connected in series and then connected in parallel to two ends of the FBAR structure 101 . The FBAR structure 101 , the thermistor 102 and the DC voltage source 103 form a DC loop.

[0071] The RF input (RFIN) and RF output (RFOUT) terminals are ports for RF signals to enter and leave the RF circuit, respectively. The RF signal input to the RFIN terminal is processed by the FBAR structure 101 and then output from the RFOUT terminal.

[0072] The DC voltage source 103 is a device that can provide a DC voltage. The resistance value of the thermistor 102 and the resonant frequency of the film bulk acoustic wave resonator structure 101 are both affected by the ambient temperature. For example, the resistance value of the thermistor 102 with a negative temperature coefficient decreases as the temperature increases. The resonant frequency of the film bulk acoustic wave resonator structure 101 decreases as the temperature increases.

[0073] Continue to refer Figure 1, the DC voltage source 103 provides a DC bias (DC Bias) to the thermistor 102 and the film bulk acoustic wave resonant structure 101 in the DC circuit respectively. When the ambient temperature rises, the resistance value of the thermistor 102 decreases, thereby reducing the voltage component provided to the thermistor 102 and increasing the voltage component provided to the film bulk acoustic wave resonant structure 101. Since the DC bias at both ends of the film bulk acoustic wave resonant structure 101 increases, its resonant frequency increases, which can offset or partially offset the decrease in resonant frequency caused by the increase in temperature. When the ambient temperature decreases, the resistance value of the thermistor 102 increases, thereby increasing the voltage component provided to the thermistor 102 and reducing the voltage component provided to the film bulk acoustic wave resonant structure 101. Since the DC bias at both ends of the film bulk acoustic wave resonant structure 101 decreases, its resonant frequency decreases, which can offset or partially offset the increase in resonant frequency caused by the decrease in temperature. The temperature stability of the FBAW structure 101 and the resonator device 100 can be effectively enhanced by adding thermistors 102 and DC voltage sources 103 at both ends of the FBAW structure 101 .

[0074] The resonator device 100 provided in the embodiment of the present application is provided with a thermistor 102 and a DC voltage source 103 at both ends of the thin film bulk acoustic wave resonant structure 101, so that the thin film bulk acoustic wave resonant structure 101, the thermistor 102 and the DC voltage source 103 form a DC circuit. Utilizing the characteristic that the resistance value of the thermistor 102 changes with temperature, when the ambient temperature changes, the voltage division of the thermistor 102 in the DC circuit changes with the resistance value, thereby automatically adjusting the DC bias of the thin film bulk acoustic wave resonant structure 101 in the DC circuit. The frequency offset of the thin film bulk acoustic wave resonant structure 101 caused by the DC bias can offset or partially offset the frequency drift caused by the temperature change, which can effectively enhance the temperature stability of the thin film bulk acoustic wave resonant structure 101 and the resonator device 100.

[0075] In some embodiments, the DC voltage source 103 has a preset output voltage; the FBAR structure has a first divided voltage; the thermistor has a second divided voltage; and the first divided voltage U1 has a first corresponding relationship with the temperature.

[0076] The first voltage division refers to the voltage across the FBAR structure 101 under normal working conditions. The second voltage division refers to the voltage across the thermistor 102 under normal working conditions. The output voltage of the DC voltage source 103 can be a preset fixed value, or a non-fixed value having a preset corresponding relationship with the temperature.

[0077] In a specific embodiment, if Figure 2As shown, the resonator device includes a thermistor 102, and the first end of the thermistor 102 is connected to the radio frequency input terminal RFIN and the first end of the film bulk acoustic wave resonator structure 101, that is, the first end of the thermistor 102 is connected to the first node N1 between the radio frequency input terminal RFIN and the film bulk acoustic wave resonator structure 101. The second end of the thermistor 102 is connected to the first end of the DC voltage source 103. The second end of the DC voltage source 103 is connected to the radio frequency output terminal RTOUT and the second end of the film bulk acoustic wave resonator structure 101, that is, the other end of the DC voltage source 103 is connected to the second node N2 between the radio frequency output terminal RTOUT and the film bulk acoustic wave resonator structure 101. The preset output voltage of the DC voltage source 103 is equal to the sum of the first partial voltage U1 at both ends of the film bulk acoustic wave resonator structure 101 and the second partial voltage U2 at both ends of the thermistor. Among them, the first partial voltage U1 has a first corresponding relationship with the temperature. Exemplarily, within the operating temperature range of the film bulk acoustic wave resonator structure 101, the first partial voltage U1 increases with the increase of temperature. Thus, when the temperature rises, the first partial voltage U1 across the FBAW structure 101 also increases. The resonant frequency of the FBAW structure 101 increases due to the DC bias voltage, which can offset or partially offset the decrease in resonant frequency caused by the temperature increase.

[0078] It should be noted that the embodiment of the present application does not limit the specific connection mode of the DC voltage source 103, that is, the first end of the DC voltage source 103 can be a positive electrode or a negative electrode. The embodiment of the present application also does not limit the specific connection mode of the thermistor, as long as the thermistor 102 is connected between the DC voltage source 103 and the first node N1, or between the DC voltage source 103 and the second node N2.

[0079] In some embodiments, the first corresponding relationship includes:

[0080] The first divided voltage U1 is determined according to the product of the first voltage temperature coefficient A of the FBAR structure 101 and the temperature variation ΔT.

[0081] The first voltage temperature coefficient A of the FBAR structure 101 depends on the specific parameters of the FBAR structure 101, and can be calculated based on the specific parameters or obtained through experimental testing. The first voltage division U1 is related to the product of the first voltage temperature coefficient A of the FBAR structure 101 and the temperature variation ΔT.

[0082] In a specific embodiment, continue to refer to Figure 2 , the first voltage division U1 satisfies: U1=U S1 +ΔU1=U S1 +A*ΔT=U S1 +A*(T1-T0). Where T1 represents the current temperature and T0 represents the reference temperature.S1 It means that under the reference temperature T0, the first partial pressure of the thin film bulk acoustic wave resonator structure 101 is equal to U S1 At this time, the film bulk acoustic wave resonator structure 101 has a target resonant frequency. When the temperature increases by ΔT, the first partial pressure increases by ΔU1, and the film bulk acoustic wave resonator structure has a target resonant frequency. S1 +ΔU1 condition, the increased DC bias ΔU1 increases the resonant frequency of the film bulk acoustic wave resonance structure, offsetting the decrease in the resonant frequency of the film bulk acoustic wave resonance structure caused by the increased temperature ΔT.

[0083] It should be noted that the DC bias voltage U1 provided by the DC voltage source 103 to both ends of the FBAR structure 101 can at least partially correct the frequency deviation of the FBAR structure 101 caused by temperature, that is, U1 satisfies U S1 <U1≤U S1 +ΔU1 will do.

[0084] In some embodiments, the first voltage temperature coefficient A is related to the piezoelectric material of the FBAR structure.

[0085] Among them, the first voltage temperature coefficient A is related to at least one of the thermal expansion coefficient α in the thickness direction of the piezoelectric material, the elastic constant c0 of the piezoelectric material, the piezoelectric strain constant d0 of the piezoelectric material, the dielectric constant ε0 of the piezoelectric material, the piezoelectric constant h0 of the piezoelectric material, the electrostrictive coefficient N of the piezoelectric material, and the nonlinear change coefficient R of the stiffness of the piezoelectric material.

[0086] In some embodiments, the first voltage temperature coefficient A may be determined by the series resonant frequency and / or parallel resonant frequency of the FBAR structure 101. The series resonant frequency refers to the resonant frequency of the FBAR in the series resonant state, and the parallel resonant frequency refers to the resonant frequency of the FBAR in the parallel resonant state.

[0087] Taking the parallel resonant frequency as an example, the parallel resonant frequency f can be expressed by the following formula (1):

[0088]

[0089] Among them, v is the longitudinal wave sound velocity propagating along the thickness direction of the piezoelectric material; t is the thickness of the piezoelectric material; c is the piezoelectric elastic constant; e is the piezoelectric constant, ε is the piezoelectric dielectric constant; ρ is the piezoelectric density.

[0090] When the FBAR structure is subjected to an additional DC bias voltage ΔU1, the elastic constant and thickness of the piezoelectric material change. At the same time, the elastic constant c and thickness t in formula (1) are fully differentiated, and the normalized frequency drift is It is used to measure the degree of frequency drift and can be specifically expressed by the following formula (2):

[0091]

[0092] Among them, Δf is the change in frequency drift, f0 is the frequency under initial conditions (initial DC bias); Δc is the change in piezoelectric elastic constant, c0 is the initial value of the piezoelectric elastic constant; Δt is the change in the thickness of the piezoelectric material layer, t0 is the initial value of the thickness of the piezoelectric material layer.

[0093] In the above formula (2), and They can be expressed by the following formulas (3-4):

[0094]

[0095] Among them, d0 is the piezoelectric strain constant of the piezoelectric material; ε0 is the dielectric constant of the piezoelectric material; h0 is the piezoelectric stiffness constant of the piezoelectric material; N is the electrostrictive coefficient of the piezoelectric material; R is the nonlinear variation coefficient of the stiffness of the piezoelectric material; ΔU1 is the additional DC bias voltage applied to the thin film bulk acoustic wave resonance structure.

[0096] Then, when the FBAR structure is subjected to an additional DC bias ΔU1, the normalized frequency drift is It can be expressed by the following formula (5):

[0097]

[0098] In addition, when the thin film acoustic wave resonator structure is subjected to temperature changes, the thickness of the piezoelectric material changes. The normalized frequency drift is obtained by taking the total differential of the thickness t in formula (1). It is used to measure the degree of frequency drift and can be specifically expressed by the following formula (6):

[0099]

[0100] Among them, Δf is the frequency drift change, f0 is the frequency under the initial condition (initial temperature); Δt is the thickness change of the piezoelectric material layer, and t0 is the initial value of the thickness of the piezoelectric material layer.

[0101] Combining the above formula (5) and formula (6), when the frequency offset caused by the DC bias change and the frequency offset caused by the temperature change can offset each other, the following formula (7) is satisfied:

[0102]

[0103] Furthermore, the voltage coefficient of frequency (Voltage Coefficient of Frequency, VCF) of the thin film bulk acoustic wave resonator structure can be determined according to the above formula (5):

[0104]

[0105] According to the above formula (6), the temperature coefficient of frequency (TCF) of the thin film bulk acoustic wave resonator structure can be determined:

[0106]

[0107] Then, when the frequency offset caused by the DC bias change and the frequency offset caused by the temperature change can offset each other, the following formula (10) is satisfied:

[0108] VCF*ΔU1+TCF*ΔT=0 (10)

[0109] That is, the above formula (7) is satisfied; then, the first voltage temperature coefficient A is expressed by the following formula (11):

[0110]

[0111] That is, the first voltage temperature coefficient A of the thin film bulk acoustic wave resonator structure 101 can be determined based on the thermal expansion coefficient α in the thickness direction of the piezoelectric material, the elastic constant c0 under initial conditions, the piezoelectric strain constant d0, the dielectric constant ε0, the piezoelectric constant h0, and the electrostrictive coefficient N and the nonlinear variation coefficient R of the stiffness.

[0112] The best situation is when the above formula (7) or (10) is satisfied, that is, the frequency shift caused by the DC bias ΔU1 applied to the FBAR structure 101 just offsets the frequency shift caused by the temperature ΔT.

[0113] In some other embodiments, the frequency voltage coefficient VCF and the frequency temperature coefficient TCF may satisfy the following formula (12).

[0114] |VCF*ΔU1+TCF*ΔT|<|TCF*ΔT| (12)

[0115] That is, the frequency shift caused by the DC bias ΔU1 can at least partially offset the frequency shift caused by the temperature ΔT.

[0116] In other embodiments, the first voltage temperature coefficient A can be obtained through a large number of experiments. Specifically, the frequency can be used as intermediate data, and a database can be established by obtaining the frequency data of the thin film bulk acoustic wave resonator structure 101 under different first partial pressures U1 and the frequency data under different temperatures obtained through experiments, and the first voltage temperature coefficient A of the thin film bulk acoustic wave resonator structure 101 can be obtained through data rules; in addition, a database of DC bias voltage and temperature can also be obtained, and a related curve relationship can be established.

[0117] Exemplarily, the first voltage temperature coefficient A may be determined by the following method:

[0118] Taking a certain resonator device product as an example, at least the frequency data of the film bulk acoustic wave resonator structure 101 in the temperature range of -40°C to 150°C is determined through experiments. The obtained frequency data is fitted to obtain a frequency temperature curve, and the frequency temperature coefficient TCF can be obtained according to the frequency temperature curve. In the frequency temperature curve of this embodiment, as the temperature increases, the resonant frequency of the film bulk acoustic wave resonator structure 101 decreases.

[0119] The frequency data of the thin film bulk acoustic wave resonator structure 101 under different DC biases are determined by experiments, wherein the range of the frequency change of the DC bias needs to cover the frequency shift caused by the temperature range of -40°C to 150°C as mentioned above, that is, the frequency shift range changed by the DC bias can cover the frequency drift range caused by temperature. The frequency voltage curve can be obtained, and the frequency voltage coefficient VCF can be determined.

[0120] By experimentally determining the frequency temperature coefficient TCF and the frequency voltage coefficient VCF, the first voltage temperature coefficient A=-TCF / VCF of the film bulk acoustic wave resonator structure 101 in this embodiment can be determined, and then the following is obtained: Figure 4 The relationship curve between DC bias and temperature is shown. Or the corresponding relationship between DC voltage and temperature can be obtained by converting the above-mentioned multiple sets of data: ΔU1=A*(T1-T0)=-TCF / VCF(T1-T0)=0.28(T-25). In this embodiment, the TCF value of the thin film bulk acoustic wave resonator structure 101 is -25ppm / ℃, and the room temperature is T0 is 25℃; the value of the bias frequency offset VCF of the product is 87ppm / V. Exemplarily, in order to make the frequency offset caused by the DC bias completely offset the frequency offset caused by temperature, when the temperature is monitored to 30℃, an additional DC bias of about 1.4V can be applied to compensate for the high temperature and low bias passband. It should be noted that the frequency temperature coefficient TCF value of the thin film bulk acoustic wave resonator structure 101 is -25ppm / ℃ for illustration only. The embodiment of the present application does not limit the frequency temperature coefficient TCF of the thin film bulk acoustic wave resonator structure 101. In some embodiments, the frequency temperature coefficient TCF includes -15 to -30ppm / ℃.

[0121] Alternatively, the fixed frequency insertion loss is used as the intermediate data, and the insertion loss data of the thin film bulk acoustic wave resonator structure 101 at different first partial pressures U1 and at different temperatures obtained through experiments are used to establish a database, and the first voltage temperature coefficient A of the thin film bulk acoustic wave resonator structure 101 is obtained through data rules.

[0122] In some embodiments, the second divided voltage U2 has a second corresponding relationship with the temperature, and the preset output voltage is determined by the first divided voltage U1 and the second divided voltage U2.

[0123] Exemplarily, within the operating temperature range of the thermistor 102, the second divided voltage U2 decreases as the temperature increases. The preset output voltage U OUT = U1 = U2 = 1 / ... OUT =U1+U2. When designing the DC voltage source 103 matching the thin film bulk acoustic wave resonator structure 101 and the thermistor 102, the output voltage U OUT Select a suitable DC voltage source 103 .

[0124] It should be noted that the DC voltage source 103 may be a constant voltage source, and its output voltage is always a fixed value.

[0125] In some other embodiments, the output voltage of the DC voltage source 103 may also be non-constant, that is, the DC voltage source 103 is a variable voltage source, and the variable voltage source can change the output according to the positive or negative bias voltage required by the FBAR structure 101 .

[0126] In some embodiments, the second corresponding relationship includes: the second divided voltage U2 is determined according to the product of the second voltage temperature coefficient B of the thermistor 102 and the temperature change ΔT.

[0127] The second voltage temperature coefficient B of the thermistor 102 depends on the specific parameters of the thermistor 102 and can be calculated based on the specific parameters or obtained through experimental testing. The second divided voltage U2 is related to the product of the second voltage temperature coefficient B and the temperature variation ΔT.

[0128] In a specific embodiment, the second divided voltage U2 satisfies U2=U S2 +ΔU2=U S2 +B*ΔT=U S2 +B*(T1-T0). The DC voltage source 103 has a constant output voltage. Figure 2 , under the reference temperature T0, the first partial pressure of the film bulk acoustic wave resonator structure 101 is equal to U S1 , the second voltage division of thermistor 102 is equal to U S2 The output voltage of the DC voltage source is always U OUT =U S1 +U S2 When the temperature increases by ΔT, the second voltage division across the thermistor 102 increases by B*ΔT, i.e., ΔU2. OUTis a constant value, the first partial pressure at both ends of the FBAR structure is reduced by ΔU2. At this time, the FBAR structure 101 is at U S1 -ΔU2. When the temperature rises by ΔT, the first partial pressure increases by ΔU1, and the first partial pressure at both ends of the thin film bulk acoustic wave resonance structure is U S1 +ΔU1, then when U S1 -ΔU2=U S1 When +ΔU1, -ΔU2=ΔU1, -B*ΔT=A*ΔT, that is, when A=-B, the DC bias is reduced by ΔU2, causing the resonant frequency shift of the thin film bulk acoustic wave resonance structure, which can offset the resonant frequency shift of the thin film bulk acoustic wave resonance structure caused by the increased temperature ΔT.

[0129] In some embodiments, the second voltage temperature coefficient B can be obtained through a large number of experiments. Specifically, a database can be established by testing multiple sets of data of thermistors 102 at different second divided voltages U2 and temperatures to obtain the second voltage temperature coefficient B of the thermistors 102.

[0130] In some embodiments, Figure 4 As shown, the resonator device 100 further includes: a first capacitor C1 and a second capacitor C2; after the thermistor 102 is connected in series with the DC voltage source 103, the nodes connected to the FBAR structure 101 are the first node N1 and the second node N2;

[0131] A first end of the first capacitor C1 is connected to the radio frequency input end (RFIN end), and a second end of the first capacitor C1 is connected to a first end of the thin film bulk acoustic wave resonator structure 101 through a first node N1;

[0132] A first end of the second capacitor C2 is connected to a second end of the FBAR structure 101 via a second node N2 , and a second end of the second capacitor C2 is connected to a radio frequency output end (RFOUT end).

[0133] The first capacitor C1 connected to the first node and the RFIN terminal can prevent the DC signal from leaking from the RFIN terminal, and the second capacitor connected to the second node and the RFOUT terminal can prevent the DC signal from leaking from the RFOUT terminal, resulting in the DC voltage source being unable to provide a suitable DC bias voltage for the thin film bulk acoustic wave resonator structure 101. The RF signal input to the RFIN terminal is processed by the first capacitor C1, the thin film bulk acoustic wave resonator structure 101 and the second capacitor C2 in sequence, and then output from the RFOUT terminal.

[0134] In a specific embodiment, if Figure 5As shown, the RF output terminal is connected to the antenna and the ground terminal. Since the second capacitor C2 is connected between the second node N2 and the RFOUT terminal, the DC signal will not leak due to the grounding of the RF output terminal, and the two ends of the thin film bulk acoustic wave resonance structure cannot generate bias, but the RF signal input at the RFIN terminal can still pass through the second capacitor to the antenna terminal.

[0135] In some embodiments, the first capacitor C1 and / or the second capacitor C2 are located in the cavity between the FBAR structure 101 and the substrate. Figure 6 As shown, the film bulk acoustic wave resonator structure 101 is arranged on one side of the substrate 800, and includes an upper electrode layer 801, a lower electrode layer 802 and a piezoelectric material layer 803 therebetween. There is a cavity between the substrate 800 and the film bulk acoustic wave resonator structure to form an air interface of the film bulk acoustic wave resonator structure 101. The cavity confines the sound wave in the piezoelectric material layer, which helps to improve the quality factor of the film bulk acoustic wave resonator structure 101. The first capacitor C1 and / or the second capacitor C2 are arranged in the cavity between the film bulk acoustic wave resonator structure 101 and the substrate, which is conducive to the miniaturization of the resonator device 100.

[0136] In some embodiments, Figure 7 As shown, the thermistor 102 and the DC voltage source 103 connected in series, and the nodes connected to the FBAR structure 101 are the first node N1 and the second node N2;

[0137] The resonator device 100 further includes a first inductor L1 and a second inductor L2, wherein the first inductor L1 and the second inductor L2 are used to block the radio frequency signal from flowing out to the DC circuit;

[0138] The thermistor 102 and the DC voltage source 103 connected in series are respectively connected to a first node N1 via a first inductor L1 and to a second node N2 via a second inductor L2.

[0139] The first inductor L1 and the second inductor L2 can prevent the RF signal from leaking from the first node N1 or the second node N2 to the DC path, thereby increasing the insertion loss of the FBAR structure 101. Moreover, when the current in the DC circuit is stable, the voltage component across the first inductor L1 and the second inductor L2 can be ignored.

[0140] In some embodiments, such as Figure 8 As shown, the first inductor L1 and / or the second inductor L2 are located in the cavity between the FBAR structure 101 and the substrate 800 , which is beneficial to the miniaturization of the resonator device 100 .

[0141] In some embodiments, Fig. 9As shown, after the thermistor 102 is connected in series with the DC voltage source 103, it is connected in parallel at both ends of the FBAR structure 101 to form a first node N1 and a second node N2 in the RF circuit;

[0142] The thermistor 102 includes a first resistor R1 and a second resistor R2;

[0143] Two ends of the DC voltage source 103 are respectively connected to a first node N1 through a first resistor R1 and connected to a second node N2 through a second resistor R2.

[0144] The sum of the voltage across the first resistor R1 and the voltage across the second resistor R2 is the second divided voltage U2. It should be noted that the embodiment of the present application does not limit the specific position of the thermistor 102 on the DC path, nor does it limit the specific number of thermistors, as long as the sum of the voltages across the thermistors in the DC path is equal to the second divided voltage U2.

[0145] In some embodiments, the material of the thermistor includes vanadium dioxide. Fig.10 As shown, the resistance temperature coefficient of the vanadium dioxide thermistor is negative. Its resistance value is within a certain range and gradually decreases with the increase of temperature. And the vanadium dioxide thermistor has a wide operating temperature range, such as -50℃ to 300℃, which can provide good stability performance.

[0146] In a specific embodiment, if Fig.11 As shown, the first capacitor C1 is connected between the first node and the RFIN terminal, and the second capacitor C2 is connected between the second node N2 and the RFOUT terminal. The first inductor L1 is connected between the first node N1 and the first resistor R1, and the second inductor L1 is connected between the second node N2 and the second resistor R2. The first capacitor C1 and the second capacitor C2 can prevent the DC signal from flowing out from the RFIN terminal and the RFOUT terminal respectively; the first inductor L1 and the second inductor L2 can prevent the AC signal from leaking from the first node N1 and the second node N2 from the DC path, causing the insertion loss of the thin film bulk acoustic wave resonator structure 101 to increase.

[0147] The present application also provides a filter, such as Fig.12 As shown, the filter 200 includes: a thin film bulk acoustic wave resonator unit 901, a thermistor 102 and a DC voltage source 103;

[0148] The FBAR unit 901 includes a FBAR structure 101 or a plurality of cascaded FBAR structures 101;

[0149] The signal input terminal and the signal output terminal of the FBAR unit 901 are respectively connected to the RF input terminal and the RF output terminal of the RF circuit; the thermistor 102 is connected in series with the DC voltage source 103 and then connected in parallel with the FBAR unit 901;

[0150] The FBAW unit 901 , the thermistor 102 and the DC voltage source 103 form a DC circuit.

[0151] Alternatively, the filter 200 comprises one or more resonator devices as described above.

[0152] In some embodiments, the FBAR unit 901 includes a FBAR structure 101. In other embodiments, Fig.13 As shown, the film bulk acoustic wave resonator unit 901 includes two film bulk acoustic wave resonator structures 101 connected in series. After the thermistor 102 is connected in series with the DC voltage source 103, it is connected in parallel with the film bulk acoustic wave resonator unit 901. When the ambient temperature increases (or decreases), the DC bias voltage provided by the DC voltage source 103 to the thermistor 102 decreases (or increases), and the DC bias voltage provided to each film bulk acoustic wave resonator structure 101 increases (or decreases). The increase (or decrease) of the DC bias voltage can offset or partially offset the frequency deviation caused by the increase (or decrease) of the ambient temperature.

[0153] The thermistor 102 can sense changes in ambient temperature and automatically adjust the DC bias of the film bulk acoustic wave resonator structure 101 connected in parallel thereto through the DC voltage source 103 to offset or partially offset the frequency shift of the film bulk acoustic wave resonator structure 101 caused by changes in ambient temperature. In addition, it should be noted that for multiple film bulk acoustic wave resonator structures cascaded in a radio frequency circuit, for example, an FBAR filter formed by cascading multiple film bulk acoustic wave resonator structures can provide DC bias to the film bulk acoustic wave resonator structures respectively by the same DC voltage source 103 or different DC voltage sources 103.

[0154] The DC voltage source 103 may be a constant voltage source or a variable voltage source. In some embodiments, the DC voltage source is a variable voltage source that can provide a voltage variation from -50V to 50V.

[0155] In addition, the embodiments of the present application do not limit the configuration of the thermistor 102 and the DC voltage source 103. They can be configured on a chip, or on a substrate or a mobile phone motherboard, and connected through an interface on the chip.

[0156] The present application also provides a method for preparing a resonator device, such as Fig.14 As shown, the preparation method comprises the following steps:

[0157] Step S101: determining a third corresponding relationship between a resonator voltage and a temperature according to a thin film bulk acoustic wave resonance structure.

[0158] Step S102: determining a fourth corresponding relationship between a resistance voltage and a temperature of at least one thermistor.

[0159] Step S103: selecting a thermistor according to the third corresponding relationship and the fourth corresponding relationship, and determining a DC voltage source.

[0160] Among them, the first end of the thin film bulk acoustic wave resonance structure is connected to the RF input end, and the second end is connected to the RF output end; the RF input end, the thin film bulk acoustic wave resonance structure and the RF output end form an AC signal path; the first end of the thermistor is connected to the RF input end or the RF output end, and the second end is connected to a DC voltage source; the thin film bulk acoustic wave resonance structure, the thermistor and the DC voltage source form a DC circuit.

[0161] By determining the third corresponding relationship between the resonator voltage and the temperature and the fourth corresponding relationship between the resistance voltage of the thermistor and the temperature, the sum of the change value of the resonator voltage and the change value of the resistance voltage under the same temperature change is equal to or approximately equal to zero. When the ambient temperature increases (or decreases), the resistance voltage of the thermistor 102 decreases (or increases), and the resonator voltage of the thin film bulk acoustic wave resonator structure increases (or decreases). The increase (or decrease) in the resonator voltage can offset or partially offset the frequency shift caused by the increase (or decrease) in the ambient temperature.

[0162] In some embodiments, in the above step S101, determining the third corresponding relationship between the voltage and temperature of the resonant structure according to the thin film bulk acoustic wave resonator structure includes:

[0163] Step S201: determining a third corresponding relationship between the voltage and temperature of the resonant structure according to a first voltage temperature coefficient of the thin film acoustic wave resonant structure; wherein the first voltage temperature coefficient is related to the piezoelectric material of the thin film bulk acoustic wave resonant structure.

[0164] The piezoelectric materials of the thin film bulk acoustic wave resonator structure are different, and they have different frequency drift data under different DC bias conditions and different temperature conditions. According to the characteristics of the piezoelectric material, the first voltage temperature coefficient of the thin film acoustic wave resonator structure can be determined according to the frequency drift data under different DC bias conditions and different temperature conditions.

[0165] In some embodiments, in the above step S201, determining the third corresponding relationship between the voltage and temperature of the resonant structure according to the first voltage temperature coefficient of the thin film acoustic wave resonant structure includes:

[0166] Step S301: Determine a first voltage temperature coefficient according to the thermal expansion coefficient of the piezoelectric material in the thickness direction, the elastic constant of the piezoelectric material, the piezoelectric strain constant of the piezoelectric material, the dielectric constant of the piezoelectric material, the piezoelectric constant of the piezoelectric material, the electrostriction coefficient of the piezoelectric material and the nonlinear variation coefficient of the stiffness of the piezoelectric material.

[0167] Step S302: determining a third corresponding relationship between the voltage of the resonant structure and the temperature according to the first voltage temperature coefficient.

[0168] When the DC bias changes, the elastic constant and thickness of the piezoelectric material change; when the temperature changes, the thickness of the piezoelectric material changes, and then the frequency drift under different DC biases, the correspondence between the frequency drift at different temperatures and the elastic constant and thickness of the piezoelectric material can be determined based on the thermal expansion coefficient in the thickness direction of the piezoelectric material, the elastic constant of the piezoelectric material, the piezoelectric strain constant of the piezoelectric material, the dielectric constant of the piezoelectric material, the piezoelectric constant of the piezoelectric material, the electrostriction coefficient of the piezoelectric material and the nonlinear change coefficient of the stiffness of the piezoelectric material, and then the first voltage temperature coefficient can be determined.

[0169] In other embodiments, the frequency drift data of the thin film bulk acoustic wave resonator structure at different temperatures (for example, -40°C to 150°C) and the frequency drift data of the thin film bulk acoustic wave resonator structure under different DC bias voltages can be tested; and then a database of DC bias voltages and temperatures of different thin film bulk acoustic wave resonator structures can be established to obtain the first voltage temperature coefficient of each thin film bulk acoustic wave resonator structure.

[0170] In some embodiments, the resistance value of the thermistor at different temperatures is tested, and then a database of the second voltage division and temperature of different thermistors is established to obtain the second voltage temperature coefficient of each FBAR structure.

[0171] In some embodiments, in the above step S103, selecting a thermistor according to the third corresponding relationship and the fourth corresponding relationship, and determining a DC voltage source, includes:

[0172] Step S401: selecting a thermistor according to the third corresponding relationship and the fourth corresponding relationship;

[0173] Step S402: determining the output voltage of the DC voltage source according to the resistance voltage corresponding to the selected thermistor and the resonator voltage.

[0174] By determining the third corresponding relationship between the resonator voltage and the temperature and the fourth corresponding relationship between the resistance voltage of the thermistor and the temperature, it can be determined that the thermistor when the sum of the change value of the resonator voltage and the change value of the resistance voltage is equal to or approximately equal to zero under the same temperature change is the thermistor that matches the thin film bulk acoustic wave resonance structure.

[0175] According to the third corresponding relationship between the resonator voltage and the temperature, and the fourth corresponding relationship between the resistance voltage of the thermistor matched with the film bulk acoustic wave resonator structure and the temperature, the output voltage of the constant voltage source is determined. Exemplarily, the sum of the resonator voltage and the resistance voltage can be determined as the output voltage of the DC voltage source (e.g., the constant voltage source). When the ambient temperature increases (or decreases), the resistance voltage of the thermistor decreases (or increases), and the resonator voltage of the film bulk acoustic wave resonator structure increases (or decreases). The increase (or decrease) in the resonator voltage can offset the frequency shift caused by the increase (or decrease) in the ambient temperature.

[0176] A person skilled in the art can understand that all or part of the steps of implementing the above method embodiment can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the aforementioned storage medium includes: mobile storage devices, read-only memories (ROM), magnetic disks or optical disks, etc., various media that can store program codes.

[0177] Alternatively, if the above-mentioned integrated unit of the present application is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application can be essentially or partly embodied in the form of a software product that contributes to the relevant technology. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0178] The various embodiments / implementations provided in this application can be combined with each other without causing any contradiction. The above description is only a preferred embodiment of this application and is not intended to limit this application. For those skilled in the art, this application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A resonator device, characterized in that include: Film bulk acoustic wave resonator structure, thermistor and DC voltage source; Two ends of the film bulk acoustic wave resonator structure are respectively connected to a radio frequency input end and a radio frequency output end of a radio frequency circuit; After being connected in series with the DC voltage source, the thermistor is connected in parallel to both ends of the thin film bulk acoustic wave resonator structure; the thin film bulk acoustic wave resonator structure, the thermistor and the DC voltage source form a DC circuit.

2. The resonator device according to claim 1, characterized in that The DC voltage source has a preset output voltage; the thin film bulk acoustic wave resonance structure has a first partial voltage; the thermistor has a second partial voltage; and the first partial voltage has a first corresponding relationship with the temperature.

3. The resonator device according to claim 2, characterized in that The first corresponding relationship includes: The first divided voltage is determined according to the product of a first voltage temperature coefficient of the thin film bulk acoustic wave resonator structure and a temperature variation.

4. The resonator device according to claim 3, characterized in that The first voltage temperature coefficient is related to the piezoelectric material of the thin film bulk acoustic wave resonator structure.

5. The resonator device according to claim 4, characterized in that The first voltage temperature coefficient is determined by the following formula: Among them, A is the first voltage temperature coefficient; α is the thermal expansion coefficient of the piezoelectric material in the thickness direction; c0 is the elastic constant of the piezoelectric material; d0 is the piezoelectric strain constant of the piezoelectric material; ε0 is the dielectric constant of the piezoelectric material; h0 is the piezoelectric stiffness constant of the piezoelectric material; N is the electrostrictive coefficient of the piezoelectric material; R is the nonlinear change coefficient of the stiffness of the piezoelectric material.

6. The resonator device according to claim 2, characterized in that The second divided voltage has a second corresponding relationship with temperature, and the preset output voltage is determined by the first divided voltage and the second divided voltage.

7. The resonator device according to claim 6, characterized in that The second corresponding relationship includes: the second divided voltage is determined according to the product of the second voltage temperature coefficient of the thermistor and the temperature change.

8. The resonator device according to any one of claims 1 to 7, characterized in that: It also includes: a first capacitor and a second capacitor; after the thermistor is connected in series with the DC voltage source, the nodes connected to the thin film bulk acoustic wave resonance structure are the first node and the second node; A first end of the first capacitor is connected to the RF input end, and a second end of the first capacitor is connected to a first end of the thin film bulk acoustic wave resonator structure through the first node; The first end of the second capacitor is connected to the second end of the thin film bulk acoustic wave resonator structure through the second node, and the second end of the second capacitor is connected to the radio frequency output end.

9. The resonator device according to claim 8, characterized in that The first capacitor and / or the second capacitor is located in a cavity between the thin film bulk acoustic wave resonator structure and the substrate.

10. The resonator device according to any one of claims 1 to 7, characterized in that: The nodes of the thermistor and the DC voltage source string connected in series and connected to the thin film bulk acoustic wave resonance structure are a first node and a second node; The resonator device further comprises a first inductor and a second inductor, wherein the first inductor and the second inductor are used to block the radio frequency signal from flowing out to the DC circuit; The thermistor and the DC voltage source connected in series are respectively connected to the first node via the first inductor and connected to the second node via the second inductor.

11. The resonator device according to claim 10, characterized in that The first inductor and / or the second inductor is located in a cavity between the thin film bulk acoustic wave resonator structure and the substrate.

12. The resonator device according to any one of claims 1 to 7, characterized in that: After the thermistor is connected in series with the DC voltage source, it is connected in parallel to two ends of the thin film bulk acoustic wave resonator structure to form a first node and a second node in the radio frequency circuit; The thermistor includes a first resistor and a second resistor; Two ends of the DC voltage are respectively connected to the first node through the first resistor, and connected to the second node through the second resistor.

13. A filter, characterized in that: include: A film bulk acoustic wave resonator unit, a thermistor and a DC voltage source; The film bulk acoustic wave resonance unit includes a film bulk acoustic wave resonance structure or a plurality of cascaded film bulk acoustic wave resonance structures; The signal input end and the signal output end of the film bulk acoustic wave resonator unit are respectively connected to the radio frequency input end and the radio frequency output end of the radio frequency circuit; the thermistor is connected in series with the DC voltage source and then connected in parallel with the film bulk acoustic wave resonator unit; Wherein, the thin film bulk acoustic wave resonator unit, the thermistor unit and the DC voltage source form a DC circuit; Alternatively, the filter comprises a resonator device as claimed in any one of claims 1 to 12.

14. A method for preparing a resonator device, characterized in that: include: determining a third corresponding relationship between the resonator voltage and the temperature according to the thin film bulk acoustic wave resonance structure; determining a fourth correspondence between a resistance voltage and a temperature of at least one thermistor; Selecting the thermistor according to the third corresponding relationship and the fourth corresponding relationship, and determining a DC voltage source; Among them, the first end of the thin film bulk acoustic wave resonance structure is connected to the RF input end, and the second end is connected to the RF output end; the RF input end, the thin film bulk acoustic wave resonance structure and the RF output end form an AC signal path; the first end of the thermistor is connected to the RF input end or the RF output end, and the second end is connected to the DC voltage source; the thin film bulk acoustic wave resonance structure, the thermistor and the DC voltage source form a DC circuit.

15. The preparation method according to claim 14, characterized in that: The determining a third corresponding relationship between the voltage and temperature of the resonant structure according to the thin film bulk acoustic wave resonator structure includes: Determining the third corresponding relationship between the voltage and temperature of the resonant structure according to the first voltage temperature coefficient of the thin film acoustic wave resonant structure; The first voltage temperature coefficient is related to the piezoelectric material of the thin film bulk acoustic wave resonance structure.

16. The preparation method according to claim 15, characterized in that: The determining the third corresponding relationship between the voltage and temperature of the resonant structure according to the first voltage temperature coefficient of the thin film acoustic wave resonant structure comprises: determining the first voltage temperature coefficient according to the thermal expansion coefficient in the thickness direction of the piezoelectric material, the elastic constant of the piezoelectric material, the piezoelectric strain constant of the piezoelectric material, the dielectric constant of the piezoelectric material, the piezoelectric constant of the piezoelectric material, the electrostriction coefficient of the piezoelectric material and the nonlinear variation coefficient of the stiffness of the piezoelectric material; The third corresponding relationship between the voltage of the resonant structure and the temperature is determined according to the first voltage temperature coefficient.

17. The preparation method according to claim 14, characterized in that: The step of selecting the thermistor according to the third corresponding relationship and the fourth corresponding relationship and determining a DC voltage source comprises: Selecting the thermistor according to the third corresponding relationship and the fourth corresponding relationship; The output voltage of the DC voltage source is determined according to the resistance voltage corresponding to the selected thermistor and the resonator voltage.

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