Multi-physics-field coupling high-Q-value magnetoacoustic resonator

Abstract

The invention, which belongs to the microwave communication field, discloses a multi-physics-field coupling high-Q-value magnetoacoustic resonator comprising a YIG film, a GGG film substrate, a grounding electrode and a microstrip line. The YIG film generates ferromagnetic resonance under the action of an external magnetic field, the magnetoelastic effect of a YIG material is coupled with a standing wave thickness acoustic mode in a YIG-GGG heterostructure, and the mode combines the broadband adjustable characteristic of a magnetic resonance mode and the high-quality factor (Q value) characteristic of an acoustic resonance mode, so that the magnetoacoustic resonator simultaneously meets the broadband adjustable characteristic and the high-Q value characteristic; in the process, the YIG film plays a role of a transducer, the mode of the heterogeneous film and the microstrip line is adopted, an air gap of a magnetic circuit can be reduced, the size of a bias magnetic circuit is greatly reduced, and therefore the resonator is miniaturized.

Description

Technical Field

[0001] The present invention relates to the field of microwave communication technologies, and particularly to a multi-physical-field-coupled high-Q magnetoacoustic resonator. Background Art

[0002] In the fields of communication and high-end microwave instruments, in order to increase the detection range, reduce the demodulation error rate of signals, improve the sensitivity of instruments, etc., a low-phase-noise frequency source is often required. In order to meet the requirements of different frequency bands, the frequency of the frequency source also needs to be adjustable. Therefore, existing frequency sources often adopt YIG oscillators (YTOs) based on YIG resonators. Its basic principle is based on the ferromagnetic resonance effect, and it has advantages such as a wide tuning frequency band, good linearity, and low phase noise.

[0003] The principle and use of a resonator are both unified and contradictory. It can be applied to an oscillator to output a specific radio frequency signal, and can also be applied to a filter to filter out a specific frequency signal.

[0004] The phase noise of an oscillator is related to the Q value. According to the Leeson formula, the higher the Q value of the resonator, the lower the phase noise. In a YIG resonator, the Q value of the resonator is inversely proportional to the coupling strength. When the coupling strength increases, the Q value decreases, the tuning frequency band becomes wider, the phase noise increases, the linearity decreases, and the static magnetic mode is more likely to appear; vice versa.

[0005] Traditional YIG resonators mainly generate coupling between the YIG sphere and the circuit by adding a coupling loop around the YIG sphere and connecting the coupling loop to the circuit. The coupling strength is regulated by controlling the global ratio or the distance between the coupling loop and the YIG sphere. The larger the global ratio or the farther the distance between the coupling loop and the YIG sphere, the smaller the coupling strength; vice versa.

[0006] To meet the technical specifications, experienced debugging personnel are required to adjust the global structure to adapt to the circuit system. In addition, the YIG sphere is affected by the material's anisotropic field and the change of the anisotropic field with temperature. To eliminate the influence of environmental temperature, etc., it is necessary to determine the temperature stable axis of each YIG sphere and make it form a specific angle with the external magnetic field. This process requires preliminary orientation and heating orientation on the device, which greatly increases the difficulty and complexity of debugging.

[0007] A thin-film bulk acoustic resonator (FBAR) makes the thin film vibrate to emit acoustic waves through the piezoelectric effect of the piezoelectric thin film material. The acoustic waves are reflected at the thin film / air interface to form a standing wave, which is amplified only at a specific frequency (resonance frequency). FBARs are small in size, have a high Q value, low insertion loss, and are easy to integrate, but their tuning frequency range is relatively narrow and their operating frequency is relatively low compared to magnetic resonators.

[0008] That is, with the gradual increase in electronic devices, the electromagnetic environment faced by electronic instrument devices will become increasingly complex, and higher requirements are imposed on the phase noise of radio frequency devices. Resonators with high Q values, such as optoelectronic resonators and dielectric resonators, are large in volume and poor in temperature stability. Solid-state acoustic resonators have high Q values and small volumes, but their frequencies are not tunable.

[0009] The traditional low-frequency band is fully occupied. To obtain new communication frequency bands and more load information, communication technologies are developing towards high-frequency bands. The traditional YIG resonator is one of the few resonators that can meet the requirements of high-frequency broadband tunability. Although its Q value is the highest among such resonators, it is difficult to further improve the Q value of the traditional YIG resonator. Moreover, currently, the traditional YIG resonator adopts a globe structure and is mainly completed through traditional machining and manual debugging, which also reduces product consistency, increases product production time, makes it difficult to integrate with MMICs, etc., and the product has a large volume and high power consumption. Among them, MMIC refers to monolithic microwave integrated circuits, which is a technology that integrates microwave circuits on a single semiconductor substrate. It manufactures passive and active components on the same substrate through semiconductor processes to form a complete microwave circuit. It is widely used in radio frequency and microwave communication systems. Here, it mainly shows that the product cannot be integrated into the MMIC system, and the inability to integrate means the inability to miniaturize. Summary of the Invention

[0010] The object of the present invention is to provide a multi-physical-field-coupled high-Q magneto-acoustic resonator to solve the above problems.

[0011] To achieve the above object, the technical solution adopted by the present invention is as follows: A multi-physical-field-coupled high-Q magneto-acoustic resonator includes a YIG thin film, a GGG thin film substrate, a ground electrode, and a microstrip line. Among them, the microstrip line is disposed on the YIG thin film, the YIG thin film is disposed on the GGG thin film substrate, and the ground electrode is disposed under the GGG thin film substrate.

[0012] As a preferred technical solution, the microstrip line is a single long strip for the input and output of RF signals, and the microstrip line is disposed in the exact middle of the upper surface of the YIG thin film.

[0013] As a preferred technical solution, the YIG thin film is rectangular or square or circular, with an area of 1*1 mm 2 or 1*2 mm 2 .

[0014] The thickness of the YIG film is determined according to the required standing-wave acoustic thickness mode. Specifically, the standing-wave acoustic thickness mode refers to the condition for the formation of standing waves of sound waves in the substrate, which is usually related to the substrate thickness d and the sound wave wavelength λ, where d = n·λ / 2, and n is a positive integer (1, 2, 3...), representing the mode number of the standing wave. Usually, n = 1 is used for the fundamental mode. Therefore, this standing-wave acoustic mode thickness is determined according to the specific sound wave wavelength; The saturation magnetization of the YIG film is 1750 Gs. Currently, the saturation magnetization of single-crystal films in China is 1750 Gs, which is a theoretical value and refers to undoped YIG films, suitable for high-frequency and low-loss applications.

[0015] As a preferred technical solution, the microstrip line or circuit on the surface of the YIG film is fabricated by a coating and etching process.

[0016] As a preferred technical solution, the YIG film is prepared by liquid-phase epitaxy technology, or radio-frequency magnetron sputtering method, or pulsed laser deposition method.

[0017] As a preferred technical solution, the GGG film substrate is rectangular, square or circular, with an area of 1*1 mm 2 or 1*2 mm 2 , and the thickness of the GGG substrate is determined according to the required standing-wave acoustic thickness mode. As mentioned before: the standing-wave acoustic thickness mode refers to the condition for the formation of standing waves of sound waves in the substrate, which is usually related to the substrate thickness d and the sound wave wavelength λ, where d = n·λ / 2, and n is a positive integer (1, 2, 3...), representing the mode number of the standing wave. Usually, n = 1 is used for the fundamental mode. Therefore, this standing-wave acoustic mode thickness is determined according to the specific sound wave wavelength, and a value can be determined based on the wavelength.

[0018] As a preferred technical solution, the planar area of the GGG film substrate is greater than or equal to that of the YIG film.

[0019] As a preferred technical solution, the grounding electrode is a metal sputtered on the back of the GGG film substrate, and the grounding electrode is bonded to the ground of the magnetic circuit cavity through a conductive adhesive.

[0020] As a preferred technical solution, to satisfy the formation of the standing-wave acoustic thickness mode in the YIG-GGG heterostructure, both sides of the YIG-GGG heterostructure need to be polished to ensure the surface roughness and the parallelism among the surface of the YIG film, the surface of the GGG substrate, and the interface between the YIG film and the GGG substrate. Generally, a chemical-mechanical polishing technology or a combined polishing technology of mechanical rough polishing - plasma fine polishing is adopted.

[0021] As a preferred technical solution, the ground electrode on the surface of YIG microstrip line and the bottom surface of GGG generally uses gold or other metals that can use coating process and have good conductivity; a transition layer can be added between the microstrip line and the surface of YIG and between the ground electrode and the surface of GGG to improve the bonding force.

[0022] Specifically: If the adhesion test shows that the bonding force is lower than 10-20 MPa or in the scratch test, the critical load is lower than 10 mN, then a transition layer needs to be added. The transition layer is selected to be lattice-matched with YIG and GGG and have a similar coefficient of thermal expansion, such as MgO, Al2O3, TiO2, etc. The thickness of the transition layer is usually between a few nanometers and a few hundred nanometers. Too thick may introduce new stresses, and too thin may not have enough effect. The actual thickness needs to be verified by experiments, and the shape and size are the same as those of YIG and GGG.

[0023] The multi-physical-field-coupled magnetoacoustic resonator or magnetoacoustic coupled resonator of the present invention includes a yttrium iron garnet (YIG) thin film, a gadolinium gallium garnet (GGG) thin film substrate, a ground electrode, and a microstrip line; the microstrip line is attached to the YIG thin film, and the input and output share the same microstrip line, which plays a coupling role and is an improvement over the traditional coupling loop. The YIG thin film generates ferromagnetic resonance under the action of an external magnetic field, and is coupled with the standing-wave thickness acoustic mode in the YIG-GGG heterostructure through the magnetoelastic effect of the YIG material. This mode combines the broadband tunable characteristics of the magnetic resonance mode and the high quality factor (Q value) characteristics of the acoustic resonance mode, enabling the magnetoacoustic resonator to simultaneously satisfy the broadband tunable and high Q value characteristics. In this process, the YIG thin film acts as a transducer. The present invention adopts the method of heterogeneous thin film plus microstrip line, which can reduce the magnetic circuit air gap and significantly reduce the volume of the bias magnetic circuit, thereby miniaturizing the resonator.

[0024] Therefore, the present invention uses a multi-physical-field-coupled magnetoacoustic resonator, which can improve the selectivity of the YIG filter and reduce the phase noise of the YIG oscillator; at the same time, compared with the YIG resonator with a traditional global coupling structure, the production efficiency and consistency are improved. In addition, by adopting a heterogeneous thin film structure, the magnetic circuit air gap can be reduced, and the volume and power consumption of the YIG filter and the YIG oscillator can be significantly reduced.

[0025] Compared with the prior art such as CN107919517A, there are essential differences. CN107919517A is based on the YIG ferromagnetic resonance mode, while the present invention is magnetoacoustic coupling, similar to an acoustic wave resonator, where acoustic waves are reflected at the thin film / air interface to form standing waves and are only amplified at specific frequencies. Moreover, the magnetoacoustic resonator of the present invention can be applied to oscillators and YIG band-stop filters.

[0026] Compared with the prior art, the advantages of the present invention are as follows: (1) Improving the Q value of the resonator is beneficial to enhancing the Q values of filters and oscillators. For filters, it improves selectivity, and for oscillators, it reduces phase noise. (2) Compared with traditional YIG resonators that mainly adopt a global coupling structure and rely on experienced technicians for debugging, the resonator structure of the present invention improves the production efficiency and consistency of YIG resonators. Among them, since the present invention adopts a non-global structure and only sputters transmission lines, it can significantly improve production efficiency and consistency, and the production efficiency can be increased by about one time. (3) Reducing the magnetic circuit air gap can reduce the volume and power consumption of YIG devices. With the reduction of the coil of the same volume, the volume of the present invention can be reduced by about 1 / 5. Description of the Drawings

[0027] Figure 1 It is the structure diagram of the magneto-acoustic resonator based on the YIG-GGG heterostructure of Embodiment 1 of the present invention; Figure 2 is Figure 1 Schematic diagram of the principle of the magneto-acoustic resonator; Figure 3 is for manufacturing Figure 1 Flowchart of the magneto-acoustic resonator; Figure 4 is based on Figure 1 Schematic diagram of the band-stop filter of the magneto-acoustic resonator; Figure 5 is based on Figure 1 Schematic diagram of the oscillator of the magneto-acoustic resonator; In the figure: 101, microstrip line; 102, YIG thin film; 103, GGG thin film substrate; 104, ground electrode; 105, externally applied bias magnetic field; 401, magneto-acoustic resonator; 402, vector network analyzer; 403, input interface; 404, output interface; 501, transistor bias negative voltage; 502, bipolar junction transistor; 503, transistor collector bias voltage; 504, matching circuit; 505, DC-blocking capacitor; 506, amplifier; 507, amplifier supply voltage; 508, oscillator output interface; 509, resonator pre-capacitor. Specific Embodiments

[0028] To make the purpose, technical solutions, etc. of the embodiments of the present invention clearer, the following will comprehensively describe the technologies in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Other embodiments using similar principles or alternative components to achieve the same purpose are within the protection scope of the present invention. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0029] Example 1: This example presents a magnetoacoustic resonator based on multi - physical - field coupling. As Figure 1 shown, it includes a microstrip line 101, a YIG thin film 102, a GGG thin - film substrate 103, a ground electrode 104, and an externally applied bias magnetic field 105. Among them, the externally applied bias magnetic field 105 is part of the magnetoacoustic resonator. Additionally, whether a transition layer is needed is determined according to the actual bonding force of the used microstrip line, and the transition metal layer is not shown in the figure. Among them, the microstrip line 101 is located at the middle position on the upper surface of the YIG thin film 102. The impedance of the microstrip line 101 can be changed by changing the dielectric material and its thickness, the thickness and width of the microstrip line, so as to match with other circuits and reduce the reflected standing wave. For example, widening the microstrip line reduces the impedance, and vice versa; thickening the microstrip line increases the impedance, and vice versa; increasing the thickness of the dielectric material increases the impedance, and vice versa. The microstrip line 101 generally selects an impedance of 50Ω. In this example, the average dielectric constant of the YIG thin film and the GGG thin - film substrate is taken as 15. When calculating, the YIG / GGG heterostructure is 400μm thick, the microstrip line is 50μm thick, 0.2mm wide, and the impedance is 50Ω at a frequency of 1GHz. In this example, the length and width of the YIG thin film 102 and the GGG thin - film substrate 103 are selected as a square of 1*1mm 2 . The thicknesses of the YIG and GGG are related to the operating frequency and coupling strength of the magnetoacoustic resonator. In this example, the YIG thin film can be selected to be 5 - 20μm, and the GGG thin - film substrate can be selected to be between 380 - 395μm, and the overall thickness of the two is 400μm. The externally applied bias magnetic field 105 is adjustable. Generally, it is composed of a coil and a permalloy cavity. The magnitude of the external magnetic field is adjusted by adjusting the current in the coil. The permalloy cavity can reduce the internal loss of the magnetic circuit and make the YIG sample in a uniform magnetic field. Specifically, reference can be made to the patent CN210223700U, a high - speed YIG bulk band - stop filter.

[0030] The schematic diagram of the principle of the magnetoacoustic resonator in this example is as Figure 2As shown in the figure: Under the action of the externally applied bias magnetic field 105, the magnetic moment m of the YIG thin film 102 precesses around the externally applied bias magnetic field 105 at a certain frequency, generating a circularly polarized high-frequency magnetic field around it, and its frequency is related to the precession frequency of the magnetic moment m. At this time, if an RF signal is input to the microstrip line 101, when a certain frequency in the RF signal is the same as the precession frequency of the magnetic moment m, ferromagnetic resonance occurs, and the magnetic vibration mode generated by the precession generates an acoustic vibration mode through the magnetoelastic effect of the YIG thin film 102. Since the sound velocity is almost the same in the YIG thin film 102 and the GGG thin film substrate 103, this acoustic mode will propagate throughout the YIG-GGG heterostructure. When the acoustic mode satisfies the reflection condition in the YIG-GGG heterostructure to form a standing wave, resonance is formed.

[0031] Figure 3 Flow chart for fabricating the above magnetoacoustic resonator: The first step is to polish the GGG thin film substrate by mechanical chemical polishing technology or ion beam polishing technology: This step is mainly to ensure that the YIG-GGG interface is flat and smooth. If the surface of the GGG thin film substrate already meets the requirements (generally, polishing is required when the surface roughness Ra > 1nm), polishing is not necessary, and the surface roughness can be characterized by SEM or AFM; The second step is to grow the YIG thin film by liquid phase epitaxy: In this embodiment, a 1750 Gs pure YIG thin film is grown. To ensure the required thickness and uniformity of the YIG thin film and to ensure that it will not crack due to stress during the growth process, it is necessary to control the growth formula, solution concentration, growth rate, growth temperature, crucible rotation speed, and substrate rotation speed of the YIG thin film. This belongs to the prior art. For example, it can be referred to: Wang Ang. Research on the Equipment and Growth of YIG Single Crystal by Liquid Phase Epitaxy [D]. Shanghai Institute of Technology, 2020. He Shuixiao. Growth Process and Wire Forming Technology of YIG Ferrite Single Crystal / Thin Film [J]. Southwest Institute of Applied Magnetics, China. etc.; The third step is to polish the YIG-GGG sample by mechanical chemical polishing technology or a combination of mechanical rough grinding-polishing and ion beam fine grinding-polishing technology: This step is mainly to ensure that the upper surface of the YIG thin film, the lower surface of the GGG thin film substrate, and the upper surface of the YIG thin film, the interface between the YIG thin film and the GGG thin film substrate, and the lower surface of the GGG thin film substrate are flat and smooth and parallel to each other. The surface roughness can be characterized by SEM or AFM, and the parallelism between the three surfaces can be measured by optical interference method, profilometer, and laser measurement comparison method. Since the magnetoacoustic resonator has certain requirements for the thickness of the YIG thin film and the GGG thin film substrate, for the combined grinding and polishing method of mechanical rough grinding-polishing and ion beam fine grinding-polishing, it is necessary to first pre-grind and polish the YIG thin film and the GGG thin film substrate to near the required thickness, and then use ion beam fine grinding-polishing to reach the required thickness. In this embodiment, only one layer of YIG thin film and one layer of GGG thin film substrate are required, so it is necessary to remove one of the YIG thin films on both sides of the GGG thin film substrate in advance; Step 4: Deposit a transition layer: This step is mainly to enhance the bonding strength between the microstrip line and the YIG film, and between the ground electrode and the GGG film substrate. Generally, magnetron sputtering technology can be used to deposit the transition layer. The bonding strength depends on the material properties of the microstrip line, YIG film, GGG film substrate, and ground electrode. If the bonding strength meets the requirements, this step may not be necessary; Step 5: Sputter the metal layer. This step is mainly to fabricate the ground electrode and lay the foundation for fabricating the microstrip line. In this embodiment, metal gold is used as the material for the microstrip line and the ground electrode, so the metal layer can be sputtered simultaneously. In this embodiment, the thickness of the metal layer on the surface of the YIG film is 50 μm according to the requirements of the microstrip line thickness. For cases where different materials are used for the ground electrode and the microstrip line, separate coating is required; Step 6: Etch the microstrip line. This step mainly etches the microstrip line through the metal layer on the surface of the YIG to form the input and output channels for the RF signal, playing the role of the coupling loop in the traditional YIG resonator. The etching of the microstrip line is mainly completed through steps such as cleaning, surface pretreatment, spin-coating photoresist, pre-baking, exposure, post-baking, development, hardening, detection, etching, and removing the photoresist. According to this embodiment, the width of the microstrip line is required to be 0.2 mm, so a mask plate needs to be fabricated according to the requirements; Step 7: Cutting. This step is mainly to cut the YIG-GGG sample with the surface circuit already fabricated into individual magneto-acoustic resonators. Generally, existing laser cutting and wire cutting methods can be used.

[0032] It should be noted that the implementation steps of the magneto-acoustic resonator of the present invention may not be carried out according to the above implementation steps, as long as the purpose of fabricating a qualified magneto-acoustic resonator is achieved. For example, the cutting step can be placed after any step after the step of growing the YIG film.

[0033] Embodiment 2 A band-stop filter based on the magneto-acoustic resonator of the above Embodiment 1, the schematic structural diagram is as Figure 4 shown; it includes the magneto-acoustic resonator 401 of Embodiment 1, an externally applied bias magnetic field 105, a vector network analyzer 402, an input interface 403, and an output interface 404. Among them, the magneto-acoustic resonator 401 and the externally applied bias magnetic field 105 form a basic band-stop filter. The 101 microstrip line is connected to the input interface 403 and the output interface 404 through a coaxial cable or the like.

[0034] Embodiment 3 An oscillator based on the magneto-acoustic resonator of Embodiment 1, the schematic structural diagram is as Figure 5As shown in the figure, it includes a magnetoacoustic resonator 401 and an externally applied bias magnetic field 105. One end of the magnetoacoustic resonator 401 is sequentially connected to a bipolar junction transistor 502, a transistor collector bias voltage 503, a matching circuit 504, a DC blocking capacitor 505, an amplifier 506, an amplifier supply voltage 507, and an oscillator output interface 508. The other end is connected to a transistor bias negative voltage 501 and a resonator pre-capacitor 509. Among them, the transistor bias negative voltage 501 and the transistor collector bias voltage 503 mainly make the bipolar junction transistor 502 located at a suitable static operating point to provide negative resistance compensation for the magnetoacoustic resonator 401 and generate resonance. For different frequency bands, the bipolar junction transistor 502 can also be replaced by a heterojunction bipolar transistor or a field effect transistor; the matching circuit 504 is generally applicable to broadband tuning situations to make the standing waves in the low-frequency band and high-frequency band appropriate. The DC blocking capacitor 505 prevents DC signals from entering the amplifier. The amplifier 506 mainly increases the output power of the RF signal. The resonator pre-capacitor 509 has two main functions: one is to filter the DC output by the negative voltage power supply, and the other is to form a feedback loop. Generally, other circuits except the magnetoacoustic resonator can be integrated on an alumina ceramic substrate. The ceramic substrate is close to the magnetoacoustic resonator and is connected by gold wires or gold strips.

[0035] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "middle", "upper", "lower", "left", "right", "vertical", "horizontal", etc. is the relative positional relationship in the shown drawings. It is only for the convenience of describing the embodiments of the present invention and does not indicate or imply that the device or element referred to must have a specific orientation or position. Instead, it is the orientation or positional relationship commonly understood by those skilled in the art and cannot be used as a basis for limiting the protection scope of the present invention.

[0036] The above are only the embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-physical-field-coupled high-Q magnetoacoustic resonator, characterized in that, It includes a YIG thin film, a GGG thin film substrate, a ground electrode, and a microstrip line. Among them, the microstrip line is disposed on the YIG thin film, the YIG thin film is disposed on the GGG thin film substrate, and the ground electrode is disposed under the GGG thin film substrate.

2. The multi-physical-field-coupled high-Q magnetoacoustic resonator according to claim 1, characterized in that The microstrip line is a single long strip for the input and output of RF signals, and the microstrip line is disposed exactly in the middle of the upper surface of the YIG thin film.

3. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, characterized in that, The YIG thin film is rectangular, square or circular, with an area of 1*1 mm 2 or 1*2 mm 2 . The thickness of the YIG thin film is determined according to the required standing wave acoustic thickness mode; the saturation magnetization intensity of the YIG thin film is 1750 Gs.

4. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, characterized in that The microstrip line or circuit on the surface of the YIG thin film is fabricated by a coating and etching process.

5. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, wherein The YIG thin film is prepared by liquid phase epitaxy technology, or radio frequency magnetron sputtering method, or pulsed laser deposition method.

6. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, characterized in that The GGG thin film substrate is rectangular, square or circular, with an area of 1*1 mm 2 or 1*2 mm 2 , and the thickness of the GGG substrate is determined according to the required standing wave acoustic thickness mode.

7. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, characterized in that The planar area of the GGG thin film substrate is greater than or equal to that of the YIG thin film.

8. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, characterized in that The ground electrode is a metal sputtered on the back of the GGG thin film substrate, and the ground electrode is bonded to the ground of the magnetic circuit cavity through a conductive adhesive.

9. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, characterized in that, To meet the formation of the standing wave acoustic thickness mode in the YIG-GGG heterostructure, both sides of the YIG-GGG heterostructure need to be polished to ensure the surface roughness and the parallelism among the surface of the YIG thin film, the surface of the GGG substrate, and the interface between the YIG thin film and the GGG substrate. Generally, a chemical-mechanical polishing technology or a combined polishing technology of mechanical rough polishing - plasma fine polishing is adopted.

10. The magnetoacoustic resonator with multi-physical field coupling according to claim 1, characterized in that Generally, gold or other metals that can use the coating process and have good conductivity are used for the microstrip line on the YIG surface and the ground electrode on the bottom surface of the GGG. A transition layer can be added between the microstrip line and the YIG surface and between the ground electrode and the GGG surface to improve the bonding force.

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