Bandpass filter device

Abstract

The application provides a band-pass filter device, comprising: a spin waveguide material having a magnetization direction in response to an electric signal, for exciting a spin wave signal based on the electric signal, and exciting a spin wave signal that has passed band-pass filtering based on a surface acoustic wave signal; a receiving antenna located on the spin waveguide material, for receiving the electric signal; a piezoelectric transducer located on the spin waveguide material, for converting the spin wave signal into a surface acoustic wave signal that has passed band-pass filtering based on a changed magnetization direction; and a transmitting antenna located on the spin waveguide material, for outputting the spin wave signal that has passed band-pass filtering after being converted into an electric signal that has passed band-pass filtering. The application can achieve a band-pass filtering effect with a wider applicable frequency band range and a higher filtering frequency, and has the advantages of low power consumption and easy miniaturization.

Description

Technical Field

[0001] This invention relates to the field of radio frequency filtering technology, and more specifically, to a bandpass filter. Background Technology

[0002] Surface acoustic wave (SAW) filters are widely used in mobile phones. They typically use piezoelectric materials as the substrate and interdigital transducers at both ends as the receiving and transmitting ends, respectively. When an electrical signal is input through the transmitting transducer, the piezoelectric effect of the material converts the signal into surface acoustic waves propagating on the substrate surface. These waves are then converted back into electrical signals at the receiving transducer, thus filtering the input signal. The interdigital transducer is a crucial component in realizing the function of the SAW filter, and its main parameters include finger length, finger width, finger spacing, and the number of interdigit pairs. Achieving the desired filtering characteristics often requires careful design of the structure and dimensions of the interdigital transducers at both the receiving and transmitting ends. Furthermore, interdigital transducers are limited by SAW wavelengths; when receiving combined radio frequency signals, they only allow signals of specific frequencies to pass through while blocking other frequencies, resulting in a limited filtering frequency range, making them more suitable for low-frequency bands (often less than 3 GHz). Additionally, the wavelength limitation of SAW restricts further miniaturization of the device. Therefore, with the gradual increase in 5G penetration, there is a need to develop a filter device that has a wider applicable frequency band, higher filtering frequency, better miniaturization, and lower power consumption.

[0003] In recent years, spin waves, as a wave-like form that can be excited by electrical signals or magnetic fields and propagate in ferromagnetic, ferrimagnetic, and antiferromagnetic materials, have been considered an ideal carrier of information in future transmission and computing architectures due to their theoretically no ohmic loss during propagation and their short wavelength and good miniaturization. Meanwhile, the coupling interaction between spin waves and surface acoustic waves (SAWs) has gradually become a research hotspot in academia, but current research focuses more on using SAWs to extend the attenuation length of spin waves, reduce the damping coefficient, and excite non-reciprocal spin waves. However, in the design of filters that use SAWs to excite spin waves, when a spin wave is generated, it absorbs a large amount of energy and dissipates it significantly at the resonant frequency, thus blocking that frequency. This actually implements a band-stop filter rather than a band-pass filter. Summary of the Invention

[0004] The main objective of this invention is to provide a bandpass filter device that achieves a wider applicable frequency band and higher filtering frequency, while also offering advantages such as low power consumption and ease of miniaturization.

[0005] To achieve the above objectives, embodiments of the present invention provide a bandpass filter device, comprising:

[0006] Spin waveguide materials have a magnetization direction that responds to an electrical signal, and are used to excite spin wave signals based on electrical signals and to excite bandpass filtered spin wave signals based on surface acoustic wave signals.

[0007] A receiving antenna located on a spin waveguide material is used to receive electrical signals;

[0008] A piezoelectric transducer located on a spin waveguide material is used to convert a spin wave signal into a bandpass filtered surface acoustic wave signal based on a changing magnetization direction.

[0009] A transmitting antenna located on a spin waveguide material is used to convert a bandpass-filtered spin wave signal into a bandpass-filtered electrical signal for output.

[0010] In one embodiment, it further includes:

[0011] The substrate, on which the spin waveguide material is located.

[0012] In one embodiment, the receiving antenna and the transmitting antenna are arranged symmetrically.

[0013] In one embodiment, both the receiving antenna and the transmitting antenna are coplanar waveguide antennas.

[0014] In one embodiment, the coplanar waveguide antenna includes a central conductor strip and conductor planes located on both sides of the central conductor strip.

[0015] In one embodiment, both the receiving antenna and the transmitting antenna are strip antennas.

[0016] In one embodiment, the strip antenna includes a conductor plane.

[0017] In one embodiment, the spin waveguide material comprises yttrium iron garnet ferrite.

[0018] In one embodiment, the piezoelectric transducer includes a zinc oxide thin film, a piezoelectric single crystal, or a piezoelectric ceramic.

[0019] In one embodiment, the substrate comprises gadolinium gallium garnet.

[0020] The bandpass filtering device of this invention includes a spin waveguide material with a magnetization direction responsive to an electrical signal for exciting a spin wave signal based on the electrical signal, a receiving antenna located on the spin waveguide material for receiving the electrical signal, a piezoelectric transducer located on the spin waveguide material for converting the spin wave signal into a bandpass-filtered surface acoustic wave signal based on a changing magnetization direction, exciting the bandpass-filtered spin wave signal in the spin waveguide material based on the surface acoustic wave signal, and a transmitting antenna located on the spin waveguide material for converting the bandpass-filtered spin wave signal into a bandpass-filtered electrical signal for output. This device can achieve a wider applicable frequency band and a higher filtering frequency bandpass filtering effect, and has the advantages of low power consumption and easy miniaturization. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a front view schematic diagram of the bandpass filter device in an embodiment of the present invention;

[0023] Figure 2 This is a top view schematic diagram of the filter device structure in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the working process of the filtering device in an embodiment of the present invention;

[0025] Figure 4 This is a front view of the structure in this embodiment of the invention, which uses a coplanar waveguide antenna as both a receiving and transmitting antenna.

[0026] Figure 5 This is a top view of the structure in this embodiment of the invention, which uses a coplanar waveguide antenna as both a receiving and transmitting antenna.

[0027] Figure 6 This is a front view of the structure in this embodiment of the invention, which uses a strip antenna as both a receiving and transmitting antenna.

[0028] Figure 7 This is a top view of the structure in this embodiment of the invention, which uses a strip antenna as both a receiving and transmitting antenna.

[0029] Figure 8 This is a schematic diagram of the bandpass filtering function in an embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Those skilled in the art will recognize that embodiments of the present invention can be implemented as a system, apparatus, device, method, or computer program product. Therefore, this disclosure can be specifically implemented in the following forms: entirely hardware, entirely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software.

[0032] Given that current surface acoustic wave (SAW) filters have a fixed filtering frequency range and their size is not easily reduced, this invention provides a bandpass filter based on the coupling interaction of spin waves and SAW. Utilizing spin wave-induced SAW as the basic working mechanism, it combines the advantages of short wavelength and lossless propagation of spin waves with the advantages of fast propagation speed and long relaxation time of SAW to achieve a wider applicable frequency band and higher filtering frequency. It also features a simple antenna structure, low power consumption, and ease of miniaturization. The invention will be described in detail below with reference to the accompanying drawings.

[0033] Figure 1 This is a front view schematic diagram of the bandpass filter device in an embodiment of the present invention. Figure 2 This is a top view schematic diagram of the filter device in an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the workflow of the filtering device in an embodiment of the present invention. Figures 1-3 As shown, the bandpass filter device is a cuboid (the aspect ratio is determined according to actual needs), with dimensions in the nanometer range, including:

[0034] The spin waveguide material 3 has a magnetization direction that responds to an electrical signal and is used to excite a spin wave signal (SW) based on an input electrical signal 1 and to excite a bandpass filtered spin wave signal based on a surface acoustic wave signal (SAW). The spin waveguide material 3 may include yttrium iron garnet ferrite (YIG) or other materials with similar properties.

[0035] The receiving antenna 2, located on the spin waveguide material 3, is used to receive the input electrical signal 1;

[0036] The piezoelectric transducer 4 located on the spin waveguide material 3 is used to convert the spin wave signal into a bandpass filtered surface acoustic wave signal based on the changing magnetization direction; wherein, the piezoelectric transducer 4 may include a zinc oxide (ZnO) thin film, a piezoelectric single crystal or a piezoelectric ceramic.

[0037] The principle behind piezoelectric transducers converting spin wave signals into bandpass filtered surface acoustic wave signals is as follows: When a spin wave excited by an electrical signal propagates in a spin waveguide material, the change in the magnetization direction within the material causes a displacement change in the lattice of the piezoelectric material fabricated on the material surface. When this collective motion reaches a resonant frequency, surface acoustic waves are generated at the interface between the spin waveguide material and the piezoelectric material, thus achieving the spin wave to surface acoustic wave conversion. When different input electrical signals excite spin waves of different frequencies within the spin waveguide material, the change in magnetization direction will also generate different stresses on the piezoelectric material. These stresses will then generate and propagate surface acoustic waves of the corresponding resonant frequency at the interface between the two materials, thereby achieving a filter device with a wider frequency range and higher filtering frequency—that is, a bandpass filter device that achieves an elastic frequency range filtering effect for the input signal.

[0038] The transmitting antenna 5, located on the spin waveguide material 3, is used to convert the bandpass-filtered spin wave signal into a bandpass-filtered output electrical signal 6 before outputting it. The receiving antenna 2 and the transmitting antenna 5 are symmetrically arranged.

[0039] Substrate 7, on which the spin waveguide material is located. The substrate may include gadolinium gallium garnet (GGG). GGG is a dedicated substrate for YIG, and the substrate material can be selected based on the specific spin waveguide material used.

[0040] Figure 4 This is a front view of the structure of the coplanar waveguide antenna used as both the receiving and transmitting antenna in an embodiment of the present invention. Figure 5 This is a top view of the structure in an embodiment of the present invention, using a coplanar waveguide antenna as both the receiving and transmitting antennas. Figures 4-5 As shown, when both the receiving antenna 2 and the transmitting antenna 5 are coplanar waveguide antennas 21, the coplanar waveguide antenna 21 includes a central conductor strip and conductor planes located on both sides of the central conductor strip. The receiving antenna 2 and the transmitting antenna 5 are used symmetrically with the same structure.

[0041] Figure 6 This is a front view of the structure in an embodiment of the present invention, which uses a strip antenna as both a receiving and transmitting antenna. Figure 7 This is a top view of the structure in an embodiment of the present invention, using a strip antenna as both a receiving and transmitting antenna. Figures 6-7 As shown, when both the receiving antenna 2 and the transmitting antenna 5 are strip antennas 22, the strip antenna 22 includes a conductor plane, and the receiving antenna 2 and the transmitting antenna 5 are used symmetrically with the same structure.

[0042] The fabrication processes for bandpass filter devices include magnetron sputtering, molecular beam epitaxy (MBE), ion beam deposition (IBD), physical vapor deposition (CVD), and plasma-enhanced chemical vapor deposition (PECVD). Photolithography methods can include ultraviolet lithography (UVL) and ion beam lithography (EBL). Etching methods can include non-metallic oxide or metal hard masks, reactive ion etching (RIE), ion beam etching (IBE), and chemical mechanical planarization (CMP). It should be noted that the deposition, photolithography, and etching processes are selected from, but not limited to, the above-mentioned types, and can also be a combination of multiple processes, depending on the composition of the substrate material, spin waveguide material, and piezoelectric material, etc.

[0043] The working process of the bandpass filter device in this embodiment of the invention is as follows:

[0044] 1. Conversion between electrical signal and spin wave signal

[0045] like Figures 1-3 As shown, when the receiving antenna receives the input radio frequency electrical signal, the electrical signal excites a spin wave signal in the spin waveguide material, realizing the conversion of electrical signal to spin wave signal.

[0046] 2. Conversion and filtering of spin wave signal to surface acoustic wave signal

[0047] like Figures 1-3 As shown, when the spin wave signal propagates along the surface of the spin waveguide material to the piezoelectric transducer region, the interaction between the spin wave and surface acoustic wave (SAW) causes a change in the magnetization direction within the spin waveguide material, further applying stress to the SAW and thus inducing lattice displacement within the SAW. When the resonant frequency is reached, SAW is induced at the interface between the spin waveguide material and the SAW. This SAW at this frequency achieves the conversion of the spin wave signal to the SAW signal and performs bandpass filtering through the SAW region.

[0048] 3. Conversion of surface acoustic wave signal to spin wave signal

[0049] like Figures 1-3 As shown, after the surface acoustic wave signal propagates through the piezoelectric transducer, it is re-excited to propagate spin waves in the spin waveguide material under the interaction of surface acoustic wave-spin wave coupling, thus realizing the conversion of surface acoustic wave signal to spin wave signal.

[0050] 4. Spin wave signal to electrical signal conversion

[0051] like Figures 1-3 As shown, when the spin wave signal propagates to the transmitting antenna, it is converted into an electrical signal after being filtered by the transmitting antenna and then output, thus realizing the conversion between spin wave signal and electrical signal.

[0052] Figure 8This is a schematic diagram of the bandpass filtering function in an embodiment of the present invention, with the horizontal axis representing frequency and the vertical axis representing transmission throughput. Figure 8 This is for illustrative purposes only and does not involve any specific parameters. Figure 8 As shown, the frequency is at f low and f high The frequencies within the specified range can be filtered using the bandpass filter device of this invention.

[0053] In summary, the bandpass filtering device of this invention includes a spin waveguide material with a magnetization direction responsive to an electrical signal, used to excite a spin wave signal based on the electrical signal; a receiving antenna located on the spin waveguide material for receiving the electrical signal; a piezoelectric transducer located on the spin waveguide material for converting the spin wave signal into a bandpass-filtered surface acoustic wave signal based on a changing magnetization direction; the excitation of the bandpass-filtered spin wave signal in the spin waveguide material based on the surface acoustic wave signal; and a transmitting antenna located on the spin waveguide material for converting the bandpass-filtered spin wave signal into a bandpass-filtered electrical signal for output. This achieves a wide-bandwidth, high-frequency bandpass filtering effect. Furthermore, the antenna structure of this invention is simple, easy to manufacture, and exhibits no heat loss during spin wave propagation, resulting in lower device power consumption and a shorter spin wave wavelength, which is beneficial for further miniaturization of the device.

[0054] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0055] Those skilled in the art will also understand that the various illustrative logical blocks, units, and steps listed in the embodiments of the present invention can be implemented by electronic hardware, computer software, or a combination of both. To clearly demonstrate the interchangeability of hardware and software, the functions of the various illustrative components, units, and steps described above have been generally described. Whether such functionality is implemented through hardware or software depends on the specific application and the overall system design requirements. Those skilled in the art can implement the described functions using various methods for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of the present invention.

[0056] The various illustrative logic blocks, units, or devices described in the embodiments of this invention can be implemented or operate the described functions using a general-purpose processor, digital signal processor, application-specific integrated circuit (ASIC), field-programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor can be a microprocessor; alternatively, it can be any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented using a combination of computing devices, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration.

[0057] The steps of the methods or algorithms described in the embodiments of this invention can be directly embedded in hardware, a software module executed by a processor, or a combination of both. The software module can be stored in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from and write information to the storage medium. Optionally, the storage medium can also be integrated into the processor. The processor and storage medium can be housed in an ASIC, which can be housed in a user terminal. Optionally, the processor and storage medium can also be housed in different components of the user terminal.

[0058] In one or more exemplary designs, the functions described in the embodiments of the present invention can be implemented in hardware, software, firmware, or any combination of these three. If implemented in software, these functions can be stored on a computer-readable medium or transmitted on a computer-readable medium in the form of one or more instructions or code. Computer-readable media include computer storage media and communication media that facilitate the transfer of computer programs from one place to another. Storage media can be any available media that can be accessed by a general-purpose or special-purpose computer. For example, such computer-readable media can include, but is not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store program code in the form of instructions or data structures and other forms that can be read by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Furthermore, any connection can be suitably defined as a computer-readable medium, for example, if the software is transmitted from a website, server or other remote resource via a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wirelessly, such as infrared, wireless and microwave, it is also included in the defined computer-readable medium. The disks and discs mentioned include compressed disks, laser discs, optical discs, DVDs, floppy disks, and Blu-ray discs. Disks typically copy data magnetically, while disks typically copy data optically using lasers. Combinations of the above can also be contained in computer-readable media.

Claims

1. A bandpass filter device, characterized by, Comprising: a spin waveguide material having a magnetization direction responsive to an electrical signal for exciting a spin wave signal based on the electrical signal, the spin wave signal being bandpass filtered based on a surface acoustic wave signal; a receiving antenna located on the spin waveguide material for receiving the electrical signal; a piezoelectric transducer located on the spin waveguide material for causing a displacement change in a lattice of a piezoelectric material fabricated on a surface of the material based on a changing magnetization direction within the spin waveguide material, the spin wave signal being converted to the bandpass filtered surface acoustic wave signal at an interface of the spin waveguide material and the piezoelectric transducer when a mode of motion of the displacement change reaches a resonant frequency; a transmitting antenna located on the spin waveguide material for outputting the bandpass filtered surface acoustic wave signal after conversion to a bandpass filtered electrical signal.

2. The bandpass filter device of claim 1, wherein, Further comprising: a substrate, the spin waveguide material being located on the substrate.

3. The bandpass filter device of claim 1, wherein, the receiving antenna and the transmitting antenna are symmetrically arranged.

4. The bandpass filter device of claim 1, wherein, the receiving antenna and the transmitting antenna are both coplanar waveguide antennas.

5. The bandpass filter device of claim 4, wherein, the coplanar waveguide antennas include a center conductor strip and conductor planes located on both sides of the center conductor strip.

6. The bandpass filter device of claim 1, wherein, the receiving antenna and the transmitting antenna are both strip antennas.

7. The bandpass filter device of claim 6, wherein, the strip antennas include conductor planes.

8. The bandpass filter device of claim 2, wherein, the spin waveguide material includes yttrium iron garnet ferrite.

9. The bandpass filter device of claim 1, wherein, the piezoelectric transducer includes a zinc oxide thin film, a piezoelectric single crystal, or a piezoelectric ceramic.

10. The bandpass filter device of claim 8, wherein, the substrate includes gadolinium gallium garnet.

Images