CN111847374A - Signal transmitting element for generating very low frequency signal and manufacturing method thereof - Google Patents
Signal transmitting element for generating very low frequency signal and manufacturing method thereof Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/02—Transmitters
- H04B1/04—Circuits
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2201/00—Specific applications of microelectromechanical systems
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- B81B2201/0271—Resonators; ultrasonic resonators
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Abstract
The invention discloses a signal transmitting element for generating a very low frequency signal and a manufacturing method thereof, and relates to the field of radio frequency micro-electronic mechanical systems and the field of antennas. The signal transmitting unit includes: the radiation layer is arranged on one side of a resonance area of the MEMS resonator and is tightly coupled with the resonance area, the other side of the resonance area is fixed on the substrate through an anchor point, and the resonance frequency of the resonance area of the MEMS resonator works in a very low frequency wave band and is used for enabling the magnetostrictive film to generate magnetization oscillation or enabling the electret film to generate charge oscillation to generate a very low frequency signal. The invention can directly realize the integration of the resonator and the radiation layer through the MEMS process without additional installation process, greatly simplifies the process flow, solves the problems of single structure, poor stability and difficult process realization of the VLF transmitting element in the prior patent scheme, and has the advantages of batch manufacture, good consistency, small size, easy realization of array in later period and the like.
Description
Technical Field
The invention relates to the field of radio frequency micro-electro-mechanical systems and antennas, in particular to a signal transmitting element for generating a very low frequency signal and a manufacturing method thereof.
Background
Very Low Frequency (VLF) refers to radio waves with a frequency band from 3KHz to 30 KHz. Because the very low frequency signal has a large penetration depth and high transmission reliability for underground, underwater and the like and has the characteristic of difficult blocking, the VLF communication technology can meet the communication requirements of specific scenes and becomes the focus of communication technology research of military and the like.
However, the VLF communication technology faces a great challenge because the VLF band signal has a wavelength of 10-100km, and even though an electrically small antenna is used as a transmitting element, the VLF communication technology has a huge size, which makes it difficult to be applied in practice, and therefore, the realization of a high-efficiency and portable VLF transmitting element becomes a pursuit direction in military communication fields of various countries.
Disclosure of Invention
The present invention provides a signal transmitting element for generating very low frequency signals, a method for manufacturing the same, and a very low frequency transmitter including the same.
The technical scheme for solving the technical problems is as follows:
A signal transmitting element for generating a very low frequency signal, comprising: a MEMS resonator and a radiating layer, the radiating layer comprising: the radiation layer is arranged on one side of a resonance area of the MEMS resonator, the radiation layer is tightly coupled with the resonance area, the other side of the resonance area of the MEMS resonator is fixed on the substrate through an anchor point, and the resonance frequency of the resonance area of the MEMS resonator works in a very low frequency wave band and is used for enabling the magnetostrictive film to generate magnetization oscillation or enabling the electret film to generate charge oscillation to generate a very low frequency signal.
Another technical solution of the present invention for solving the above technical problems is as follows:
a very low frequency transmitter comprising a signal transmitting element as defined in the above technical solution for generating a very low frequency signal, or generating a very low frequency signal using a signal transmitting element as defined in the above technical solution for generating a very low frequency signal.
Another technical solution of the present invention for solving the above technical problems is as follows:
a method of making a signal transmitting element for generating a very low frequency signal, comprising:
depositing a metal layer on a substrate, covering photoresist on the metal layer according to the pattern and the position of a driving electrode, etching the uncovered metal layer, and removing the photoresist to form the driving electrode after etching is finished;
Continuing to deposit a support layer on the substrate on which the driving electrode is formed, covering photoresist on the support layer according to the pattern and the position of the anchor point, etching the uncovered support layer, and removing the photoresist to form the anchor point after etching is finished;
continuously depositing a sacrificial layer on the substrate with the anchor points, grinding the sacrificial layer to the height of the anchor points, depositing a clamped beam on the ground sacrificial layer, and sputtering a radiation layer on the clamped beam;
and releasing the sacrificial layer to obtain the signal transmitting element for generating the very low frequency signal.
The invention has the beneficial effects that: the radiation layer is coupled on the resonance area of the MEMS resonator, the structure and the size of the MEMS resonator are designed, so that the resonance frequency of the resonance area can work in a very low frequency wave band, the magnetostrictive film is induced to generate magnetization oscillation, or the electret film is induced to generate charge oscillation, and the purpose of radiating electromagnetic waves is achieved.
Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a schematic structural diagram of a signal transmitting unit according to an embodiment of the present invention;
fig. 2 is a schematic structural view of a double-end clamped beam according to another embodiment of the signal transmitting element of the present invention;
fig. 3 is a schematic top view of a double-clamped beam structure according to another embodiment of the signal transmitting element of the present invention;
fig. 4 is a schematic view of a single-ended clamped beam structure according to another embodiment of the signal transmitting element of the present invention;
fig. 5 is a schematic top view of a single-ended clamped beam structure according to another embodiment of the signal transmitting element of the present invention;
FIG. 6 is a schematic structural diagram of a multi-point clamped diaphragm according to another embodiment of the signal transmitter of the present invention;
FIG. 7 is a schematic top view of a fully clamped diaphragm and a multi-point clamped diaphragm according to another embodiment of the signal transmitter of the present invention;
FIG. 8 is a schematic diagram of a manufacturing flow structure provided by an embodiment of a method for manufacturing a signal transmitter according to the present invention;
FIG. 9 is a schematic diagram of a prior art system for generating very low frequency signals using MEMS resonators;
fig. 10 is a schematic diagram of a prior art system for generating very low frequency signals using a magnetostrictive layer.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.
In order to better understand the present invention, a description will first be given of a currently existing very low frequency signal generation scheme.
The field friend of hounwell international corporation, usa, invented a system and method for generating and transmitting ULF/VLF signals, whose core idea is to use MEMS resonators to resonate electrets mounted on a cantilever beam, thereby radiating electromagnetic waves. The cantilever beam is connected with the ground plane through the anchor point, and the electric driver at the root of the cantilever beam is driven by static electricity to vibrate, so that an MEMS resonator is formed, and the radiation power is improved in an MEMS array mode.
The structure is as shown in fig. 9, the electric driver is coupled to the upper surface of the beam and is configured to generate a stress on the beam by the electric bias, the beam and the electret vibrate in a substantially perpendicular direction with respect to the first ground plane and the second ground plane when a stress signal on the beam is generated by the electric actuation, and the vibration of the electret is done at a frequency that produces radiation of ULF or VLF.
However, in the actual production process, the process of mounting the electret under the cantilever beam is very complicated, and in addition, in order to realize the resonant frequency of ULF/VLF, a long cantilever beam length is required, so that the scheme is only a theoretically realizable scheme and is hardly realizable technically. In addition, the MEMS array mentioned in this solution will cause problems such as excessive loss of electromagnetic waves during transmission, phase delay, etc. due to problems of electrical wiring, impedance matching, and defects, which will seriously affect the radiation efficiency and the directional diagram of the antenna.
Furthermore, Junran Xu, Chung Ming Leung, Xin Zhuang et al, at the university of Virginia, in the article "A Low Frequency Mechanical Transmitter Based on magnetic electro insulation semiconductor facility Frequency" and Cunzheng Dongbei university, Yifan He, Menghui Li et al, in the article "A Portable Low Frequency (VLF) Communication System Based on Acoustically activated magnetic electronics Antennas", a scheme for realizing Very Low Frequency emitters Based on a Magnetoelectric stack structure consisting of a Metglas/PZT/Metglas three-layer structure is proposed, wherein the PZT layer is pasted between two electrodes to control the emitting Frequency of the interdigital fingers. In the method, a composite magnetoelectric material is formed by coupling a piezoelectric layer and a magnetostrictive layer, and an alternating voltage is applied to the piezoelectric layer for excitation, so that electromechanical resonance is induced, and the piezoelectric layer is coupled to the magnetostrictive layer to generate magnetization oscillation and radiate electromagnetic waves outwards, wherein the structure is shown in fig. 10.
Although the scheme can reduce the size of the very low frequency transmitter to a great extent, the manufacturing process is relatively complex and difficult to batch. The main reasons for this are: the piezoelectric layer and the magnetostrictive layer of the transmitter are adhered together through glue, the combination degree of the two surfaces is not high, and the magnetoelectric coupling coefficient is not high; secondly, the bulk piezoelectric material needs to be polarized by a strong electric field before installation, so that the dipoles are oriented in the same direction, and difficulty is increased for the manufacturing process; and (III) each transmitter needs to be manufactured independently, so that batch process is difficult to form, and array difficulty is caused.
Based on the very low frequency transmitting element implementation scheme based on the MEMS resonator, the invention provides that a radiation layer is deposited or bonded on the MEMS resonator to realize the VLF signal transmission based on the derived calculation expression of the average radiation power of the magnetized oscillating antenna. And the thickness or the area of the radiation layer is optimally designed, so that the radiation power can be regulated and controlled in a very low frequency band, and the specific implementation mode is as follows.
As shown in fig. 1, a schematic structural diagram is provided for an embodiment of a signal transmitting unit of the present invention, the signal transmitting unit is adapted to generate a very low frequency signal, and includes: MEMS resonator and radiating layer 2, radiating layer 2 includes: the MEMS resonator comprises a magnetostrictive film or an electret film, wherein a radiation layer 2 is arranged on one side of a resonance area 1 of the MEMS resonator, the radiation layer 2 is tightly coupled with the resonance area 1, the other side of the resonance area 1 of the MEMS resonator is fixed on a substrate 4 through an anchor point 3, and the resonance frequency of the resonance area 1 of the MEMS resonator works in a very low frequency wave band and is used for enabling the magnetostrictive film to generate magnetization oscillation or enabling the electret film to generate charge oscillation to generate a very low frequency signal.
The magnetostrictive film can be made of a magnetic material with good soft magnetic property, can be made of a magnetic material with low coercive force, high magnetic conductivity, high saturation magnetization and high magnetostrictive coefficient, can be FeGaB and the like, can be tightly coupled with the resonator through a sputtering or bonding process, and can maximize the thickness of the magnetostrictive film to be not more than 100 mu m under the condition of meeting MEMS process conditions and ensuring the normal oscillation starting of the MEMS resonator.
Electret films can be made using inorganic electret materials, such as silica, or organic electret materials, such as polymers.
It should be understood that, in order to realize the control of the radiation power in the very low frequency band, it is necessary to optimally design the thickness or area of the radiation layer 2, and design the structure and size of the MEMS resonator, so that the resonant frequency of the resonance region 1 operates in the very low frequency band, and then the magnetostrictive film is induced to generate magnetization oscillation, or the electret film is induced to generate charge oscillation, thereby achieving the purpose of radiating electromagnetic waves.
The structure and size of the MEMS resonator are calculated from the derived average radiation power of the magnetized oscillating antenna, which describes the relationship between the average radiation power and the device structure, and an exemplary derivation process is given below by taking the magnetostrictive film as an example.
According to the strain constitutive equation of the magnetostrictive film:
and under the condition of weak magnetic field, H is approximately equal to 0, the relation between the magnetic flux density and the stress can be obtained:
B＝dHT
wherein H is the magnetic field strength, T is the stress, B is the magnetic flux density, muTPermeability of a magnetostrictive film under stress-free conditions, dHIs the piezomagnetic coefficient.
The time-harmonic form of the faraday's law of electromagnetic induction is then combined:
|E0|＝ωh|B|
Wherein E is0Is the aperture electric field, omega is the angular frequency, and h is the magnetostrictive film thickness.
And the mean radiated power is defined as:
wherein, PradIs the average radiation power, η0For free space wave impedance, s is the magnetostrictive film surface area and ds is the area infinitesimal.
Assuming that the stress is a constant value, the average radiation power can be related to the device structure:
based on the above derivation, some preferred numerical ranges for the MEMS resonator are given below.
Preferably, the thickness of the resonance region 1 is 1-100 μm and the surface area is 0.01-2mm2。
Preferably, the radiation layer 2 has a thickness of 1-100 μm and a surface area of 0.01-2mm2。
Preferably, the height of the anchor points 3 is 0.5-10 μm, and the number of anchor points 3 may be 1-16.
This embodiment is through coupling radiation layer 2 on resonance region 1 at MEMS resonator, design through structure and the size to MEMS resonator can make resonance frequency work in resonance region 1 in the very low frequency wave band, and then the induced magnetostriction film takes place the magnetization oscillation, or the induced electret film takes place the charge oscillation, reach the purpose of radiating the electromagnetic wave, because can directly realize the integration of resonator and radiation layer 2 through MEMS technology, need not additional installation technology, the process flow has been simplified greatly, the problem that VLF emission element structure is single in the solution of the existing patent, poor stability and technology realization are difficult is solved, but batch manufacturing, the uniformity is good, the size is little, later stage easily realizes advantages such as array.
Compared with the scheme of utilizing the MEMS resonator to enable the electret arranged on the cantilever beam to generate resonance, the decoupling of the cantilever beam type MEMS resonator is realized, and diversified MEMS resonators such as a double-end clamped beam 6, a single-end clamped beam 7, a multi-point supporting beam, a diaphragm type and the like can be adopted. Therefore, the frequency can be regulated and controlled, and the structures of the double-end clamped beam 6, the full clamped membrane, the multi-point clamped membrane 8, the multi-point supporting beam and the like are also beneficial to the stability of the structure. Most importantly, the scheme can directly realize the integration of the resonator and the radiation layer 2 through the MEMS process, and the subsequent manufacturing method embodiment is detailed without additional installation process and considering how to fix the electret on the beam, thereby greatly simplifying the process flow.
Compared with the scheme of realizing the very low frequency transmitting element based on the magnetoelectric laminated structure, the embodiment completes the upgrade from the mesoscale to the microscale and further realizes the size reduction of the transmitting element. In addition, the resonance region 1 of the MEMS resonator can be tightly coupled with the radiation layer 2 by utilizing a magnetron sputtering or bonding process, and compared with an adhesion method, the method is more favorable for stress transfer, and the coupling efficiency can be greatly improved. The MEMS resonator is driven by static electricity, the material does not need to be subjected to pre-polarization induction compared with piezoelectric driving, meanwhile, the whole transmitter is prepared by an MEMS process, and the MEMS resonator has the advantages of batch manufacturing, good consistency, easiness in realizing array in the later period and the like, and compared with the scheme, the size can be effectively reduced by about 9 orders of magnitude.
Optionally, in some possible embodiments, a drive electrode 5 is provided on the substrate 4, the drive electrode 5 being located between the substrate 4 and the resonance region 1 for driving the MEMS resonator.
Preferably, the MEMS resonator can be electrostatically driven, the driving voltage is applied to the driving electrode 5, the driving electrode 5 is deposited above the substrate 4 below the resonance region 1 by a sputtering process, and the thickness of the driving electrode 5 can be 0.5-5 μm.
Optionally, in some possible embodiments, as shown in fig. 2 and fig. 3, which show a schematic structural diagram and a top view of the clamped-clamped beam 6, the resonance region 1 includes: the radiation layer is arranged on one side of the double-end clamped beam 6, and two ends of the other side of the double-end clamped beam 6 are fixed on the substrate 4 through anchor points 3 respectively.
As shown in fig. 2, the driving electrode 5 is disposed in the middle portion of the substrate 4, the anchor points 3 are disposed at both ends of the double clamped beam 6, as shown in fig. 3, the hatched portions on the left and right sides represent the anchor points 3, the hatched portion in the middle represents the driving electrode 5, and the driving electrode 5 may be rectangular.
And the double-end clamped beam 6 is adopted, so that the stability of the structure is facilitated.
Optionally, in some possible embodiments, as shown in fig. 4 and fig. 5, a schematic structural diagram and a top view of the single-ended clamped beam 7 are given, and the resonance region 1 includes: the single-end clamped beam 7 is characterized in that a radiation layer 2 is arranged on one side of the single-end clamped beam 7, and one end of the other side of the single-end clamped beam 7 is fixed on the substrate 4 through an anchor point 3.
As shown in fig. 4, in order to improve the driving effect of the driving electrode 5, when the single-ended clamped beam 7 is used, the driving electrode 5 may be disposed at the other end opposite to the anchor point 3, one end of the single-ended clamped beam 7 is connected to the substrate 4 through the anchor point 3, as shown in fig. 5, the left hatching indicates the driving electrode 5, the right hatching indicates the anchor point 3, and the driving electrode 5 may be rectangular.
Alternatively, in some possible embodiments, as shown in fig. 6 and 7b, which show a schematic structural diagram and a top view of the multi-point clamped diaphragm 8, the resonance region 1 includes: the multi-point clamped diaphragm 8 is characterized in that a radiation layer 2 is arranged on one side of the multi-point clamped diaphragm 8, and a plurality of end points on the other side of the multi-point clamped diaphragm 8 are fixed on the substrate 4 through anchor points 3 respectively.
For the multi-point fixed-support diaphragm 8, as shown in fig. 6, the number and shape of the anchor points 3 may be set according to actual requirements, as shown in fig. 7b, the diaphragm shown therein adopts multi-point support, it should be understood that, in order to realize stable support, the number of the anchor points 3 is at least 3, and the anchor points are axisymmetrically distributed or centrosymmetrically distributed, the outer ring shaded small circle in fig. 7b is the anchor point 3, the total number is 8, and the middle circle part shaded is the driving electrode 5.
Optionally, in some possible embodiments, the resonance region 1 may include: the fully clamped diaphragm is formed by a circle of closed anchor points around, so that as shown in figure 2, a cross section of the fully clamped diaphragm along a midline is the same as a front view of a double-end clamped beam, figure 7a shows a structural top view of the fully clamped diaphragm, a radiation layer 2 is arranged on one side of the fully clamped diaphragm, and the other side of the fully clamped diaphragm is fixed on a substrate 4 through the anchor points 3.
Fig. 7a shows that the whole diaphragm of the fully clamped diaphragm is anchored to form a closed structure, the shaded portion of the outer ring is the anchor point 3, at this time, the driving electrode 5 can be circular, and the shaded portion of the middle circle is the driving electrode 5.
By adopting the multi-point clamped membrane 8 and the full clamped membrane, the stability of the structure is facilitated.
Optionally, in some possible embodiments, the shape of the multi-point clamped membrane 8 is circular, rectangular or diamond.
Optionally, in some possible embodiments, the shape of the fully clamped membrane is circular, rectangular or diamond.
Alternatively, in some possible embodiments, the magnetostrictive film comprises a hard axis and an easy axis induced by an induced magnetic field, and the hard axis and the easy axis are orthogonal to each other in the plane of the magnetostrictive film.
Optionally, during the deposition of the magnetostrictive film, a magnetron sputtering process may be adopted, and a 100-1500Oe induction magnetic field is applied during the sputtering process, so that the magnetostrictive film forms a hard axis and an easy axis.
Optionally, in some possible embodiments, a uniformly inserted layer of insulating medium is provided within the magnetostrictive film.
It is understood that the magnetostrictive film can regulate the soft magnetic property by uniformly inserting an insulating medium layer, wherein the electric conductivity of the insulating medium layer can be 0-100S/m, the thickness can be 5-20nm, the number of inserting layers can be 3-40, and the material can be Al2O3、Si3N4AlN and the like.
By inserting the insulating medium layer into the magnetostrictive film, the soft magnetic characteristic of the magnetostrictive film can be better regulated, so that the electromagnetic wave radiated by the magnetostrictive film is controllable in high precision.
It is to be understood that some or all of the various embodiments described above may be included in some embodiments.
As shown in fig. 8, a schematic diagram of a manufacturing flow structure provided in an embodiment of a method for manufacturing a signal transmitting element of the present invention is used to manufacture the signal transmitting element, the signal transmitting element is used to generate a very low frequency signal, and the manufacturing method includes:
As shown in fig. 8a, a metal layer 20 is deposited on the substrate 10, as shown in fig. 8b, a photoresist 30 is coated on the metal layer 20 according to the pattern and position of the driving electrode, as shown in fig. 8c, the metal layer 20 which is not coated is etched, and after the etching is completed, the photoresist 30 is removed, and the driving electrode is formed.
The substrate 10 may be a silicon substrate, the material of the metal layer 20 may be aluminum, gold, or the like, and the photoresist 30 is a positive photoresist.
Specifically, the metal layer 20 may be patterned on the surface of the metal layer 20 by a photolithography process, the metal layer 20 not covered by the photoresist 30 is etched by a dry etching process, and the photoresist 30 is removed by a plasma bombardment method after the etching is completed, so as to form the driving electrode.
As shown in fig. 8d, the supporting layer 40 is deposited on the substrate 10 after the driving electrodes are formed, and as shown in fig. 8e, the supporting layer 40 is covered with the photoresist 30 according to the pattern and the position of the anchor points, and since the double-clamped beam 60 structure is fabricated, the photoresist 30 can be covered on both ends of the supporting layer 40, so as to generate two anchor points. The uncovered support layer 40 is etched, and after etching is complete, the photoresist 30 is removed, forming anchors, as shown in fig. 8 f. At this time, the driving electrode is deposited on the substrate 10 at the middle portion, and the anchor points are deposited on both ends of the substrate 10.
The material of the support layer 40 may be polysilicon, the thickness may be 0.5-5 μm, and the photoresist 30 is positive photoresist.
Specifically, the surface of the support layer 40 may be patterned by a photolithography process, the support layer 40 not covered by the photoresist 30 is etched by a dry etching process, and the photoresist 30 is removed by a plasma bombardment method after the etching is completed, thereby forming anchor points.
As shown in fig. 8g, the sacrificial layer 50 is deposited on the substrate 10 after the anchor points are formed, as shown in fig. 8h, the sacrificial layer 50 is polished to the height of the anchor points, as shown in fig. 8i, clamped beams are deposited on the polished sacrificial layer 50, and the radiation layer 70 is sputtered on the clamped beams.
Specifically, the sacrificial layer 50 may be deposited using a chemical vapor deposition process, and the sacrificial layer 50 may be planarized using a chemical mechanical polishing process to the height of the anchor point.
Alternatively, the double-ended clamped beam 60 may be the same material as the support layer 40, with the double-ended clamped beam 60 having a thickness of 1-100 μm. A magnetron sputtering process may be used to sputter the radiation layer 70 on the surface of the clamped-clamped beam 60.
As shown in fig. 8j, the sacrificial layer 50 is released, resulting in a double clamped beam 60 structure.
It should be understood that before fabrication, finite element simulation is used to obtain the initial size of the resonator corresponding to the frequency range in which the radiating element operates. For example, for a clamped-clamped beam 60 structure MEMS resonator, the design frequency may be 25kHz to meet very low frequency bands, the beam length may be 960 μm, and the beam thickness may be 5 μm.
In order to increase the average radiation power of the transmitting element to the maximum extent, the area of the resonance area of the resonator needs to be maximized, and the beam length can be further increased to more than 1 mm. However, beam length adjustment affects the resonator operating frequency and device stability, and can be further manipulated by increasing the beam thickness to more than 10 μm in order to deposit a sufficiently thick radiating layer 70 over the resonance region.
The values of the parameters are regulated and controlled according to the expression, finite element simulation is utilized again, the structural size of the very low frequency transmitting element based on the MEMS resonator is determined, and the double-end clamped beam 60 structure can be manufactured according to the obtained structural size.
By the manufacturing method, the integration of the resonator and the radiation layer can be directly realized through the MEMS process, an additional installation process is not needed, the process flow is greatly simplified, and the manufacturing method has the advantages of batch manufacturing, good consistency, easiness in realizing array in the later period and the like.
The invention also provides a very low frequency transmitter, which comprises the signal transmitting element for generating the very low frequency signal provided by any embodiment above, or generates the very low frequency signal by using the signal transmitting element for generating the very low frequency signal provided by any embodiment above.
Optionally, for better generation of the very low frequency signal, a plurality of signal transmitting elements may be packaged into an array, and the array is applied to the very low frequency transmitter.
The reader should understand that in the description of this specification, reference to the description of the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described method embodiments are merely illustrative, and for example, the division of steps into only one logical functional division may be implemented in practice in another way, for example, multiple steps may be combined or integrated into another step, or some features may be omitted, or not implemented.
While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A signal transmitting element for generating a very low frequency signal, comprising: a MEMS resonator and a radiating layer, the radiating layer comprising: the radiation layer is arranged on one side of a resonance area of the MEMS resonator, the radiation layer is tightly coupled with the resonance area, the other side of the resonance area of the MEMS resonator is fixed on the substrate through an anchor point, and the resonance frequency of the resonance area of the MEMS resonator works in a very low frequency wave band and is used for enabling the magnetostrictive film to generate magnetization oscillation or enabling the electret film to generate charge oscillation to generate a very low frequency signal.
2. A signal-transmitting element for generating very low frequency signals as claimed in claim 1, characterized in that a driving electrode is provided on the substrate, which driving electrode is located between the substrate and the resonance region for driving the MEMS resonator.
3. A signal-transmitting element for generating very low frequency signals according to claim 1, characterized in that said resonance region comprises: the radiation layer is arranged on one side of the double-end clamped beam, and two ends of the other side of the double-end clamped beam are fixed on the substrate through anchor points respectively.
4. A signal-transmitting element for generating very low frequency signals according to claim 1, characterized in that said resonance region comprises: the radiation layer is arranged on one side of the single-end clamped beam, and one end of the other side of the single-end clamped beam is fixed on the substrate through an anchor point.
5. A signal-transmitting element for generating very low frequency signals according to claim 1, characterized in that said resonance region comprises: the radiation layer is arranged on one side of the multi-point clamped diaphragm, and a plurality of end points on the other side of the multi-point clamped diaphragm are fixed on the substrate through anchor points respectively.
6. A signal-transmitting element for generating very low frequency signals according to claim 1, characterized in that said resonance region comprises: the radiation layer is arranged on one side of the full clamped diaphragm, and the other side of the full clamped diaphragm is fixed on the substrate through an anchor point.
7. The signal emitter for generating very low frequency signals according to any of claims 1 to 6, wherein said magnetostrictive film comprises a hard axis and an easy axis induced by an induced magnetic field, said hard axis and said easy axis being orthogonal to each other in the plane of said magnetostrictive film.
8. Signal emitter cell for generating very low frequency signals according to one of the claims 1 to 6, characterized in that said magnetostrictive film is provided with a uniformly inserted layer of insulating medium.
9. A very low frequency transmitter comprising a signal transmitting unit for generating a very low frequency signal according to any one of claims 1 to 8, or a very low frequency signal generated using a signal transmitting unit for generating a very low frequency signal according to any one of claims 1 to 8.
10. A method of making a signal transmitting element for generating a very low frequency signal, comprising:
depositing a metal layer on a substrate, covering photoresist on the metal layer according to the pattern and the position of a driving electrode, etching the uncovered metal layer, and removing the photoresist to form the driving electrode after etching is finished;
continuing to deposit a support layer on the substrate on which the driving electrode is formed, covering photoresist on the support layer according to the pattern and the position of the anchor point, etching the uncovered support layer, and removing the photoresist to form the anchor point after etching is finished;
Continuously depositing a sacrificial layer on the substrate with the anchor points, grinding the sacrificial layer to the height of the anchor points, depositing a clamped beam on the ground sacrificial layer, and sputtering a radiation layer on the clamped beam;
and releasing the sacrificial layer to obtain the signal transmitting element for generating the very low frequency signal.
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| CN114512791A (en) * | 2022-01-28 | 2022-05-17 | 安徽大学 | Dual-frequency very-low-frequency antenna |
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