阅读说明：本技术 一种频率在c、x波段转换的切伦科夫微波发生器 (Cerenkov microwave generator with frequency converted in C, X wave band ) 是由 葛行军 赵晨煜 邓如金 冷吴西 闫皓 皇甫思涵 张鹏 黄超 宋莉莉 贺军涛 张军 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种频率在C、X波段转换的切伦科夫微波发生器,所述螺线管磁场内设置有阴极座、阴极、阳极外筒、截止颈、C波段慢波结构、漂移段、X波段慢波结构和微波输出口,整个结构相对于中心轴线旋转对称,使两个波段均能实现较高的束-波作用效率。通过设计漂移段的长度和半径,在与前后两个慢波叶片呈阶梯状分布时,能对两个波段的束-波作用分别产生具有最优效果的峰值。(The invention discloses a Cerenkov microwave generator with frequency converted in C, X wave band, wherein a cathode seat, a cathode, an anode outer cylinder, a cut-off neck, a C-band slow wave structure, a drift band, an X-band slow wave structure and a microwave output port are arranged in a solenoid magnetic field, and the whole structure is rotationally symmetrical relative to a central axis, so that higher beam-wave action efficiency can be realized in both wave bands. By designing the length and the radius of the drift section, when the drift section and the front and rear slow wave blades are distributed in a step shape, the peak values with optimal effects can be respectively generated on the beam-wave action of the two wave sections.)

1. A Cerenkov microwave generator with frequency converted in C, X wave band comprises a solenoid magnetic field, and is characterized in that a cathode seat, a cathode, an anode outer cylinder, a stop neck, a C-band slow-wave structure, a drift section, an X-band slow-wave structure and a microwave output port are arranged in the solenoid magnetic field, the whole structure is rotationally symmetric relative to a central axis, the C-band slow-wave structure, the drift section and the X-band slow-wave structure are arranged in the solenoid magnetic field, the outlet end of the cathode seat is connected with the inlet end of the cathode, the outlet end of the cathode is sleeved at the inlet end of the anode outer cylinder, the outlet end of the anode outer cylinder is connected with the inlet end of the stop neck, the outlet end of the stop neck is connected with the inlet end of the C-band slow-wave structure, and the outlet end of the C-band slow-, the outlet end of the drift section is connected with the inlet end of the X-waveband slow-wave structure, and the outlet end of the X-waveband slow-wave structure is connected with the microwave output port.

2. The cerenkov microwave generator with C, X waveband conversion frequency according to claim 1, wherein the cathode is a high hardness graphite cathode or a pyrex-cloth-epoxy copper clad laminate cathode.

3. The Cerenkov microwave generator with C, X band switching frequency according to claim 1, wherein the solenoid magnetic field is formed by winding enameled copper wire or glass fiber-covered copper wire.

4. The cerenkov microwave generator with C, X waveband conversion of frequency according to claim 1, wherein the left end of the cathode base is externally connected with an inner conductor of a pulse power driving source.

5. The Cerenkov microwave generator with C, X waveband conversion frequency according to claim 1, wherein the left end of the anode outer cylinder is externally connected with an external conductor of a pulse power driving source.

6. A cerenkov microwave generator with a frequency conversion in the C, X band as claimed in claim 1, wherein said cathode is a thin-walled cylindrical cathode having a radius equal to the radius of the electron beam.

7. A cerenkov microwave generator with a frequency conversion at the C, X band as claimed in claim 1, wherein said cutoff neck is in the shape of a circular disk, and the inner radius of the cutoff neck is greater than the inner radius of the cathode.

8. The cerenkov microwave generator with frequency conversion at C, X waveband of claim 1, wherein the slow wave structure comprises two sections of a first slow wave structure and a second slow wave structure separated by a drift section, the first slow wave structure is composed of 10 slow wave blades, the second slow wave structure is composed of 6 slow wave blades, the inner surface of each slow wave blade is a rectangular structure, the cycle lengths of the rest slow wave blades except the first slow wave blade are 2.8cm in the C-waveband slow wave structure are all 2.6cm, and the cycle lengths of the rest slow wave blades except the fifth and seventh slow wave blades are all 1.3cm in the X-waveband slow wave structure are all 1.2 cm; the C-band slow wave structure works in a C band, the working frequency is 4.2GHz, the X-band slow wave structure works in an X band, and the working frequency is 8.6 GHz.

9. The Cerenkov microwave generator with frequency conversion at C, X bands of claim 1, wherein the operating magnetic field of the C-band slow-wave structure corresponding to the band is 1.30-2.05T, and is the cyclotron resonance absorption magnetic field of the X-band slow-wave structure corresponding to the band, and the operating magnetic field of the X-band slow-wave structure corresponding to the band is 0.60-0.75T, and is the cyclotron resonance absorption magnetic field of the C-band slow-wave structure.

10. The Cerenkov microwave generator with C, X waveband conversion frequencies as claimed in claim 1, wherein the drift section is disc-shaped, the drift section and the front and rear slow wave structures are distributed in a ladder-shaped manner, and the inner radius ratio of the drift section is larger than the inner radius of the C-waveband slow wave structure and smaller than the outer radius of the X-waveband slow wave structure.

Technical Field

The invention relates to the field of microwave sources, in particular to a Cerenkov microwave generator with frequency converted in C, X wave band.

Background

The high-power microwave is one kind of strong electromagnetic pulse, is generally defined as electromagnetic wave with power greater than 100MW and frequency between 0.1-100GHz, has the characteristics of high power, directional radiation and the like, and has wide application prospect in the fields of civil science and technology, national defense and military, such as plasma fusion, high-energy particle accelerators, ultra-long distance radars, directional energy weapons and the like. In the last 70 th century, with the development of pulsed power technology, relativistic electronics and plasma physics, traditional electrovacuum devices combined with a high current relativistic electron beam formed relativistic electrovacuum devices capable of generating high power microwaves, i.e. high power microwave sources. The high-power microwave source converts the energy of a high-current electron beam into the energy of high-power microwaves by using a special electromagnetic structure, and is a core component of a system for generating the high-power microwaves. The high-power microwave source technology is rapidly developed under the traction of civil and military application.

The practical application puts higher and higher requirements on high-power microwave sources, and the development trend is shown as follows: firstly, a single high-power microwave source pursues higher indexes under the conditions of certain volume and weight limitation, namely, the output microwave power and the pulse width are further improved, the repeated operation frequency is improved, and the like; secondly, power synthesis is carried out on a plurality of high-power microwave sources by using a frequency locking and phase locking technology, so that high-power output is obtained; and thirdly, a small high-power microwave device which is tunable, repeatable and stable in operation is developed. At present, cerenkov devices are deeply researched in the former two aspects, become one of high-power microwave source devices with the most application prospect, are also hot spots in the research field of high-power microwave source devices, and particularly have obvious advantages in the aspects of high power, long pulse width, high repetition frequency and the like, and are specifically shown in the following steps: the microwave generating mechanism utilizes a slow wave structure to reduce the phase velocity of electromagnetic waves so as to enable the electromagnetic waves to have Cerenkov interaction with electron beams, and because the electron beams are generally restricted by a strong magnetic field, the energy divergence of the electron beams is small, the consistency is good, and the energy conversion efficiency of the beam waves is high; a foil-free diode is usually adopted, and compared with a foil diode, the problem that an electron beam directly bombards an anode foil to generate anode plasma can be avoided, so that the problem of microwave pulse shortening caused by diode closing due to expansion of the anode plasma can be avoided; in addition, the structure of the foil-free diode is also beneficial to the rapid recovery of the internal vacuum degree in the working process of the device, so that the repeated frequency operation can be realized.

The frequency-tuned high-power microwave source can be applied to a high-power microwave system, and can bind microwave frequencies on line according to different action targets to enhance the action effect. In addition, the frequency-tuned high-power microwave source can also be applied to the research of high-power microwave effect. Therefore, the frequency tuning high-power microwave source technology has important application value in the national defense and industrial fields and becomes one of the important development directions of the high-power microwave source, and the frequency tuning mode of the high-power microwave source mainly comprises an electric tuning mode and a mechanical tuning mode. The electric tuning means realizes the tuning of working frequency by changing the external voltage and the size of a guide magnetic field, the mechanical tuning means realizes the tuning of working frequency by changing the electrodynamic structure of a device, and the common tuning technology at home and abroad at present is mostly realized based on a mechanical tuning mode.

C-band (4GHz-8GHz) and X-band (8GHz-12GHz) microwaves have considerable application prospects in the aspects of radar, communication, remote sensing and the like, and become a new research hotspot in the field of high-power microwaves. Therefore, the research on the Cerenkov microwave generator with the frequency capable of being converted at the C, X waveband has important practical value.

The existing frequency modulation device has a complex adjustment mode, and a plurality of structural parameters are usually required to be adjusted by more than 2) under the condition of keeping high vacuum; the adjustment bandwidth of the radiation frequency is often narrow, and is mostly fine-tuned in a certain band.

Therefore, it is needed to develop a technology for adjusting a high-power microwave source across a wavelength band, which has a large operating frequency adjustment bandwidth and a simple structural parameter adjustment manner, by using a new design concept, and therefore, a cerenkov microwave generator with frequency conversion at C, X wavelength band, which can effectively solve the above problems, is needed.

Disclosure of Invention

The invention aims to provide a Cerenkov microwave generator with frequency converted in C, X wave band, and in order to realize the purpose, the invention adopts the following technical scheme:

the invention comprises a solenoid magnetic field, a cathode seat, a cathode, an anode outer cylinder, a stop neck, a C-waveband slow-wave structure, a drift section, an X-waveband slow-wave structure and a microwave output port are arranged in the solenoid magnetic field, the whole structure is rotationally symmetrical relative to a central axis, the C-waveband slow-wave structure, the drift section and the X-waveband slow-wave structure are arranged in the solenoid magnetic field, the outlet end of the cathode seat is connected with the inlet end of the cathode, the outlet end of the cathode is sleeved at the inlet end of the anode outer cylinder, the outlet end of the anode outer cylinder is connected with the inlet end of the stop neck, the outlet end of the stop neck is connected with the inlet end of the C-waveband slow-wave structure, the outlet end of the C-waveband slow-wave structure is connected with the inlet end of the drift section, and the outlet, and the outlet end of the X-waveband slow wave structure is connected with the microwave output port.

Further, the cathode 502 is a high-hardness graphite cathode or a pyrex-cloth-epoxy resin copper-clad plate cathode.

Specifically, the solenoid magnetic field is formed by winding enameled copper wires or glass fiber-covered copper wires.

Furthermore, the left end of the cathode base is externally connected with an inner conductor of a pulse power driving source.

Specifically, the left end of the anode outer cylinder is externally connected with an outer conductor of a pulse power driving source.

Further, the cathode is a thin-walled cylindrical cathode having a cathode radius equal to the radius of the electron beam.

Specifically, the cut-off neck is in a disc shape, and the inner radius of the cut-off neck is larger than that of the cathode.

Furthermore, the slow wave structure comprises a first slow wave structure and a second slow wave structure which are isolated by a drift section, the first slow wave structure comprises 4 slow wave blades, the second slow wave structure comprises 6 slow wave blades, the inner surface of each slow wave blade is of a rectangular structure, in the C-band slow wave structure, except that the cycle length of the first slow wave blade is 2.8cm, the cycle lengths of the rest slow wave blades are 2.6cm, in the X-band slow wave structure, except that the cycle lengths of the fifth and seventh slow wave blades are 1.3cm, the cycle lengths of the rest slow wave blades are 1.2 cm; the C-band slow wave structure works in a C band, the working frequency is 4.2GHz, the X-band slow wave structure works in an X band, and the working frequency is 8.6 GHz.

Specifically, the working magnetic field of the wave band corresponding to the C-band slow wave structure is 1.30-2.05T, and is a cyclotron resonance absorption magnetic field of the X-band slow wave structure, and the working magnetic field of the wave band corresponding to the X-band slow wave structure is 0.60-0.75T, and is a cyclotron resonance absorption magnetic field of the C-band slow wave structure.

Furthermore, the drift section is disc-shaped, the drift section and the front and rear slow wave structures are distributed in a ladder shape, and the inner radius ratio of the drift section is larger than the inner radius of the C-waveband slow wave structure and smaller than the outer radius of the X-waveband slow wave structure.

Compared with the prior art, the invention has the following beneficial effects:

1. the Cerenkov microwave generator with the frequency converted in C, X wave band and capable of hopping across C, X wave band provided by the invention adopts a two-section hollow slow wave structure isolated by 1 drift band to respectively excite a first section of hollow slow wave structure TM₀₁Mode and second-section hollow slow-wave structure TM₀₁The mode, which undergoes beam-wave interaction with the electron beam, needs to undergo two beam modulations. The drift section reduces the mutual influence among microwaves of different wave bands,so that the two wave bands can realize higher beam-wave action efficiency. By designing the length and the radius of the drift section, when the drift section and the front and rear slow wave blades are distributed in a step shape, the peak values with optimal effects can be respectively generated on the beam-wave action of the two wave sections.

2. The Cerenkov microwave generator with the frequency converted in the C, X wave band provided by the invention shares the rest electromagnetic structures and the additional solenoid magnetic field in the device, and the position and the amplitude of the generated magnetic field can be changed only by changing one parameter of the current of the solenoid magnetic field, so that the working state of the device is converted in the C, X wave band. The size of the magnetic field has a significant influence on the working band and beam-wave action efficiency of the output microwaves: when the magnetic field is 1.30-2.05T, the magnetic field works in the C wave band, and when the magnetic field is 1.5T, the highest beam-wave action efficiency is achieved; when the magnetic field is in the range of 0.60-0.75T, the device works in the X wave band, and when the magnetic field is in the range of 0.7T, the highest beam-wave action efficiency is achieved, a complex mechanical adjusting system is not needed, the size and the weight of the device are reduced, and the device is light and small.

Drawings

FIG. 1 is a cross-sectional view of a preferred embodiment of a Cerenkov microwave applicator with a frequency conversion in the C, X band, according to the present invention;

FIG. 2 is a schematic cross-sectional perspective view of a preferred embodiment of a Cerenkov microwave generator of the present invention with frequency switching at the C, X band;

FIG. 3 is a graph illustrating the effect of the drift length on the beam efficiency of a preferred embodiment of a Cerenkov microwave generator of the present invention with frequency switching at the C, X band;

FIG. 4 is a graph illustrating the effect of the shifted radius on the beam efficiency of a preferred embodiment of a Cerenkov microwave generator of the present invention with frequency switching at the C, X band;

fig. 5 is a schematic diagram showing the effect of the magnetic field size of the preferred embodiment of the cerenkov microwave generator with frequency conversion at C, X on the output microwave beam-wave action efficiency.

FIG. 6 is a graph showing the time variation trend of C-band microwaves of a preferred embodiment of a Cerenkov microwave generator according to the present invention, wherein the frequency of the Cerenkov microwave generator is converted at C, X;

FIG. 7 is a graph showing the time-dependent variation trend of X-band microwaves of a preferred embodiment of a Cerenkov microwave generator according to the present invention, wherein the frequency of the Cerenkov microwave generator is converted at C, X;

Detailed Description

The present invention is further illustrated by the following examples, which are intended to be in a manner including, but not limited to, the following examples.

Referring to fig. 1 and 2, the present invention is composed of two sections of slow wave structures respectively corresponding to different wave bands, and the present invention has a simple structure, and includes a cathode base 501; a cathode 502; an anode outer cylinder 503; a shut-off neck 504; c-band slow-wave structure 505a (with an operating wavelength of lambda)₁) (ii) a A drift section 506; an X-band slow-wave structure 505b (with an operating wavelength of λ)₂) (ii) a A microwave output port 507; a solenoid magnetic field 508. The entire structure is rotationally symmetric about the central axis. The electromagnetic wave type microwave oven comprises a solenoid magnetic field, and is characterized in that a C-waveband slow-wave structure, a drift section and an X-waveband slow-wave structure are arranged in the solenoid magnetic field, the outlet end of a cathode base is connected with the inlet end of a cathode, the outlet end of the cathode is sleeved with the inlet end of an anode outer cylinder, the outlet end of the anode outer cylinder is connected with the inlet end of a stop neck, the outlet end of the stop neck is connected with the inlet end of the C-waveband slow-wave structure, the outlet end of the C-waveband slow-wave structure is connected with the inlet end of the drift section, the outlet end of the drift section is connected with the inlet end of the X-waveband slow-wave structure, and.

The cathode base 501 and the anode outer cylinder 503 are usually made of non-magnetic stainless steel materials, the stop neck 504, the C-band slow-wave structure 505a, the X-band slow-wave structure 505b and the drift section 506 are usually made of non-magnetic stainless steel, oxygen-free copper or titanium and the like, the cathode 502 can be made of high-hardness graphite or heat-resistant glass cloth-epoxy resin copper-clad plate (FR-5) materials, and the solenoid magnetic field 508 is formed by winding enameled copper wires or glass-wire copper-clad wires. The left end of the cathode base 501 is externally connected with an inner conductor of a pulse power driving source, and the left end of the anode outer cylinder 503 is externally connected with an outer conductor of the pulse power driving source.

The cathode is a thin-wall cylinder, is sleeved at the right end of the cathode seat, has the wall thickness of 0.1cm and the cathode radiusR₁Equal to the radius of the electron beam. The cut-off neck is in a disc shape and has an inner radius of R₂，R₂＞R₁In order to effectively cut off the microwaves generated in the beam action region, the specific size needs to be optimally designed according to the operating wavelengths of the two bands. The slow wave structure comprises a first slow wave structure and a second slow wave structure which are isolated through a drift section, the first slow wave structure and the second slow wave structure are composed of 10 slow wave blades, the first slow wave structure is composed of 4 slow wave blades, the second slow wave structure is composed of 6 slow wave blades, the inner surface of each slow wave blade is of a rectangular structure, and the outer radius of the C-waveband slow wave structure is R₃Inner radius of R₄The outer radius of the X-band slow wave structure is R₅Inner radius of R₆Satisfy R₃＞R₅＞R₄＞R₆＞R₁(ii) a In the C-band slow-wave structure, except that the cycle length of the first slow-wave blade is 2.8cm, the cycle lengths of the other slow-wave blades are 2.6cm, and in the X-band slow-wave structure, except that the cycle lengths of the fifth and seventh slow-wave blades are 1.3cm, the cycle lengths of the other slow-wave blades are 1.2 cm; the C-band slow-wave structure works in a C band with the working frequency of 4.2GHz, the X-band slow-wave structure works in an X band with the working frequency of 8.6GHz, and the working modes of the two-segment slow-wave structure are both hollow slow-wave structure TM₀₁Pi mode of mode; the working magnetic field of the wave band corresponding to the C-band slow wave structure is 1.30-2.05T, and is a cyclotron resonance absorption magnetic field of the X-band slow wave structure, the working magnetic field of the wave band corresponding to the X-band slow wave structure is 0.60-0.75T, and is a cyclotron resonance absorption magnetic field of the C-band slow wave structure, due to the phenomenon of cyclotron resonance absorption, the change of the size of the magnetic field can only excite the high-efficiency single-frequency oscillation of the corresponding wave band, and the other mode can not excite, so that the mode competition is effectively inhibited, and the cross-band frequency modulation is realized. 1 drift section in a disc shape is arranged between two sections of slow wave structures, the length of the drift section is 3.1cm, and the inner radius R₇3.9cm, the drift section and the front and back slow-wave structures are distributed in a ladder shape, the inner radius of the drift section is 0.2cm higher than that of the C-waveband slow-wave structure and 0.2cm lower than that of the X-waveband slow-wave structure, and the requirement that R is met₅＞R₇＞R₄. The electron beam emitted from the cathode passes through twoAfter the slow wave structure is segmented, the slow wave structure is directly shot on the outer wall to be collected, the distance between the slow wave structure and the last slow wave blade is 4.2cm, and the distance between the slow wave structure and the last slow wave blade is 5cm from the output port, so that a special collection structure is not required to be designed, and the whole structure is simple. The solenoid magnetic field is sleeved on the outer wall of the anode outer cylinder, and can generate an axial magnetic field for restraining electron beams, and the axial magnetic field can be changed only by changing the current for supplying the solenoid magnetic field without carrying out complicated mechanical operation. The right end of the microwave output port is connected with an antenna, and the antenna can be designed according to the design method of a universal antenna according to the requirements of different wavelengths.

When the invention is operated, the size of the current of the solenoid magnetic field is adjusted: 1) the axial magnetic field is in 1.30-2.05T, the strong current relativistic electron beam emitted by the cathode is guided by the magnetic field and transmitted to the two sections of hollow slow wave action areas, and in the hollow slow wave action areas, the electron beam and the hollow TM are₀₁The mode generates a beam-wave action, energy is given to a microwave field, the microwave field undergoes beam modulation twice, the magnetic field is positioned in a working area of a C-waveband slow-wave structure and a cyclotron resonance absorption area of an X-waveband slow-wave structure, so that microwaves of an X waveband are inhibited, only single-frequency oscillation of the C-waveband microwaves can be excited, and high-power microwaves are radiated out after passing through an output waveguide purification mode; 2) the axial magnetic field is in 0.60-0.75T, the strong current relativistic electron beam emitted by the cathode is guided by the magnetic field and transmitted to the two sections of hollow slow wave action areas, and in the hollow slow wave action areas, the electron beam and the hollow TM are₀₁The mode generates beam-wave action, energy is given to a microwave field, the microwave field undergoes beam modulation twice, the magnetic field is positioned in a cyclotron resonance absorption area of a C-waveband slow-wave structure and a working area of an X-waveband slow-wave structure, therefore, C-waveband microwaves are inhibited, only single-frequency oscillation of the X-waveband microwaves can be excited, and high-power microwaves are radiated out after passing through an output waveguide purification mode.

The embodiment realizes C crossing (the central frequency is 4.2GHz, corresponding to the wavelength lambda of microwave)₁7.1cm), X (center frequency of 8.6GHz, corresponding to microwave wavelength λ₂3.5cm) frequency tunable cerenkov microwave generator (correspondingly dimensioned: r₁＝32mm，R₂＝37mm，R₃＝47mm，R₄＝37mm，R₅＝41mm，R₆＝36mm，R₇＝39mm，R₈＝49mm，L₁＝26mm，L₂＝31mm，L₃＝12mm)。

In particle simulation, when the diode voltage is 676kV and the current is 7.4kA, the highest microwave power output by C wave band is 1.5GW and the beam-wave action efficiency is 30% by adjusting the guiding magnetic field to be 1.5T; when the voltage of the diode is 669kV and the current is 7.5kA, the highest power of the microwave output in the X wave band is 2.1GW and the beam-wave action efficiency is 42% by adjusting the guiding magnetic field to be 0.7T. From the above results, the invention overcomes the defects of complicated regulation mode (mostly mechanical regulation of more than two structural parameters), narrow regulation bandwidth (regulation in wave band or frequency modulation across adjacent wave bands) and the like of the common frequency tuning high-power microwave source, can change the axial magnetic field only by changing the current supplied to the solenoid, realizes large interval frequency jump across C, X wave bands, and has important reference significance for designing the device.

Referring to fig. 3, it can be known that the drift section length has an influence on the output microwave beam-wave action efficiency, when the drift section length is 2.8-3.4cm, the C (under a 1.5T magnetic field) and X (under a 0.7T magnetic field) wave bands have higher-efficiency microwave outputs, and when the drift section length is 3.1cm, both the two wave bands reach the highest beam-wave action efficiency.

Referring to fig. 4, it can be seen that the radius of the drift region has an influence on the output microwave beam-wave efficiency, when the radius of the drift region is 3.7-4.3cm, the C (under a 1.5T magnetic field) and X (under a 0.7T magnetic field) wave bands have higher-efficiency microwave outputs, and when the radius of the drift region is 3.9cm, both wave bands reach the highest beam-wave efficiency.

Referring to fig. 5, it can be seen that the magnitude of the magnetic field has an influence on the beam-wave efficiency of the output microwave, and when the magnetic field is in the range of 1.30T to 2.05T, the microwave of the X band is suppressed, only the single-frequency oscillation of the microwave of the C band can be excited, and when the magnetic field is 1.5T, the highest beam-wave efficiency is achieved; when the magnetic field is 0.60-0.75T, the microwave of C wave band is inhibited, only the single-frequency oscillation of the microwave of X wave band can be excited, and when the magnetic field is 0.7T, the highest beam-wave action efficiency is achieved.

Referring to fig. 6, it can be known that high-power microwave oscillation in the C band is excited, the microwave starts oscillating in 8ns, is saturated after 30ns, and the saturated microwave power is 1.5 GW.

Referring to fig. 7, it can be known that high power microwave oscillation in the X band is excited, the microwave starts oscillating in 12ns, is saturated after 30ns, and the saturated microwave power is 2.1 GW.

Of course, in the preferred embodiment, other connection manners may be adopted between the components, and the device structure may also be processed by using other materials, which are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and any technical solutions that fall under the spirit of the present invention belong to the protection scope of the present invention.

It will be clear to a person skilled in the art that the scope of the present invention is not limited to the examples discussed in the foregoing, but that several amendments and modifications thereof are possible without deviating from the scope of the present invention as defined in the attached claims. While the invention has been illustrated and described in detail in the drawings and the description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the term "comprising" does not exclude other steps or elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims shall not be construed as limiting the scope of the invention.

The above-mentioned embodiment is only one of the preferred embodiments of the present invention, and should not be used to limit the scope of the present invention, but all the insubstantial modifications or changes made within the spirit and scope of the main design of the present invention, which still solve the technical problems consistent with the present invention, should be included in the scope of the present invention.