62 results about "Parasitic mode" patented technology

The MRI rf coil known as the balanced high-pass-weighted hybrid birdcage is modified to obtain two homogeneous degenerate resonances, capable of generating circular polarization at widely separated frequencies, by including inductors in parallel with the ring (high-pass) tuning capacitors such that their isolated parallel resonant frequency is greater than the desired low-frequency (LF) homogeneous resonance and not greater than 10% more than the desired high-frequency (HF) homogeneous resonance. The coil is advantageous for the frequency-diameter product range of 10 to 60 MHz-m. The coil is preferably balanced at both frequencies such that the electric potentials vanish on the central axial plane at both the LF and HF homogeneous modes. Additional parasitic-mode-shifting reactive elements, either capacitors or inductors, may be added between adjacent rungs near their ends, and the rungs may each consist of two parallel bands shorted together at their ends, as in the Crozier birdcage. Note that a high-pass-weighted hybrid birdcage is defined as a hybrid birdcage in which the reactance of the rung series capacitors is significantly less than the reactance of the ring series capacitors.

The invention discloses a short millimeter wave stacked type cylindrical cavity filter for restraining a parasitic mode, and belongs to the technical field of thz devices. The short millimeter wave stacked type cylindrical cavity filter adopts a layered structure to realize stacking a plurality of cylindrical resonant cavities; the size of a coupling window is controlled by controlling the location offset of cylindrical cavities, and the coupling electromagnetic energy size is controlled, so that a coupling coefficient and an external quality factor are controlled; the diameters and the heights (namely the thickness of the layer) of the cylindrical cavities are controlled to control the resonant frequency, wherein a resonant mode is selected as a TE111 mode. The parasitic mode close to the symmetrical restraining frequency with respect to the centre H surface is utilized to improve the stop band frequency, and the optimizing rate is increased by multiple times. Relative to the high requirements of a rectangular waveguide cavity with millimeter and sub-millimeter dimension, the stacked type cylindrical cavity greatly reduces the difficulties of precise mechanical processing process; under the same processing precision condition, the filter frequency realized by the structure is higher than that of the rectangular cavity filter.

The invention belongs to the technical field of resonators and discloses a two-dimensional Lamb wave resonator which is characterized in that a first electrode array and a second electrode array are arranged on the upper surface and the lower surface of a piezoelectric layer, each of the first electrode array and the second electrode array comprises a plurality of positive electrode columns and first negative electrode columns which are arranged along a first direction and a second direction, and the positive electrode columns and the negative electrode columns are alternately arranged; the positive electrode columns comprise a plurality of positive electrodes, every two adjacent positive electrodes are connected through a bridge, the negative electrode columns comprise a plurality of negative electrodes, and every two adjacent negative electrodes are connected through a bridge; the first direction is perpendicular to the second direction; the orthographic projection of any one of thepositive electrodes in the first electrode array to the second electrode array covers one of the negative electrodes, and the orthographic projection of any one of the negative electrodes in the firstelectrode array to the second electrode array covers one of the positive electrodes. The two-dimensional Lamb wave resonator provided by the invention can improve the electromechanical coupling coefficient of the resonator and reduce the parasitic modes.

A novel laser cavity structure is disclosed which pertains to laser resonator geometries possessing circular symmetry, such as in the case of disk or spherical lasers. The disclosed invention utilizes a very-high finesse Bragg reflector (VHF-BR) thin film reflectors of many layer pairs of very small refractive index difference, the VHF-BR deposited on a surface of revolution, thereby forming an optical cavity. These dielectric reflectors are disposed in such a way as to allow selection of preferred low order modes and suppression of parasitic modes while allowing a high cavity Q factor for preferred modes. The invention disclosed, in its preferred embodiments, is seen as particularly useful in applications requiring high efficiency in the production and coupling of coherent radiation. This is accomplished in a cavity design that is relatively compact and economical. Of particular novelty is the combination of the disclosed cavity design with polymer multilayers. The ability to deposit an unusually large number of polymer thin films without loss of specularity, while maintaining very low extinction, renders the disclosed polymer-based cavity particularly well-suited for higher mode discrimination, more rugged and light-weight cavities, as well as economical fabrication.

A radio frequency resonator structure disclosed by the invention includes a piezoelectric layer, and a certain amount of top interdigital electrodes and bottom interdigital electrodes respectively configured on the upper and lower surfaces of the piezoelectric layer, wherein troughs along the length direction of the top interdigital electrodes are respectively disposed at the positions between adjacent top interdigital electrodes on the upper surface of the piezoelectric layer; and at the same time, troughs along the length direction of the bottom interdigital electrodes are respectively disposed at the positions between adjacent bottom interdigital electrodes on the lower surface of the piezoelectric layer. By disposing troughs along the length direction of the interdigital electrodes onthe piezoelectric layer between adjacent interdigital electrodes, the invention obviously eliminates the parasitic mode of the resonator and improves the electromechanical coupling factor of the resonator, and is easy to implement and low in implementation cost.

Operation of a planar resonator gyroscope with in-plane parasitic modes of vibration to obtain improved performance is disclosed. A planar resonator gyroscope, such as a disc resonator gyroscope, may be operated with embedded electrodes. The embedded electrodes may be disposed adjacent to the planar resonator and proximate to one or more anti-nodes of a parasitic vibration mode. A sensed amplitude of the parasitic mode is applied in differential signals used to operate the gyroscope. A feedback controller for damping the parasitic mode applies a drive voltage generated from the proportional voltage to one or more drive electrodes adjacent to the planar resonator disposed proximate to one or more anti-nodes of the parasitic vibration mode of the planar resonator. Parasitic in-plane modes may be thus damped in operating the gyroscope with active damping applied through an analog operational amplifier or digital feedback.

The invention discloses an acoustic resonator, comprising a substrate, a sound isolator formed in or above the substrate, a first electrode formed on the sound isolator, a piezoelectric layer formed on the first electrode, a second electrode formed on the piezoelectric layer, and a liner formed on the piezoelectric layer, wherein one end of an edge of the sound isolator is defined as a first boundary while the other end is defined as a second boundary, one end of an edge of the second electrode is defined as a first boundary while the other end is defined as a second boundary, and the edge of the second electrode is positioned at inner side of the edge of the sound isolator, and the liner surrounds the edge of the second electrode and is positioned at the inner side of the edge of the sound isolator. The acoustic resonator disclosed by the invention is simple in structure and easy for implementation and has a higher quantization parameter (Qp). Furthermore, the acoustic resonator cannot damage the quality standard (Qs) and an effective electromechanical coupling coefficient and can avoid a parasitic mode.

The invention discloses a surface acoustic wave device, which divides the interdigital transducer bus bars into a gap region, an edge region and an intermediate region, and the directions from any busbar to the two bus bars are the gap region, the edge region and the intermediate region in turn. By arranging the hill layer covered by the electrode between the piezoelectric substrate and the electrode, the acoustic wave velocity in the gap region is larger than the acoustic wave velocity in the intermediate region, and the acoustic wave velocity in the intermediate region is larger than the acoustic wave velocity in the edge region. The waveform propagated between the interdigital transducers can be filtered into the piston waveform by the above arrangement, thereby filtering the remainingwaveforms of the non-piston waveform, thereby effectively reducing the parasitic mode of the surface acoustic wave device, and enabling the surface acoustic wave device to have a higher quality factor. The invention also provides a preparation method of a surface acoustic wave device, and the surface acoustic wave device prepared by the method also has the beneficial effects.

A optoelectronic device is disclosed containing at least one multilayer interference reflector, having at least two periodicities in the refractive index. At least one of the periodicities, or quasi-periodicities, prohibits the light emission in a range of angles tilted with respect to the intentionally selected direction, for example, in the direction perpendicular to the layer planes, preventing the emission of light in the optical modes propagating in a certain interval of angles, dangerous for the device, and thus reducing the effect of parasitic modes on the device performance. A light generating element emitting light in a certain wavelength range is preferably introduced in one of the layers. The light is then channeled into the required angle range. The device can additionally contain a cavity. A second periodicity of the refractive index is preferably selected to ensure a high reflectivity in the vertical direction enabling advanced vertical cavity surface-emitting lasers.In other embodiments a double periodicity is selected to ensure a high reflectivity of light in a direction tilted with respect to the vertical direction. An optoelectronic device having a multilayer interference reflector with two periodicities can operate as a light-emitting diode, a superluminescence light-emitting diode, a laser diode, a single photon emitter, or an emitter of entangled photons.

The invention provides a wideband coaxial resonant cavity. The wideband coaxial resonant cavity comprises an outer conductor, an inner conductor, an upper end cover and a lower end cover, wherein the inner conductor is coaxially arranged in the outer conductor, the upper end cover is arranged above the outer conductor, the lower end cover is arranged at the bottom of the outer conductor, the inner conductor, the outer conductor, the upper end cover and the lower end cover form a coaxial resonant cavity, two through holes are symmetrically formed in a lower end of a side wall of the outer conductor around a central axis of the resonant cavity, coupling rings are inserted to the through holes, a plurality of groove bodies are circumferentially and uniformly arranged on an outer surface of the side wall of the outer conductor and vertically extend towards the center of the resonant cavity, the depth of each groove body is smaller than the thickness of the side wall of the outer conductor, a gap is arranged in each groove body and extends to an inner wall of the outer conductor, the width of the gap is smaller than that of the groove body, and the interior of the groove body is filled with a wave absorption material covering the gap. With the adoption of the abovementioned scheme, a large of parasitic modes can be effectively suppressed, a main mode is easier to recognize, particularly, the effect is more obvious in a relatively high frequency range, the frequency spectrum of a relatively pure TEM00p mode in a relatively wide frequency band range of 0.6-13.5GHz can be finally obtained, and more than ten discrete frequency points are covered.

The utility model has discloses a coupling output structure for traveling wave tube amplifiers, which comprises an input port and an output port; wherein, the radius of the output port is bigger than that of the input port, a first grade gradually variable circle waveguide and an Nth rank gradually variable circle waveguide are cascaded between the input port and the output port. The utility model adopts the double-segment correcting Duelfer-Chebyshev gradually variable circle waveguide cascade connection or a transition circle waveguide cascaded in the central section of the double-segment correcting duelfer-chebyshev gradually variable circle waveguide. The utility model has the advantages of resolving the problems in prior art , such as large size, high reflection coefficient of the input port and weak capacity of parasitic mode restraint; when the coupling output structure is applied to traveling wave tube amplifiers, positive effects can be obtained, , which are of great practical significance for developing the high power microwave sources applied in long ranged radars and electronic warfare technology.

The invention discloses a confocal waveguide broadband input coupling device, and relates to the technical field of microwave and millimeter wave devices, specifically a novel confocal waveguide gyro-TWT (standing wave tube) broadband input coupling device, wherein the device can be used for a gyro-TWT at a millimeter wave band and terahertz wave band. There are also many parasitic modes in a confocal waveguide broadband input coupling system, thereby causing the decrease of the coupling efficiency. Therefore, the device inhibits the parasitic modes through changing the boundary conditions, and enables the more power inputted by standard waveguides to be coupled to the power in a working mode. An opening surface of the confocal waveguide broadband input coupling system is sealed, and the sealed surface is slotted, thereby changing the boundary conditions, inhibiting the parasitic modes, enabling the coupling efficiency of the working mode to be higher, and enabling the coupling bandwidth to be greater.

The invention discloses a culturing method for transplanting dendrobium officinale to old fruit trees in a parasitic mode and belongs to the technical field of planting plants. The culturing method comprises the steps of culturing seedling tissues, hardening the tissue culture seedlings and transplanting the seedlings to the old fruit trees in the parasitic mode for culturing. The step of hardening the tissue culture seedlings comprises the steps of selecting the bottled tissue culture seedlings, preparing matrixes for culturing the young seedlings, applying fertilizer, carrying out field planting and carrying out field planting management; the step of transplanting the seedlings to the old fruit trees in the parasitic mode comprises the steps of selecting the young dendrobium officinale seedlings, the old host fruit trees and culturing fields of the old host fruit trees, adopting a transplanting method and carrying out culture management. The culturing method solves the prevailing problems that due to the special natural growing environment of the dendrobium officinale, manual culturing is difficult to carry out, the survival rate of transplanting is low, the product quality is not ideal and the planting cost is high, land and space are fully utilized, operation and management are easy to carry out, resource materials are saved, manpower and material resources are saved, and good economic benefits and social benefits are achieved.

The invention provides a hybrid acoustic wave resonator of a bulk acoustic wave resonator and a surface acoustic wave resonator, which comprises a base, a bottom electrode, a piezoelectric layer and atop electrode which are sequentially arranged from bottom to top; a first reflecting layer is formed between the substrate and the bottom electrode so as to form a bulk acoustic wave resonator; an interdigital electrode is formed on the same piezoelectric layer; and a second reflection layer is formed between the substrate and the piezoelectric layer so as to form a surface acoustic wave resonator. According to hybrid acoustic wave resonator in the invention, through an integration process, the top electrode of the bulk acoustic wave resonator and the interdigital electrode of the surface acoustic wave resonator are directly formed on the same piezoelectric layer; the process flow is reduced; the phenomenon that the piezoelectric substrate is broken or severely warped in the original process is avoided; meanwhile, the parameters of the surface acoustic wave resonator can be adjusted so that the effects of restraining the transverse parasitic mode of the bulk acoustic wave resonator and inhibiting sound wave frequency doubling are achieved.

The MRI rf coil known as the balanced high-pass-weighted hybrid birdcage is modified to obtain two homogeneous degenerate resonances, capable of generating circular polarization at widely separated frequencies, by including inductors in parallel with the ring (high-pass) tuning capacitors such that their isolated parallel resonant frequency is greater than the desired low-frequency (LF) homogeneous resonance and not greater than 10% more than the desired high-frequency (HF) homogeneous resonance. The coil is advantageous for the frequency-diameter product range of 10 to 60 MHz-m. The coil is preferably balanced at both frequencies such that the electric potentials vanish on the central axial plane at both the LF and HF homogeneous modes. Additional parasitic-mode-shifting reactive elements, either capacitors or inductors, may be added between adjacent rungs near their ends, and the rungs may each consist of two parallel bands shorted together at their ends, as in the Crozier birdcage. Note that a high-pass-weighted hybrid birdcage is defined as a hybrid birdcage in which the reactance of the rung series capacitors is significantly less than the reactance of the ring series capacitors.

The invention provides a waveguide mode exciting device which comprises a first mode conversion assembly and a second mode conversion assembly. The first mode conversion assembly is used for converting the mode of millimeter waves from a TE 10 fundamental mode to a circular waveguide TE61 mode, and the second mode conversion assembly is used for being communicated with the first mode conversion assembly and converting the mode of the millimeter waves from the circular waveguide TE61 mode to the circular waveguide TE62 mode. According to the waveguide mode exciting device, by means of a mode conversion chain of converting the rectangular waveguide TE10 mode into the circular waveguide TE62 mode, the high-purity target mode output is obtained, a parasitic mode is effectively restrained, and the obtained high-purity target mode can be used for cold measuring of a gyrotron interaction circuit and a standard light mode converter system.

The present invention discloses a curved waveguide mode converter based on surface plosmon polaritons and an implementation method thereof. Gratings with the uniform depth are respectively arranged at the inner concave surface and the outer concave surface of an arc waveguide, the inner walls of two sections of straight waveguides connected with the inner concave surface and the outer concave surface are respectively provided with gratings with gradually varied depths, when electromagnetic waves pass through the arc waveguide, a surface wave mode is aroused at the gratings with the uniform depth so as to constrain the electromagnetic waves at the surface, and the grating with gradually varied depths can realizes the wave vector matching between the waveguide mode and the surface wave mode. The curved waveguide mode converter based on the surface plosmon polaritons and the implementation method thereof are compact in structure with no need for other transition parts; compared to a traditional method, through adoption of the lithography technology, the processing is easy, the curved waveguide mode converter based on the surface plosmon polaritons and the implementation method thereof change the depths of the gratings and is also taken as a curved waveguide for usage; the curved waveguide is big in curvature and small in occupied space compared to the curved waveguide having the same functions in the prior art; and moreover, the method provided by the invention is high in mode conversion efficiency can reduce the reflection and other parasitic modes to the lowest.

The invention, which belongs to the technical field of high-power millimeter-wave devices, discloses a broadband high-power millimeter-wave over-mode waveguide TE01 directional coupler comprising an over-mode quadrupole main waveguide, an input transition section, an output transaction section, and an auxiliary waveguide communicated with a protrusion part of the over-mode quadrupole main waveguide by one row of circular coupling holes. The input transition section and the output transaction section are arranged at the two ends of the main waveguide symmetrically. According to the invention, on the basis of the over-mode quadrupole waveguide structure, the power capacity is large and output characteristics of stable coupling and high directivity are realized in a broadband range; the modespacing is large in the quadrupole waveguide, so that the directional coupler has high mode selectivity and thus influences by other parasitic modes are eliminated; and on the basis of the quadrupolewaveguide structure, the high-directivity index is realized and the directional coupler has the anti-standing wave characteristic.

The invention discloses a strong field mode filter for only reserving a TE0n mode. The strong field mode filter comprises an input flange and an output flange for connection; a barrel-shaped parasiticmode absorption part is connected between the two flanges; a heat dissipation assembly is arranged on the outer wall of the parasitic mode absorption part in the axial direction; the two ends of theheat dissipation assembly are connected to the two flanges; the heat dissipation assembly comprises a shell arranged on the outer surface of the parasitic mode absorption part and a heat dissipation part arranged outside the shell; and the heat dissipation assembly, the flanges and the parasitic mode absorption part form an overall regular hollow cylinder. The strong field mode filter is based onthe dielectric loaded loss principle, however, electrical resistivity anisotropic materials are adopted to realize filtering of all non-TE0n modes, so that the strong field mode filter has the characteristics of high power capacity and capability of filtering all non-TE0n mode parasitic modes.

The invention discloses a rectangular waveguide TE10 mode-circular waveguide TE01 mode converter, which belongs to the technical field of microwave and millimeter wave transmission devices. The rectangular waveguide TE10 mode-circular waveguide TE01 mode converter comprises a rectangular waveguide power division network, a quadrupole waveguide TE01 mode conversion structure and a quadrupole waveguide-circular waveguide transition structure, wherein the TE10 mode inputted by a standard rectangular waveguide is divided into four equal-amplitude TE10 modes through a rectangular waveguide power divider network, the four TE10 modes are injected to the quadrupole waveguide TE01 mode conversion structure at the same time to excite corresponding TE01 modes, and finally, the TE01 modes in the quadrupole waveguide TE01 mode conversion structure gradually change to circular waveguide TE01 modes through the quadrupole waveguide-circular waveguide transition structure, and conversion from the rectangular waveguide TE10 mode to the circular waveguide TE01 mode is realized. Generation of a parasitic mode can be effectively suppressed, the whole mode converter has the advantages of high efficiency, high purity and wide band, and besides, the waveguide mode converter has a compact and simple structure, processing and assembling are easy, and the engineering practicality is good.

The invention discloses a system and method for testing a multi-frequency point material. By virtue of the advantage that a main mode of a coaxial opening type resonant cavity is not interfered by a parasitic mode, a dielectric constant of a tested material is calculated through the deviation of a resonant frequency point, and the rough position of the deviated resonant frequency point in a relatively high frequency band, so that the range of the testing frequency is extended. The method disclosed by the invention is suitable for measuring most materials and is particularly suitable for measuring the materials such as quartz, polytetrafluoroethylene, sapphires, corundum and ceramic with dielectric properties barely changed along the frequency.

The invention discloses a distribution attenuating confocal waveguide gyrotron travelling wave tube high frequency system and belongs to the technical field of microwave, millimeter wave and terahertz devices. The structure is composed of confocal waveguides which are symmetrical up and down. Side faces of the confocal waveguides are opened. Mirror surface curvatures of the confocal waveguides are consistent. Each confocal waveguide comprises an input uniform section, an input transition section, an interaction section, an output transition section and an output uniform section. According to the structure, a backward wave oscillator circuit of a parasitic mode is cut off through adoption of the interaction sections of the confocal waveguides with very narrow mirror surface widths, and moreover, it is ensured that the interaction sections are long enough, thereby realizing relatively high linear gain. Diffraction losses of a high frequency field after amplification are reduced by increasing the mirror surface widths of the output uniform sections, so the output power and total efficiency of a working mode are improved.

The invention discloses a method for artificially cultivating xuefengensis. According to the method, Ophiocordyceps xuefengensis is arranged on insect larva bodies of a furuncle bat moth family in a parasitic mode by T. C. Wen, J. C. Kang and R. C. Zhu. Plant folium isatidis is a host, a pleasant environment is built, and the xuefengensis cultivated artificially is obtained. The method for artificially cultivating the xuefengensis has the advantages that a cycle for cultivating the xuefengensis artificially only needs 1.5-3 months, and the cycle is shortened by more than 12 months in a natural state; the yield of the artificial xuefengensis is 7-10 times that of the artificial xuefengensis in a natural state; the quality of the artificial xuefengensis is improved, adenosine, mannitol, cordycepin, amino acid and the like in the artificial xuefengensis conform to the standards of cordyceps sinensis, and the content of the cordycepic acid is higher than that of the cordyceps sinensis.

A method is disclosed for improving the functionality of a semiconductor diode laser with an extended vertical waveguide, wherein the active medium is located close to the top cladding layer of the waveguide, and the laser aims to emit light in a narrow beam with high brightness and / or to operate in the wavelength-stabilized regime. The goal is to suppress parasitic optical modes localized close to the top cladding layer of the waveguide. Unpumped sections and groves perpendicular to the stripe serve to suppress these parasitic modes. Deep (preferably a few tens of micrometers) groves parallel to the stripe suppress parasitic emission of light and the feedback in the closed lateral modes. In a tilted wave laser the longitudinal resonator can be preferably configured to have a selected length to ensure closed loops formed in the longitudinal direction by the tilted wave.

The invention discloses a hybrid Balun filter. The hybrid Balun filter comprises a metal ground plate, a metal enclosure, a coaxial resonator, a first dielectric resonator and a second dielectric resonator, wherein the dominant mode frequencies of the coaxial resonator, the first dielectric resonator and the second dielectric resonator are identical; a first metal separation plate with a coupling window is arranged between the first dielectric resonator and the coaxial resonator; a second metal separation plate with a coupling window is arranged between the second dielectric resonator and the coaxial resonator; the first dielectric resonator and the second dielectric resonator are totally identical and are symmetrically distributed at two sides of the coaxial resonator; the axes of the first dielectric resonator and the second dielectric resonator are perpendicular to the metal ground plate; and the axis of the coaxial resonator is parallel to the metal ground plate. According to the hybrid Balun filter provided by the embodiments of the present invention, the coaxial resonator and the dielectric resonators are combined, so that most parasitic modes of the dielectric resonators can be suppressed, and therefore, the Balun filter is wider in differential-mode stop band, lower in insertion loss, and good in output balance.

A multi-channel mode converter operating with a series of TE or TM mode electromagnetic wave includes a plurality of coaxial waveguides arranged in overlay configuration. By controlling radius ratio and the number of coupling aperture of each coaxial waveguide, high power and high purity of operating mode of electromagnetic wave can be obtained and the major parasitic mode of electromagnetic wave can be suppressed, so as to avoid crosstalk between coaxial waveguides. A rotary joint including the above-mentioned mode converter with multi-channel is also disclosed.

The invention provides a broadband dielectric resonator. The broadband dielectric resonator comprises an upper plate and a lower plate of the resonator, a dielectric material to be detected and a coupling ring, wherein the upper plate and the lower plate of the resonator and the dielectric material to be detected form a dielectric resonance part; the upper plate and the lower plate of the resonator are manufactured from a hard dielectric substrate; a metal coating is arranged on the surface, facing the dielectric material to be detected, of the hard dielectric substrate, and a gap structure iscarved in the metal coating. Through the adoption of the scheme, most parasitic modes can be inhibited effectively, so that the operating mode is identified more easily, particularly in high band ofthe operating mode, the inhibitory effect for parasitic modes is more obvious, and finally a relatively pure TE0np mode frequency spectrum can be obtained in a wide frequency range.

The invention provides a liftable parasitic seawater pump frame, which mainly includes a guide protection pipe, a water lift pipe, a lift rack, a submersible pump, a seawater hose, a lift unit, a guide support arm and the like. The guide protection pipe is parasitic and fixed on the platform legs, and the lifting pipe is installed in the guide protection pipe and can slide along the guide protection pipe, which reduces the dependence on the stiffness of the seawater pump frame itself. At the same time, the lifting movement of the lifting pipe and the seawater pump is realized through the meshing of the lifting unit and the rack mounted on the lifting pipe. It has the characteristics of compact structure, light weight, flexible lifting and convenient operation. It reduces the dependence on the rigidity of the seawater pump frame under the marine environment conditions, and adapts to the water intake requirements under the large air gap operating conditions of the platform.