58results about How to "Adjust the resonant frequency" patented technology

The invented optical-fibre grating vibration sensor is characterized by that it utilizes a demodutation grating and a sensing grating and makes them be series-connected together, and respectively makes them be stuck on a main beam and an auxiliary beam, two beams are made of identical material and have identical heat expansion coefficient, so that their central wavelengths can be synchronously shifted with temperature, therefore they have automatic temperature compensation function so as to implement matching filter demodutation. Said invention utilizes the detection of light intensity change of sensing grating reflecting light to monitor the parameters of vibration frequency and vibration amplitude of monitored body, finally utilizes computer or single-chip computer to make analysis and processing of body vibration frequency spectrum.

The invention relates to a cavity-type film bulk acoustic resonator (FBAR), consisting of a silicon on insulator (SOI) substrate with a cavity and a piezoelectric thin film transducer arranged on the substrate. The FBAR is characterized in that the surface of the substratum silicon slice in the SOI substrate with the cavity is provided with a groove, substratum silicon slice and top-layer silicon are bonded to form a closed cavity structure; the upper of the top-layer silicon is provided with a transducer which is composed of a piezoelectric thin film and thin electrodes plated on the upper surface and the lower surface of the piezoelectric thin film; and a resonator can be tuned, and the thickness of the top-layer silicon can be regulated through controlling the etching time of the top-layer silicon on the upper of the cavity, thus the resonant frequency of the resonator can be regulated. As the preset cavity structure is used, in the invention, no sacrificial layer is needed, thus the chemical mechanical polishing process and the sacrificial layer release process in aboard patents and products, which are used for treating the sacrificial layer are not required; and meanwhile, in the invention, the advantages of small source parasitic capacitance, small drain parasitic capacitance, low voltage, low power consumption and the like of an SOI material are integrated, therefore, the FBAR can be compatible with an integrated circuit (IC), is easy to integrate, has simple process and is applicable to mass production.

The invention discloses a miniature dual polarized antenna suitable for WLAN, which comprises a metal radiation patch, a microstrip feed line, a first dielectric plate, a second dielectric plate and a grounding plate, wherein the metal radiation patch is arranged on the upper surface of the first dielectric plate; the microstrip feed line is arranged between the first dielectric plate and the second dielectric plate, and is etched in the center of two adjacent edges of the upper surface of the second dielectric plate; and the grounding plate is arranged on the lower surface of the second dielectric plate. The miniature dual polarized antenna has the advantages of high gain, wide band, low loss, low cost, compact structure, good radiation performance and the like, and satisfies the requirements of a WLAN communication network at 2.4 GHz frequency band.

The invention relates to a birdcage coil for a magnetic resonance imaging system and a tuning method thereof. The birdcage coil comprises an upper annular conductor, a lower annular conductor and a plurality of linear conductors which are distributed on a cylindrical surface, wherein the linear conductors are connected between the upper annular conductor and the lower annular conductor. A plurality of capacitors are connected in series in the upper annular conductor and the lower annular conductor. The whole or a part of the linear conductor is flexibly bendable and deformable. The distance between the upper annular conductor and the lower annular conductor is changed when the degree of bending deformation of the linear conductor is adjusted so that the resonant frequency of the birdcage coil is changed. The resonant frequency is adjusted by changing the position of a debugging ring. Thus, an expensive adjustable capacitor device is replaced so as to reduce the cost of the birdcage coil. The birdcage coil can be easily debugged at the installation site of the magnetic resonance system. The structure of the whole birdcage coil is adjusted synchronously and a large tuning range is achieved. The distribution of coil current and the uniformity of an RF magnetic field inside the coil are not influenced. The birdcage coil is stable in mechanical structure and can withstand high voltage.

The invention discloses a preset hollow cavity protection wall type film bulk acoustic wave resonator, and a preparation method. The film bulk acoustic wave resonator comprises an SOI substrate with apreset hollow cavity and a transducer stacking structure; the preset hollow cavity is formed by enclosing protection walls of side walls and a protection bottom at the bottom, and the protection walls and the protection bottom are used for ensuring that the SOI substrate is not excessively corroded; the transducer stacking structure is located on the SOI substrate and is opposite to the preset hollow cavity; and at least one release channel penetrating through the transducer stacking structure and communicating with the preset hollow cavity is arranged on the transducer stacking structure. According to the preset hollow cavity protection wall type film bulk acoustic wave resonator disclosed by the invention, the situation of insufficient corrosion and excessive corrosion of the preset hollow cavity in a corrosion process can be avoided, and the size and the shape of the preset hollow cavity can be accurately controlled, so that the effective preparation of the film bulk acoustic waveresonator is realized.

The invention relates to a GPS and Bluetooth double-frequency and micro-strip antenna. An E-shaped slot is opened on a radiation patch of the antenna and three shorting pins are inserted into a medium plate so as to achieve GPS and Bluetooth double-frequency operation. The three shorting pins in the medium plate connect the radiation patch and a grounding plate, which is equal to three shunt inductors. The resonance frequency of the micro-strip antenna can be adjusted by changing the position of the shorting pins and at the same time, the shorting pins can miniaturize the micro-strip antenna. The invention well achieves GPS and Bluetooth double-frequency operation and can be widely applied in the field of wireless telecommunication technology.

The invention provides a high-frequency insulation withstand voltage tester. The high-frequency insulation withstand voltage tester comprises a single-phase AC voltage regulator (1), a single-phase full-bridge uncontrolled rectifying circuit (2), a filter capacitor (3), a single-phase full-bridge inverter (4), a control system (5), an adjustable inductor (6), an adjustable capacitor (7) and a high-frequency high-voltage transformer (8). A test sample is connected to the output end of the high-frequency high-voltage transformer (8); a series resonance circuit composed of the adjustable inductor (6) and the adjustable capacitor (7) is enabled to work in the resonant states of different frequencies by changing the frequency of a square wave excitation signal output by the inverter, and then a high-frequency sinusoidal waveform can be generated at the input end of the high-frequency high-voltage transformer, and therefore, a frequency-adjustable high-frequency sinusoidal signal can be obtained at the output end of the transformer; the regulation of the amplitude of the output voltage of the tester can be realized by adjusting the output voltage of the single-phase AC voltage regulator. Finally, simultaneously adjustable output frequency and voltage of the tester are realized. The high-frequency insulation withstand voltage tester can be applied to the withstand voltage tests of insulating materials or equipment different in frequency and voltage grade.

The invention discloses a bi-waveband high-wave-transmittance metasurface which comprises structural units arranged in an array, wherein each structural unit comprises two opposite dielectric substrates, and a metal folding line between the two dielectric substrates. The metal folding line is etched in the middle of the dielectric substrates. The large-angle high-wave-transmittance metasurface has the advantages of simple structure, easy processing, high transmissibility in large incident angle, and bi-waveband transmission property. When the incident angle is large, the bi-waveband high-wave-transmittance metasurface realizes high transmission between two wavebands of Ku and Ka, and has total reflection characteristic in the X wave band. Combination of two functions is realized.

The invention provides a film bulk acoustic resonator with passivation layers and a preparation method thereof. The film bulk acoustic resonator comprises a substrate, a piezoelectric layer, a bottom electrode, a top electrode, a first passivation layer and a second passivation layer, the piezoelectric layer is arranged above the substrate, an air cavity is arranged between the piezoelectric layer and the substrate, the bottom electrode is arranged between the piezoelectric layer and the substrate, and the top electrode is arranged above the piezoelectric layer; the first passivation layer completely covers the top electrode and the piezoelectric layer, and the second passivation layer is located above the first passivation layer and completely covers the first passivation layer. The air cavity is adopted, and an interface of metal and air is formed between the substrate and the oscillation area of the resonator, so that sound waves can be limited in an oscillation pile, and the mechanical strength of the resonator is improved; through the cooperation of the first passivation layer and the second passivation layer, the resonator can be effectively isolated from the external environment, the temperature drift coefficient of the resonator is reduced, and the resonant frequency of the resonator can be sensitively adjusted by cutting the thickness of the second passivation layer.

The invention discloses a signal processing method and electronic equipment. The method comprises steps of receiving a first instruction, wherein the first instruction is an instruction for indicating support of a second frequency range, and the center frequency of the second frequency range is different from that of a first frequency range; and responding to the first instruction, and controlling a resonance unit for adjusting self impedance, so that an antenna unit is enabled to resonate with the center frequency of the second frequency range, wherein the self impedance of the resonance unit presents inductance characteristics. The invention can support the antenna unit for working at multiple frequency ranges, and the radiation performance of the antenna unit at each frequency range is ensured.

The invention relates to a digital television transmitting antenna based on an E-shaped patch. The digital television transmitting antenna comprises a formation plate, the E-shaped patch, a rectangular parasitic patch, an input connector and a retaining screw, wherein the rectangular parasitic patch, the E-shaped patch and the formation plate are orderly arranged in parallel from top to bottom to form a main structure of a stacked antenna; the E-shaped patch is provided with two symmetric rectangular gaps, and the length of a middle wing is smaller than that of two sides; an outer conductor of the input connector is fixed on the formation plate, and an inner conductor of the input connector penetrates through the formation plate and is connected to the E-shaped patch to feed; the rectangular parasitic patch at the upper layer is coupled by the E-shaped patch to feed. The digital television transmitting antenna based on the E-shaped patch provided by the invention satisfies the use requirement of a terrestrial television broadcasting transmitting system by adopting a multi-resonator technology to improve the impedance bandwidth and power handling of antennas; the invention has the characteristics of being wide in working band, high in gain, small in input standing-wave ratio, high in power handling, simple in processing, convenient in debugging and the like, and is applicable to a terrestrial television transmitting antenna system of a decimeter wave band.

The invention relates to a resonant cavity which comprises a cavity body, a harmonic oscillator arranged in the cavity body and a tuning device arranged on the cavity body and extending into the cavity body, and the length of the tuning device extending into the cavity is adjustable. The harmonic oscillator comprises at least one piece of metamaterial. A portion of the tuning device arranged in the cavity body is provided with at least one piece of metamaterial. According to the technical scheme, by changing the length of the tuning device in the cavity body, resonant frequency of the resonant cavity can be changed.

A microstrip antenna includes: a radiation sheet; a grounding plate parallel to the radiation sheet; a short-circuit sheet conductively connected with the radiation sheet and the grounding plate; and a feed sheet positioned between the radiation sheet and the grounding plate; wherein the radiation sheet is provided with a slit so that the radiation sheet is U-shaped as a whole, and the U-shapedradiation sheet comprises two sub-sheets forming two arms of the U-shaped radiation sheet and a connecting part forming the bottom edge of the U-shaped radiation sheet; a feed source is arranged in the slit, one of a positive electrode and a negative electrode of the feed source is electrically connected with the connecting part, and the other one of the positive electrode and the negative electrode of the feed source is electrically connected with the feed sheet through a feed line; wherein the bottom side of the feed sheet is arranged to cling to the grounding plate and is separated from thegrounding plate through an insulating film, and the thickness of the insulating film is far less than 1/4 wavelength corresponding to the resonant frequency of the microstrip antenna. The microstripantenna provided by the invention is easy to realize mass production and keep consistent performance, has good metal resistance, is easy to adjust, and can be adapted to different frequency band requirements of different countries and regions in a simple manner.

The invention discloses a piezoelectric loudspeaker which comprises a shell which forms an external frame of the piezoelectric loudspeaker, and a sound production hole is formed on the shell. The piezoelectric loudspeaker further comprises a sound production part, a transmission part and a vibration part. The sound production part comprises a vibrating diaphragm arranged corresponding to the sound production hole; the transmission part comprises a support and a transmission plate, and the vibrating diaphragm, the transmission plate and the support are sequentially combined, wherein the transmission plate is combined with one side of the vibrating diaphragm in an airtight mode, and the one side of the vibrating diaphragm is away from the sound production hole; the vibration part comprises piezoelectric pieces and a plurality of supporting pieces, wherein the piezoelectric pieces are used for electrically connecting an external circuit, the plurality of supporting pieces are independently arranged, and the piezoelectric pieces are correspondingly arranged on the supporting pieces; and the supporting pieces are arranged inside the shell in a hanging mode, one ends of the supporting pieces are fixed on the shell, and the other ends of the supporting pieces are fixed on the support. The piezoelectric loudspeaker has the advantages of being good in acoustic performance.

The invention provides a vibration motor. The vibration motor includes a shell body having an internal cavity, a magnetic vibrator and a magnetic component driving the vibrator to vibrate, wherein thevibrator and the magnetic component are respectively accommodated in an internal cavity of the shell body. A first wire coil is fixed on the shell body, a second wire coil is fixed on the magnetic component, an alternating current is applied on the first wire coil, the vibrator is driven to vibrate along a direction of the internal cavity of the shell body, an adjustable current is applied on thesecond wire coil, the magnetic field of the magnetic component is repelled from the magnetic field of the vibrator, and a restoring force for rebound is provided for the vibrator to enable the vibrator to reciprocate in the inner cavity of the shell body; the size of a magnetic field generated via the magnetic component is adjusted to change the magnitude of the restoring force generated via themagnetic component, and thus resonant frequency is adjusted when the vibrator vibrates. The vibration motor disclosed in the invention can be used for adjusting the resonant frequency, and the vibration motor is enabled to have response which is high enough in a wide frequency band scope.

A surface mount antenna easily manufactured includes a substrate and a radiation electrode (having a predetermined resonance frequency) disposed on the substrate. An electrode is formed to cover four continuously connected surfaces including the front surface, the front end surface, the rear surface and the rear end surface of each substrate. Then, a dicer is used to cut a slit on the radiation electrode formed on the surface of the dielectric substrate. Here, the slit is arranged in a direction intersecting a direction alpha connecting the two end surfaces. Subsequently, the dielectric substrate is cut into a plurality of portions along the direction alpha, thus producing a plurality of surface mount antennas each including a substantially rectangular substrate and a radiation electrode formed essentially surrounding an outer circumference of the substrate. In this way, it is possible to produce a plurality of surface mount antennas in only one operation. Since each radiation electrode has a very simple shape, and since a dicer can be used to perform a high precision processing, it is easy to form each radiation electrode having a desired resonance frequency, by using a dicer to perform a cutting treatment to process the slit.

The invention relates to a broadband motor, which comprises a shell, at least one coil, a magnetic assembly and a connecting piece, and the magnetic assembly is arranged in the shell; the coil is wound outside or inside the shell, the magnetic assembly comprises a first magnetic piece, a second magnetic piece, a third magnetic piece and a fourth magnetic piece, the left side and the right side ofthe connecting piece are respectively provided with the first magnetic piece and the second magnetic piece, and the connecting piece, the first magnetic piece and the second magnetic piece form an oscillator assembly; a third magnetic piece is arranged on the side, away from the oscillator assembly, of the first magnetic piece, and a fourth magnetic piece is arranged on the side, away from the oscillator assembly, of the second magnetic piece. The magnetic field of the motor vibrator assembly and the magnetic field of the motor shell repel each other to achieve force balance, so that the vibrator is suspended in the motor, the vibrator assembly has repulsive force in the motor shell and in the directions of the two ends, the force in the directions of the two ends of the vibrator assemblyis balanced, and the polarity of the magnetic field of the structure can be completely reversed.

The invention discloses a novel analog low-pass filter circuit and a design method, and relates to the technical field of analog low-pass filters. The method comprises the following steps: step S01, determining passband cut-off frequency and characteristic impedance of a designed low-pass filter, calculating various parameters of a central circuit, and selecting parameter values close to calculated values; s02, determining the number of frequency points needing to be suppressed and corresponding frequency values, calculating various parameters of each stop-band suppression circuit, and selecting parameter values close to the calculated values; and S03, detecting the suppression effect of the low-pass filter. If the suppression is not satisfied, returning to the step S02, adjusting the related parameters until the suppression is satisfied, and finally completing the design of the low-pass filter. Low-pass filtering is realized by utilizing the characteristic that the impedance of the LC parallel resonance circuit is infinite, strict function constraint does not need to be obeyed, the design difficulty is reduced, and the efficiency is improved.

The invention relates to a filter which comprises a shell, a first tubular object, a resonator and a second tubular object. The shell comprises a bottom plate, side plates and a cover plate, and a through hole is formed in the cover plate. By changing the volume of the liquid in the first tubular object, the dielectric constant in the first tubular object is changed, so that the equivalent wavelength in the filter is changed, and the resonant frequency in the filter is adjusted. By changing the volume of the liquid in the second tubular object, the dielectric constant in the second tubular object is changed, so that the coupling strength in the filter is changed, the resonant frequency in the filter is separated, and the fractional bandwidth of the filter is kept unchanged under the condition that the resonant frequency is changed. The filter can be applied to different scenes by adjusting the resonant frequency in the filter, so that the applicability of the filter is improved.

The invention relates to a broadband motor, and the motor comprises a shell, a magnetic assembly, an elastic mechanism, a mass block and a connecting part; the motor also comprises a coil assembly, and the coil assembly comprises a plurality of coils; the magnetic assembly is arranged in the shell, and the coils surround the periphery of the connecting part. The magnetic assembly comprises a firstmagnetic part, a second magnetic part, a third magnetic part, a fourth magnetic part and an internal magnetic part; the connecting part, the mass block, the first magnetic part, the second magnetic part and the internal magnetic part form an oscillator assembly, and the mass block, the first magnetic part, the second magnetic part and the internal magnetic part are connected through the connecting part. The magnetic field of the motor vibrator assembly and the magnetic field of the motor shell repel each other to achieve force balance, so the vibrator is suspended in the motor, the vibrator assembly has a repulsive force in the motor shell and in the directions of the two ends, the force in the directions of the two ends of the vibrator assembly is balanced, and the polarity of the magnetic field of the structure can be completely reversed.