25 results about "Mode excitation" patented technology

The invention belongs to the technical field of metal crack detection, and discloses a metal microcrack ultrasonic detection method, which comprises the following modules: an ultrahigh frequency composite array probe with a center frequency dynamic adjustable range of 5-50 MHz; the dual-mode excitation and receiving module is used for independently generating a pulse reflection mode excitation signal and a diffraction mode chirp frequency modulation signal; the phase-controlled synthetic aperture dynamic focusing module is used for realizing + / -60-degree deflection and sub-wavelength level focusing of acoustic beams; the nonlinear harmonic enhancement module is used for exciting a crack nonlinear effect by superposing 1-2MHz fundamental waves; and a time-space-frequency three-domain data fusion module. According to the method, signal-to-noise ratio collapse caused by the diffraction effect in a traditional method is overcome, more importantly, the system has low-frequency penetrability and high-frequency resolution at the same time due to 80%-120% of broadband coverage of chirp frequency modulation signals, the diffraction signal gain is increased by 20 dB or above, a near-surface blind area is compressed to be within 0.2 mm, and the system can be applied to the field of radar imaging. And the core pain point of missing detection of the near-surface microcracks of the thin-wall component is solved.

The application discloses a large-scale plane one-way folding array antenna full-working-condition electric performance prediction method, which comprises the following steps: (1) determining a folding position according to a folding angle under different working conditions; (2) determining an array element position after folding according to the folding position and array antenna geometric parameters; and (3) determining a mode excitation coefficient according to each array element position information and single array element mode information, and then calculating electric performance under different working conditions. The application can quickly and accurately analyze folding array antenna radiation and scattering, and has important engineering significance for array antenna analysis and design.

The invention discloses an ultrasonic double-wave detection and monitoring method and an ultrasonic double-wave transducer, and the ultrasonic double-wave transducer comprises a piezoelectric element which is used for exciting a longitudinal wave signal and a transverse wave signal at the same time under the excitation of a single electric pulse; the backing layer is positioned on the back surface of the piezoelectric element and is used for absorbing longitudinal wave energy radiated to the back surface by the piezoelectric element; the matching layer is arranged between the piezoelectric element and the tested workpiece and is used for acoustic impedance matching; the electrical connection device is used for connecting an external excitation generator and receiving equipment; and the metal shell is used for packaging the piezoelectric element, the backing layer, the matching layer and the electrical connection device and is provided with a structure for applying pre-tightening force. According to the invention, dual-mode excitation is realized through a single piezoelectric plate structure, and the efficiency, precision and reliability of dual-wave ultrasonic detection are improved.

The application discloses an antenna pair with high isolation and low cross polarization level, which comprises a first radiation patch and a second radiation patch arranged as two half-circle ring structures, and the first radiation patch and the second radiation patch are connected through a first branch and a second branch; the first radiation patch and the second radiation patch work in a full-wave mode; the first branch and the second branch are arranged to overlap the resonant frequencies under differential and common mode excitation of two feed ports, and good matching is ensured, so that the isolation of the first radiation patch and the second radiation patch in the band is effectively improved; through the above arrangement, the mode Q value under differential and common mode excitation is close to the same, and the first radiation patch and the second radiation patch can further have high isolation in a wider frequency range. In addition, by introducing a first short pin group and a second short pin group, the polarization current in the x-axis direction can be effectively weakened, and the cross polarization level is reduced.

The invention discloses a dual-mode phase shifter based on artificial surface plasmon. The dual-mode phase shifter comprises a dual-mode transmission structure, a dual-mode excitation structure and a direct current control structure, the dual-mode transmission structure realizes simultaneous transmission of an even mode and an odd mode in a single physical channel; the dual-mode excitation structure ensures efficient excitation of an even mode and an odd mode, the even mode is directly excited by a microstrip port, and the odd mode is indirectly excited by a microstrip-slot line coupling mode; the DC control structure realizes real-time control of two modes of the dual-mode transmission structure. According to the invention, simultaneous transmission of an even mode and an odd mode under the same frequency and a single physical channel is realized, and independent control of phase electromagnetic characteristics of the two modes is realized according to the control method after introduction of semiconductor devices such as a variable capacitance diode, so that independent phase shift of two paths of signals under the same frequency is realized simultaneously, and the signal transmission efficiency is improved. And the phase shift ranges of the two paths of signals both cover 360 degrees.

A flowmeter is provided that includes a sensor assembly (10) and a meter electronics (20). The flowmeter further has one or more flow tubes (130, 130’) and a drive mechanism (180) coupled to the flow tubes (130, 130’) and oriented to induce a drive mode vibration therein. A pair of pickoff sensors (170L, 170R) is coupled to the flow tubes (130, 130’), and is configured to measure a vibrational response induced by the drive mechanism (180). At least one strain gage (200A, 200B) is coupled to the sensor assembly (10), and configured to detect a strain in the sensor assembly (10). The meter electronics (20) is connected to the drive mechanism (180) and the strain gage (200A, 200B) in series. The meter electronics (20) is configured to detect frequencies at which changes in strain are occurring.

The application discloses a compact W-band filter power divider with reverse output characteristics, comprising a band-pass filter network, an isolation-power distribution unit and an output coupling structure. After the input signal is filtered by the band-pass filter network, it enters the isolation-power distribution unit. The energy is coupled to the upper and lower symmetrical output channels through the input channel in the center of the cavity, forming an equal amplitude coupling mode, and then entering the output coupling structure. In the output coupling structure, the directional rotation of the curved waveguide in the two output channels introduces the directionality rotation, so that the TE 10 The main mode is mirror flipped in the process of propagating in the curved channel, and the inherent odd mode excitation characteristics in the superposition coupling channel are superimposed, so that a stable 180-degree phase difference is finally generated at the two output ports. The structure can realize the cooperative characteristics of equal amplitude power distribution, 180-degree output phase difference, deep out-of-band suppression and high isolation output, and meets the integration demand of a high-performance millimeter wave subsystem.

The invention relates to the technical field of intelligent fastener nondestructive testing, in particular to a high-temperature-resistant intelligent bolt and a stress detection method thereof. The bolt measuring end face is fixedly connected with an integrated chip through a couplant-free high-temperature welding process. The integrated chip is based on a piezoelectric material of a specific cutting type, the surface of the integrated chip is divided into an inner side ultrasonic electrode and an outer side resistance electrode through graphical etching, and dual-mode excitation and in-situ real-time temperature measurement of quasi-shear transverse waves and quasi-telescopic longitudinal waves are synchronously achieved on a single chip. By combining a matched initial wave multiple cross-correlation alignment algorithm, a frequency domain mapping acceleration algorithm and a dynamic temperature compensation algorithm, the problems of coupling medium failure, large temperature measurement error, hardware time drift and the like of a traditional ultrasonic bolt at high temperature are thoroughly solved, and high-precision and long-period dynamic monitoring of the bolt pre-tightening force under the extreme variable-temperature working condition of 280 DEG C is realized.

The invention discloses a method for calculating the mode purity of a high-quality factor TM010 over-mode cylindrical resonant cavity, and belongs to the field of electromagnetic field propagation. According to the method, structural details of a coupling hole, an end cover step and a fit clearance are covered in modeling; all possible competition modes are covered through functional region decomposition and electromagnetic field mode decomposition in combination with a mode excitation rule of an over-mode cavity; introducing power normalization processing, and establishing a unified amplitude comparison reference; based on the synergistic effect of scattering matrix cascading and electromagnetic field mode decomposition, the transmission, reflection and coupling processes of multiple modes in the cavity are completely described; according to the invention, the problems that only the mode purity of the port plane and the electromagnetic field distribution in the volume can be obtained and the mode purity of a specific mode in the volume of the resonant cavity cannot be accurately calculated in the prior art are solved; the method is applied to the core technologies of microwave communication, satellite load, particle acceleration, precision measurement and the like depending on high-quality factor resonant cavities to accurately calculate the TM010 mode purity in the volume of the resonant cavity.

The invention provides an ultrahigh-frequency film bulk acoustic wave device and a preparation method thereof, and the ultrahigh-frequency film bulk acoustic wave device achieves high-order mode excitation through a piezoelectric layer in a single polarization direction and a reverse electric field of an adjacent layer. According to the preparation of the ultrahigh-frequency film bulk acoustic wave device, only piezoelectric layers with identical polarization directions need to be prepared, a differential preparation process of piezoelectric films with multiple polarization directions does not need to be researched, developed and controlled, the complexity of the process steps is reduced, and the whole preparation process is based on mature semiconductor processes such as etching, deposition and sacrificial layer release. No special equipment or customization technology needs to be introduced, the threshold of technology research and development and production implementation is greatly reduced, through technology simplification, the manufacturing cost is reduced, and large-scale mass production can be achieved.

The invention provides a silicon photon gyroscope with a film-coated mode filtering double-Y waveguide integrated structure. The silicon photon gyroscope comprises a laser, a detector, a symmetrical double-Y waveguide, a first filter, a second filter, a third filter, a fourth filter, a first phase modulator, a second phase modulator and a ring, symmetrical optimization design is adopted for the symmetrical double-Y waveguides, namely mode excitation is reduced by conducting collaborative optimization on the front Y waveguide and the rear Y waveguide, the bifurcation angle of the front Y waveguide and the rear Y waveguide is controlled to be 8-12 degrees, the high-order mode excitation rate is controlled to be within 1%, and therefore space radiation mode errors and zero drift are remarkably reduced. A high-order mode excited in the beam splitting process is suppressed through the first and second filters, and a new mode of temperature gradient or stress introduction is prevented through the third and fourth filters; selective suppression of a high-order spatial mode is realized by adopting the filter with a film-coated structure, and meanwhile, low-loss transmission of a fundamental mode is kept, so that the zero-bias stability and the measurement precision of the silicon photon gyroscope are remarkably improved.

The invention discloses a conformal waveguide transmission line, which comprises an outer side bending metal layer, an inner side bending metal layer and a gap between the outer side bending metal layer and the inner side bending metal layer from the outer side to the inner side, the outer side bent metal layer is provided with a bent waveguide groove and two parallel bent long choke grooves, and the bent long choke grooves are arranged on the upper side and the lower side of the bent waveguide groove respectively and are separated by a bent metal wall. The inner side bent metal layer is provided with two rows of periodic choke grooves, the periodic choke grooves are periodically arranged along the surface of the inner side bent metal layer and arranged on the upper side and the lower side of the bent waveguide groove respectively, the centers of the periodic choke grooves are periodically arranged along the inner wall of the bent long choke groove, and the interval is lambda g / 6-lambda g / 2. The filter can maintain stable main mode propagation characteristics, inhibits high-order mode excitation and energy leakage, has low insertion loss, excellent impedance matching performance and strong environmental adaptability, and is suitable for high-frequency systems such as aerospace and intelligent automobile radar.

The present application belongs to the technical field of water turbine, and particularly relates to a method and structure for adjusting inherent frequency of a bucket of an impulse water turbine. The method comprises the following steps: according to the CFD calculation result, partitioning the back of the bucket, and determining the area affecting water power and the area not affecting water power; using a bucket root shaping method, establishing a three-dimensional model of the bucket; in the area not affecting water power, adding auxiliary lines and auxiliary surfaces, and constructing a frequency adjustment module through a stitching command; building a finite element model, applying boundary conditions, and solving; cyclically performing the following steps: extracting each section diameter mode under a torsional vibration mode and the corresponding inherent frequency, and comparing with the corresponding mode excitation frequency to determine whether resonance occurs; if resonance occurs, determining and deciding the adjustment direction, such as thickening the frequency adjustment module if the inherent frequency needs to be increased, or thinning the frequency adjustment module if the inherent frequency needs to be decreased; and determining the optimal thickness of the frequency adjustment module. The present application provides a simple and fast method and structure for adjusting inherent frequency of a bucket of an impulse water turbine.

The invention discloses a terahertz filter based on a bound state theory in an accidental continuous spectrum. According to the filter, the periodically arranged rectangular silicon column array is designed on the surface of the silicon dielectric layer, so that high-Q-value resonance mode excitation is realized. On the premise that the structural symmetry is not damaged, the frequency response of the filter can be accurately adjusted by adjusting periodic parameters, and the application requirements of different terahertz frequency bands are met. Compared with the prior art, the method does not need to depend on complex structure breaking design, the problem of unstable performance caused by manufacturing errors is avoided, the manufacturing process is simplified, and the production cost is reduced. Experimental verification shows that the narrow-band and high-Q-value frequency selective filtering can be realized in a predetermined frequency band, and the narrow-band and high-Q-value frequency selective filtering device has low insertion loss and high signal-to-noise ratio, has a relatively strong practical application prospect, and particularly has wide application potential in the fields of terahertz communication, sensing, spectrum detection and the like.

The application relates to the technical field of surface acoustic wave devices, and discloses a phononic crystal delay line based on in-plane rotation angle regulation of a band gap, which adopts a layered composite substrate composed of a lithium niobate piezoelectric substrate, a SiO2 dielectric layer and a SiC supporting substrate, input and output IDTs are arranged in parallel on the surface of the substrate, and a phononic crystal band gap structure is arranged on the sound wave propagation path between the two. The in-plane rotation angle alpha of the IDT and the phononic crystal is synchronously arranged, the sound mode excitation characteristics of the IDT and the band gap characteristics of the phononic crystal can be synchronously regulated by adjusting alpha. The application realizes the precise regulation of the band gap of SH- SAW priority, LL- SAW priority and mixed mode through three characteristic angles of 170 DEG, 40 DEG and 10 DEG, realizes the stray suppression of more than 40 dB in the frequency band of 2.4 GHz to 4.0 GHz, and reduces the insertion loss by more than 6 dB. The application is completely compatible with the traditional SAW manufacturing process, and can be widely applied to the fields of 5G / 6G communication, phased array radar, high-speed radio frequency signal processing and the like.

The invention belongs to the technical field of antennas, and discloses a multi-mode array antenna far field calculation method and related equipment, and the method comprises the steps: carrying out the characteristic mode analysis of a multi-mode antenna array element, and obtaining the electric field of each order mode and the characteristic value of each order mode; enabling the mode electric field of each order to be equivalent to a plurality of groups of infinitesimal dipole model parameters, and representing the actual current of the antenna array element based on the plurality of groups of infinitesimal dipole model parameters; using multiple groups of infinitesimal dipole model parameters and actual current to calculate an actual mode electric field of each order, and representing a mode coupling coefficient matrix of the mutual coupling effect of the whole array according to the actual mode electric field of each order; constructing and solving a balance equation of the whole array according to the characteristic value of each order of mode and the mode coupling coefficient matrix, and obtaining an array environment mode excitation coefficient of each order of mode current of the antenna array element under the consideration of the mutual coupling effect; and the radiation field of the whole multimode array antenna is calculated according to the array environment mode excitation coefficient, so that the calculation efficiency is remarkably improved.

The invention discloses a microstrip waveguide conversion structure, which comprises a non-standard rectangular waveguide, a stepped impedance conversion structure, a dielectric plate, a strip line and a vertical metal probe, the stepped impedance conversion structure is integrated in the non-standard rectangular waveguide; the dielectric plate is arranged at the top of the non-standard rectangular waveguide; the strip line is printed on the surface of the dielectric plate; the vertical metal probe is installed in the dielectric plate, the lower end of the vertical metal probe is inserted into the metal hollow cylinder to form electric connection, and the upper end of the vertical metal probe is connected with the strip line. According to the invention, the stepped impedance conversion structure is adopted to match the vertical metal probe, the probe is prevented from directly extending into the waveguide, and the design is changed into a waveguide surface fitting design, so that the risk of high-order mode excitation is reduced; one end of the vertical metal probe is connected with the microstrip line through a metal bonding pad, impedance continuity is optimized, and the influence caused by parasitic inductance is reduced; a stepped impedance conversion structure is introduced into the non-standard rectangular waveguide, and the working bandwidth is widened to 78%; and a low-loss dielectric plate is selected, so that the insertion loss is reduced.

The invention provides a semiconductor laser with a pattern electrode and a use method thereof, and relates to the technical field of semiconductor lasers. The semiconductor laser with the pattern electrode comprises a substrate; the deformed resonant cavity is arranged on the substrate, the shape of the deformed resonant cavity is a fillet, the deformed resonant cavity is used for generating photons, the photons are reflected for multiple times in the deformed resonant cavity and oscillate to generate laser, and the shape of the deformed resonant cavity is a fillet; the electric injection layer is arranged on a part of the upper surface of the deformed resonant cavity; and the non-injection layer is arranged on the other upper surface, not covered by the electric injection layer, of the deformed resonant cavity. According to the embodiment of the invention, the electrode design and the current injection regulation are optimized, so that the limitation of mode selective excitation of the laser is broken through, the performance and the application range of the deformation cavity laser are improved, and the problem that the precision and the stability of mode excitation of the laser are insufficient can be solved.

The invention discloses a compact W-waveband filtering power divider with an inverted output characteristic, which comprises a band-pass filtering network, an isolation-power distribution unit and an output coupling structure, and is characterized in that an input signal enters the isolation-power distribution unit after passing through the band-pass filtering network; energy is respectively coupled to the vertically symmetrical output channels through the input channel in the center of the cavity to form a constant-amplitude coupling mode, and then enters the output coupling structure. In the output coupling structure, due to the fact that directional rotation is introduced into bent waveguides in two output channels, a TE10 dominant mode is subjected to mirror image overturning in the space electric field direction in the curve propagation process, inherent odd mode excitation characteristics in the coupling channels are superposed, and finally a stable 180-degree phase difference is generated at two output ports. According to the structure, the cooperative characteristics of equal-amplitude power distribution, 180-degree output phase difference, depth out-of-band rejection and high-isolation output can be achieved, and the integration requirement of a high-performance millimeter wave subsystem is met.

The invention relates to a secondary and fourth harmonic generation method based on a thin film lithium tantalate micro-ring, which comprises two waveguide buses and an Euler curve micro-ring, the two waveguide buses are oppositely arranged on the upper and lower sides, the Euler curve micro-ring is arranged between the first waveguide bus and the second waveguide bus, the first waveguide bus of an S-shaped structure is arranged on one side of the Euler curve micro-ring, and the second waveguide bus of an S-shaped structure is arranged on the other side of the Euler curve micro-ring. The drop end of the second waveguide bus of the U-shaped structure is located on the other side of the Euler curve micro-ring. The micro-ring is used for replacing a straight waveguide structure, so that the interaction distance between light and substances is increased, and the harmonic conversion efficiency is remarkably improved. An Euler curve is used for replacing a circular ring waveguide, in-ring loss and high-order mode excitation are reduced, a single etching method is used, the preparation process is simple, and the process tolerance is larger.

The invention relates to electronic equipment. The electronic equipment comprises a floor, a radiator, a first parasitic branch knot, a second parasitic branch knot, a feed source and a tuning circuit, wherein the first parasitic branch knot comprises a first grounding point, and the first parasitic branch knot and the first end of the radiator are arranged at an interval and form a first gap; the second parasitic branch knot comprises a second grounding point, and the second parasitic branch knot and the second end of the radiator are arranged at intervals to form a second gap; the tuning circuit is respectively connected with the feed source and a first connection point and a second connection point on the radiator and is used for tuning an excitation signal provided by the feed source, and the tuned excitation signal excites the radiator and the floor to generate a first resonant mode supporting a first frequency band; the excitation radiator and the first parasitic branch generate a second resonance mode supporting a second frequency band, and the excitation radiator and the second parasitic branch generate a third resonance mode supporting a third frequency band, so that wide distribution of excitation current can be realized on the basis of being compatible with multi-frequency-band communication, and the SAR value is reduced.

This invention relates to the field of electromagnetic compatibility technology, and particularly to a method, device, electronic device, and storage medium for predicting far-field radiation from a communication power supply. The method includes: analyzing the common-mode noise propagation path of the communication power supply and establishing a dual-excitation-source radiation model containing both input port and output port common-mode excitation sources. This application achieves separate analysis of the radiation contributions from the input and output ports by establishing a dual-excitation-source radiation model; improves the accuracy of key parameters by obtaining the impedance parameters of each port separately and accurately converting the excitation source voltage using a sampling measurement circuit; further, it obtains the maximum radiation transfer function through full-angle simulation to ensure prediction coverage of the worst-case scenario; finally, it calculates the total radiation prediction value by integrating the above parameters, thus forming a complete and reliable prediction process that significantly improves the accuracy and practicality of far-field radiation prediction.

The invention belongs to the technical field of wireless power transmission, and discloses a pole-free omnidirectional quasi-static cavity resonance wireless power supply system based on dual-mode excitation. The system provides a structure scheme comprising a transmitting end, a cavity end and a receiving end aiming at the problems that a central pole structure affects the space integrity, the magnetic field distribution is not uniform, the receiving angle is sensitive and the like in the prior art. The cavity end adopts a regular prism magnetic conductive cavity and is combined with a cavity compensation capacitor, a dual-working mode of alternately exciting a first frequency and a second frequency in the cavity through a transmitting coil is adopted, and an omnidirectional quasi-static composite magnetic field which is uniform in space and insensitive in direction is formed in the cavity by utilizing frequency switching; the receiving coil can efficiently receive electric energy at any position in the cavity. According to the method, the space utilization rate and the practicability are effectively improved, the uniformity and the angle robustness of the magnetic field are enhanced, high-precision modeling and optimization are realized through a parameter extraction method, and the transmission efficiency in most areas is considerable.

The invention discloses a method for reducing the lowest available frequency of a reverberation chamber, and relates to the technical field of electromagnetic compatibility testing in a new generation of information technology, and the method comprises the following steps: S1, unit design and coding, S2, spherical surface type coding metasurface scatterer realization, S3, scatterer installation, S4, mode excitation and field uniformity improvement, and S5, LUF reduction realization. According to the invention, the small spherical surface type coding metasurface scatterer is additionally arranged in the RC, so that the effects of remarkably reducing the LUF, enhancing the uniformity of a low-frequency field, increasing the number of low-frequency modes and remarkably improving the low-frequency performance of the reverberation chamber with relatively low cost and modification are realized.

The invention discloses an antenna structure and electronic equipment, and relates to the technical field of antennae, and the antenna structure comprises a radiator which is provided with a gap, and the gap is an antenna radiation main body; one end of the excitation transformation network is connected with the feed source, the other end of the excitation transformation network is coupled with the radiator, and the excitation transformation network is used for working under the corresponding capacitance-inductance characteristic according to the frequency of the received radio frequency signal so as to realize multimode excitation of the feed source. According to the technical scheme provided by the invention, multi-mode excitation can be realized through one feed source, and the bandwidth of the antenna is increased.