259 results about "Phase velocity" patented technology

An improved E-field generator including a slow-wave transmission line structure is provided herein. In some cases, the improved E-field generator may include an inductively-loaded slow-wave transmission line structure driven by a power source at one end of the structure and terminated by a load at the other end of the structure. In other cases, the improved E-field generator may include a capacitively-loaded slow-wave transmission line structure. In either case, the improved E-field generator provides a frequency-independent, significantly increased electric field at a distance spaced from the generator without altering the dimensions of the generator and/or the input power supplied to the generator. The increase in generated field intensity is achieved by decreasing the phase velocity of the electromagnetic wave propagating along the parallel elements of the generator.

A fixed frequency continuously beam-steerable leaky-wave antenna in microstrip is disclosed. The antenna's radiating strips are loaded with identical shunt-mounted variable-reactance elements, resulting in low reverse-bias-voltage requirements. By varying the reverse-bias voltage across the variable-reactance elements, the main beam of the antenna may be scanned continuously at fixed frequency. The antenna may consist of an array of radiating strips, wherein each strip includes a variable-reactance element. Changing the element's reactance value has a similar effect as changing the length of the radiating strips. This is accompanied by a change in the phase velocity of the electromagnetic wave traveling along the antenna, and results in continuous fixed-frequency main-beam steering. Alternatively, the antenna may consist of two long radiating strips separated by a small gap, wherein identical variable-reactance elements are mounted in shunt across the gap at regular intervals. A continuous change in the reactance value has a similar effect as changing continuously the width of the radiating strips. This results in a continuous change in the phase velocity of the electromagnetic wave traveling along the antenna, thereby achieving continuous fixed-frequency main-beam steering.

This invention discloses a two-phase flow digital particle image speed test method and its device, which uses suitable particles to trace flow of fluids and uses high speed CCD camera to register motion images for tracing particles, liquid drops or gas bubbles, applies an image process method to separate the images of scattered phase particles drops or bubbles from original images and extracts velocities of them from their images and applies an improved cross correlation technology based on quick Fourier transformation to extract the velocity field of the tracing particles to realize the synchronous measurement to the two phase flows with different phase velocity fields. The device includes a HeNe laser, a triple prism and a cylinder lens, a high speed CCD camera, an image collecting card and a control and image process computer.

A method of determining at least one parameter of a waveguide (3) from wavefield data acquired from wave propagation in the waveguide including obtaining first and second dispersion curves (9a, 9b, 9c) in the frequency domain from the wavefield data. A frequency interval between the first dispersion curve and the second dispersion curve is found, and this is used in the determination of at least one parameter of the waveguide. The frequency separation Δƒ(V) between the first and second dispersion curves may be found at a particular value of the phase velocity V, and the thickness h of the waveguide can be found using:

Here, c₁ is the velocity of wave propagation in the waveguide. This may be found from the asymptotic velocity values of the dispersion curves.

A grating coupled surface plasmon resonance optical modulator is disclosed. A electro-optic polymer dielectric is deposited on the metallic surface of a diffraction grating to provide a metal/dielectric interface. A surface plasmon will propagate at the metal/dielectric interface in a resonant condition, e.g., when the metal surface is illuminated by transverse magnetic (TM) polarized light of the appropriate wavelength, angle of incidence and phase velocity. In the present invention, phase velocity is controlled by the diffraction grating. A transparent electrode deposited on the electro-optic layer allows an electrical potential to be applied across the electro-optic polymer. The applied electrical potential (voltage) changes the index of refraction of the electro-optic polymer, thereby disrupting the resonant condition to produce an optically detectable change in reflectance of incident light from the metal layer. The disclosed grating coupled surface plasmon resonance optical modulator may be configured as an electronically or optically addressable array.

Methods and apparatus for implementing standing wave oscillators (SWOS) using coplanar striplines (CPS). One example is given by a quarter-wavelength (λ/4) coplanar stripline standing wave oscillator (SWO), while another implementation utilizes a closed-loop coplanar stripline configuration. In various aspects, SWOs are configured to optimize sinusoidal performance at high frequencies with low power dissipation by incorporating various features that dramatically increase the quality factor Q of the oscillator. In particular, in one aspect, an amplitude-dependent tailored distributed amplification scheme is employed as a mode control technique using multiple amplifiers having different gains along the length of the coplanar stripline. In another aspect, a coplanar stripline configured such that its resistance per unit length R and conductance per unit length G are discreet or continuous functions of position along the coplanar stripline is employed to reduce SWO losses. In another aspect, an enhancement of the quality factor Q is achieved while at the same time reducing the phase velocity of waves propagating in the SWO, thereby also facilitating the fabrication of relatively smaller devices. In yet another aspect, SWOs are configured with frequency adjustability that is again optimized to reduce power dissipation while facilitating significant adjustments of oscillator frequency.

Aspects of the present invention are directed to using surface acoustic wave (SAW) sensors mounted on a disc coupling component in a powertrain to measure the torque generated by an automobile engine. The sensor may be positioned and oriented on the disc coupling component so that the phase velocities of SAWs propagating through active elements of the SAW sensors are aligned with principal strain components due to torque in the disc coupling component. The torque may be calculated by determining the difference between resonant frequencies of the active elements to suppress common-mode interference factors. In addition, SAW resonant frequencies may be communicated in a non-contacting manner by utilizing rotary and stationary couplers employing radio frequency (RF) signals. Moreover, SAW sensors may be activated and interrogated by employing targeted RF pulses having different carrier frequencies at or near respective resonant frequencies of each resonator in a SAW sensor.

A grating coupled surface plasmon resonance optical modulator is disclose. A electro-optic polymer dielectric is deposited on the metallic surface of a diffraction grating to provide a metal/dielectric interface. A surface plasmon will propagate at the metal/dielectric interface in a resonant condition, e.g., when the metal surface is illuminated by transverse magnetic (TM) polarized light of the appropriate wavelength, angle of incidence and phase velocity. In the present invention, phase velocity is controlled by the diffraction grating. A transparent electrode deposited on the electro-optic layer allows an electrical potential to be applied across the electro-optic polymer. The applied electrical potential (voltage) changes the index of refraction of the electro-optic polymer, thereby disrupting the resonant condition to produce an optically detectable change in reflectance of incident light from the metal layer. The disclosed grating coupled surface plasmon resonance optical modulator may be configured as an electronically or optically addressable array.

A surface acoustic wave element is provided including an IDT and reflectors provided on both sides of the IDT that are on a surface of a quartz plate. The quartz plate is made from an in-plane rotated ST cut quartz plate whose cutting angle is expressed as (0°, 113°-135°, ±(40°-49°)) by defining and using Euler angle. The IDT and reflectors are arranged at a slant of PFA±3° with respect to a direction of a phase velocity of a surface acoustic wave in the quartz plate. If the cutting angle of the quartz plate is expressed by the Euler angle (φ°, θ°, Ψ°), the power flow angle PFA is expressed that the PFA=0.374 (θ°−90°)−10.0°.

In a surface acoustic wave (SAW) device, such as a SAW resonator or a SAW filter, loss is minimized and steep characteristics are improved. IDT electrodes and a reflector are provided to a piezoelectric substrate cut out at a cut-angle which allows the substrate to excite a leaky surface acoustic wave (LSAW). The IDT electrodes have a given film thickness and a given pitch “p” of finger-electrodes. A phase velocity of the SAW is reduced to slower than a phase velocity “vb”of a slow shear wave propagating on the piezoelectric substrate, and a resonance frequency “f” satisfies a relation of 2×p≦vb/f. This structure allows the use of a Rayleigh surface acoustic wave (RSAW) which does not produce propagation loss, and improving insertion-loss and steep characteristics from those of a conventional SAW device using the LSAW.

The invention relates to an inversion method of stratum shear wave velocity radial sections. The inversion method includes: performing acoustic logging while drilling and while drilling stratum density and well diameter logging in a depth interval, and obtaining while drilling monopole and quadrupole array acoustic full wave train data, a while drilling stratum density logging curve and a while drilling well diameter logging curve; obtaining stratum longitudinal wave velocity and shear wave velocity at the position of processing depth through calculation, and extracting phase velocity frequency dispersion data of while drilling quadrupole wave; calculating a theoretical while drilling quadrupole wave frequency dispersion curve at the position of the processing depth; constructing an inversion objective function in a combined mode; outputting equivalent alteration velocity and thickness; calculating continuously variable stratum shear wave velocity radial sections; and repeating the steps until processing of the whole depth interval is finished, and obtaining the stratum shear wave velocity radial sections changing continuously along with logging depth. The inversion method of stratum shear wave velocity radial sections has the advantages of obtaining changes of mechanics/acoustic parameters nearby a well in real time, solving the problem of ununiqueness of inversion, and improving reliability of inversion results.

The invention discloses a quasi-surface plasmon-based leaky-wave antenna, and belongs to the technical field of microwaves. The leaky-wave antenna comprises a feed network and a radiating element, wherein the feed network comprises a gradient matching structure; the gradient matching structure is used for achieving conversion of an electromagnetic wave between a TEM mode or a quasi-TEM mode and a quasi-surface plasmon mode; and the radiating element is a quasi-surface plasmon waveguide capable of enabling the phase velocity of the transmitted quasi-surface plasmon to discontinuously change. Compared with the prior art, the radiating element of the leaky-wave antenna is achieved on the basis of the quasi-surface plasmon waveguide for a phase velocity modulation; the quasi-surface plasmon-based leaky-wave antenna is simple in structure, relatively small in interference to an external circuit and relatively easy to process, and does not need metal ground; and omnidirectional radiation and frequency scanning functions are relatively easy to achieve.

The present invention proposes a coupling device, comprising a substrate (1), a conductive layer (2) covering a first surface of said substrate (1), at least two electromagnetically coupled lines (3a, 3b) being provided opposite to said first surface and at least one thereof being covered by at least one cover layer (4, 5) wherein at least one capacitor (C1, C2, C3, C4) is connected between a first end of at least one of said at least two lines (3a, 3b) and said conductive layer (2). The at least one capacitor is a buried capacitor grounded in order to equalize unequal phase velocities otherwise degrading the performance of e.g. broadside coupled structures in an inhomogeneous substrate structure such as for example microstrips in a multilayer LTCC. Therefore the present invention enables coupling devices having a high performance and offering in that way the best of all possible design scenarios in terms of wideband performance, size and cost.

The invention provides a metal plate micro-defect detection method based on nonlinear Lamb waves. The metal plate micro-defect detection method comprises the following steps of: S1, acquiring a phasevelocity frequency dispersion curve and a group velocity frequency dispersion curve of a metal plate; S2, acquiring an excitation frequency, Lamb waves of a specific mode and an incident angle of theLamb waves of the specific mode as model parameters according to the phase velocity frequency dispersion curve and the group velocity frequency dispersion curve; S3, deriving a relative nonlinear coefficient beta' according to the Lamb waves of the specific mode in the S2, wherein the relative nonlinear coefficient beta' is used for representing the depth of a defect; S4, establishing a nonlinearultrasonic test system according to the model parameters; and S5, testing the metal plate according to the nonlinear ultrasonic test system established in the step S4, judging whether the relative nonlinear coefficient beta' is reliable or not, and if so, representing the defects of the tested metal plate by utilizing the relative nonlinear coefficient beta'. According to the metal plate micro-defect detection method, the relative nonlinear coefficient beta' represents the defects of the tested metal plate, the defects of the metal plate can be effectively represented, and the detection precision is improved.

The invention provides a method for modeling a reflection coefficient of a spherical PP wave in a viscoelastic medium and belongs to the field of geophysical prospecting for petroleum. The method comprises steps as follows: (1) a longitudinal wave phase velocity vp and a quality factor Q<-1> are calculated on the basis of a White model: the longitudinal wave phase velocity vp and the quality factor Q<-1> are calculated on the basis of the White model and reservoir parameters; (2) a reflection coefficient of a planar PP wave in a dispersive porous medium is calculated: the longitudinal wave phase velocity vp and the quality factor Q<-1> which are obtained in Step (1) are introduced in a Zoeppritz equation of the dispersive medium, and the reflection coefficient R<*>PP of the planar PP wave in the dispersive porous medium is calculated; (3) the reflection coefficient of the spherical wave is calculated: after the reflection coefficient R<*>PP of the planar PP wave is calculated in Step (2), the reflection coefficient of the spherical PP wave in the dispersive porous medium is modeled with a planar wave decomposition algorithm of the spherical wave, and the reflection coefficient R<spherical>PP of the spherical PP wave in the dispersive porous medium is calculated.

Provided are a distributed analog phase shifter and a method of manufacturing the same, which reduce a change in a characteristic impedance while changing a phase velocity with respect to an applied voltage. In the distributed analog phase shifter, a coplanar waveguide (CPW) is formed in a line form on a substrate. A plurality of ferroelectric capacitors is periodically loaded to the CPW. The ferroelectric capacitors include a ferroelectric film in a pattern form and defines the ferroelectric film affected by the applied voltage within an area of the ferroelectric capacitors. Accordingly, the change in the phase velocity with respect to the applied voltage is maintained without the change of the CPW characteristic and a return loss characteristic and a total insertion loss are improved since a total dielectric loss of the ferroelectric film is decreased.

A method for detecting isotropic material surface Young modulus by using surface acoustic wave technology. The method is as below: exciting broadband surface acoustic wave in an isotropic specimen surface to obtain a dispersion curve on a surface acoustic wave propagation direction; fitting the actual phase velocity data to obtain a closest truth-value phase velocity and a phase velocity fluctuation section; establishing a Cartesian coordinate geometry model to obtain a surface wave basic propagation equation containing unknown medium Young modulus, Poisson ratio, direction cosine of the propagation direction, amplitude attenuation coefficient given according to experience value, wave number and wave velocity; calculating assumption corresponding relation between wave velocity and wave number in the Cartesian coordinate geometry model and simultaneous theoretical relationship, to obtain mutual relationship of velocity, frequency and Young modulus under ideal conditions; and conducting reverse calculation to obtain the Young modulus in medium according to the mutual relationship of velocity, frequency and Young modulus under ideal conditions and the dispersion curve under actual conditions. The invention realizes effective measurement of isotropic material surface young modulus.

The present invention relates to a dual velocity method and apparatus for measuring flow rate of a fluid, independent of flow regime, the fluid having a plurality of components, at least one of which is capable of existing in an oil continuous phase emulsion in a conduit. The present invention only measures component fluid flow rates for components of the fluid which may include at least an oil continuous phase emulsion, but not a component including a water continuous phase emulsion. Velocity slip is directly determined by cross correlations of fluid electrical property signals which are used to measure the two most predominant velocities in a multiphase velocity distribution. Furthermore, phase velocity measurements are further improved by cross correlating signals from a pair of downstream sensors which are shifted a predetermined radial angle offset from corresponding pair of upstream diametrically positioned sensors.

The invention discloses a frequency-domain higher-order sound wave equation forward modeling method based on directional derivative, belongs to the technical field of seismic exploration, and aims at providing a frequency domain two-dimensional scalar sound wave equation forward modeling simulation method with the higher simulation precision. The method comprises the steps: building a fourth-order 17-point finite difference equation comprising a plurality of weighting coefficients according to a frequency domain scalar sound wave equation through the directional derivative; carrying out the normalized phase velocity frequency dispersion analysis, and solving an optimal weighting coefficient through an optimization algorithm; constructing a finite difference equation with the absorbing boundary condition; carrying out the seismic wave field data simulation through the fourth-order 17-point finite difference equation, and obtaining a seismic wave forward modeling record. The method can inhibit the frequency dispersion to the greatest extent, improves the simulation precision of the seismic wave field data, and also can adapt to a condition that the longitudinal and lateral grid sizes are not equal. The method is mainly used in the technical field of seismic exploration, and provides basic data and technological support for the simulation and analysis of a seismic wave field, the seismic inversion imaging, and geologic modeling.