20 results about "Normal waves" patented technology

An aircraft radome and radar assembly includes: a radome arranged on the nose of the aircraft; a radar inside the radome, the radar operating in the millimeter domain and including a transmission antenna for emitting a TM polarized wave and a reception antenna; the radome includes an integrated window in front of the radar, the window being of a material transparent to millimeter waves; the radar being arranged so the angle between the maximum gain direction of the transmission antenna and the normal to the window is within an angular range [θB−θ1; θB+θ2], with OB being the Brewster angle for an air / window interface, θ1 and θ2 determined to obtain reflectivity at said air / window interface less than a predefined threshold; and an isolation partition between the transmission antenna and the reception antenna, the isolation partition being substantially in contact with the window and with the radar.

The embodiment of the present application provides a grating structure, an optical waveguide device and a display device, and belongs to the technical field of display, the grating structure is arranged on the optical waveguide plate, the light in the optical waveguide plate is incident on the grating structure, the grating structure is used for changing the propagation direction of incident light or coupling out the incident light from the optical waveguide plate, the grating structure comprises: a plurality of sub-gratings arranged along a first direction and different in position;Wherein, the light-out angle range of at least two sub-gratings is different, the light-out angle range is the angle range of the light emitted by the sub-grating, and the angle range is the included angle range between the emitted light and the normal direction of the sub-grating. Through the grating structure, the optical waveguide device and the display device provided by the embodiment of the present application, the light efficiency waste caused by the grating structure can be reduced, and the light efficiency of the optical waveguide device is improved.

The application discloses a building steel structure weld ultrasonic nondestructive testing and flaw detection method and system, belongs to the technical field of weld detection, and the method comprises the following steps: acquiring weld surface laser point cloud data, calculating local normal direction and converting probe inclination; extracting noise amplitude sequence in a non-welding area, and constructing a noise statistics table; driving an ultrasonic array probe to generate a full matrix echo data set and a plane wave echo data set according to a scanning posture table; mapping into a full focus image and a plane wave superposition image, calculating amplitude difference to generate a fusion weight map; generating a fusion image based on the fusion weight map, performing regional segmentation by using the noise statistics table, and extracting a defect boundary coordinate table. The technical scheme of laser point cloud guided probe posture, dual-mode imaging fusion and adaptive noise segmentation can realize high-precision, automatic identification and objective quantitative evaluation of internal defects of a weld.

An acoustic wave device including an IDT electrode on a piezoelectric film, in which a Z-axis direction of a crystal is different from a direction of a normal to a major surface. An overlap region of the IDT electrode includes a central region and first and second edge regions. First and second dielectric films are stacked between the piezoelectric film and first and second electrode fingers in the first and second edge regions. When an angle between a first side surface of the first dielectric film and a major surface of the piezoelectric film is α1 and an angle between a second side surface of the second dielectric film and the major surface of the piezoelectric film is α2, α1≠α2 between at least one electrode finger of the first and second electrode fingers and the piezoelectric film.

FIELD: radar technology.SUBSTANCE: invention relates to passive methods of protecting radar stations (RLS) from homing high-precision weapons (HPW) with a passive homing head (PHH), which include anti-radar missiles (ARM). The radar station and an additional radiation source (ARS) synchronized with it emit coherent signals in the direction of the spatial position of the ARM. These devices represent a source of spatially diverse interference to the passive homing head of a missile. The normal to the phase front of the resulting electromagnetic wave differs from the normal to the phase front of the radar. As a result, the missile's passive homing head is oriented in the direction of the false target, which is different from the direction of the protected radar. The condition for the interference impact is the provision at the input of the receiving antenna of the PGSN of an inversion zone of the total wave front of the resulting signal of the radiation sources with certain amplitude-phase relationships, as well as the provision of a change in the angular velocity of rotation of the missile-target line of sight.EFFECT: increased radar's protection against anti-missile missile attacks by diverting its guidance trajectory to a false point from the protected radar.1 cl, 2 dwg

This invention discloses an intelligent early warning method, system, and medium for abnormal waves based on a three-branch bilinear gated fusion model, belonging to the field of marine engineering safety early warning technology. The method includes the following steps: constructing an original dataset containing normal wave samples and abnormal wave samples; constructing abnormal wave early warning samples based on a preset input time window and early warning period; extracting the first, second, and third feature vectors from a specific wavefront sequence using a three-branch feature extraction network; performing adaptive fusion through a bilinear gated fusion module to obtain the final fused features; inputting the final fused features into a classification and discrimination module, and outputting the probability of abnormal wave occurrence through multi-dimensional comprehensive analysis. This invention addresses the problems of scarce abnormal wave samples and highly imbalanced categories by introducing hybrid training, asymmetric loss, and false alarm suppression strategies to improve the stability and generalization ability of the developed model under real sea conditions.

Aircraft Radome and Radar Assembly The invention relates to an aircraft radome and radar assembly (EAR) comprising: a radome (Rd) disposed on the nose of the aircraft (NA); a radar (Ra), disposed inside the radome (Rd), the radar (Ra) being configured to operate in the millimeter range and comprising a transmitting antenna (Tx) configured to emit a TM polarized wave and a receiving antenna (Rx); the radome (Ra) comprising a window (F) integrated in said radome, the window (F) being in a material transparent to millimeter waves, the window (F) being opposite the radar (Ra); the radar (Ra) being disposed such that the angle (θi) between the maximum gain direction (DGM) of the transmitting antenna (Tx) and the normal (N) to the window (F) is within an angular range [θB - θ1;θB + θ2], with θB being the Brewster angle for an air / window interface, θ1 and θ2 determined to obtain a reflectivity at said air / window interface below a predefined threshold; and an isolation partition (IC) disposed between the transmitting antenna (Tx) and the receiving antenna (Rx), the isolation partition (IC) being substantially in contact with the window (F) and with the radar (Ra). Figure for the abstract: Fig. 1;

The present application belongs to the technical field of phased array radar monopulse and difference angle measurement, and particularly relates to a method for quickly generating angle discrimination curves of a monopulse radar at multiple pointing angles, which comprises the following steps: measuring the azimuth and elevation angle discrimination curves of the normal wave position of a phased array of a monopulse radar in a darkroom environment; scanning the beam pointing according to a designed trajectory, and synchronously rotating the turntable according to a corresponding designed trajectory to measure the difference and ratio data at the designed wave position; characterizing the deformation of the angle discrimination curves caused by the non-ideal factors of the phased array as translation and rotation, and calculating the translation coefficient C and the rotation factor K of the angle discrimination curves at different wave positions compared with the angle discrimination curves at the normal wave position based on the measured difference and ratio data; based on the obtained translation coefficient C and rotation factor K of the wave position, interpolating and predicting the C and K of all wave positions within the required wave position range; and based on the C and K of all wave positions, constructing a lookup table and writing it into the phased array radar to complete the quick generation of the angle discrimination curves of the monopulse radar at multiple pointing angles.

This invention relates to an aircraft radome and radar assembly (EAR), comprising: a radome (Rd) for the nose (NA) of an aircraft; a radar (Ra) within the radome (Rd), the radar (Ra) operating in the millimeter-wave band and including a transmitting antenna (Tx) and a receiving antenna (Rx) configured to transmit TM-polarized waves; the radome (Ra) includes a window (F) made of a millimeter-wave-transmitting material and located in front of the radar (Ra); the radar (Ra) is configured such that the angle (θi) between the maximum gain direction (MGD) of the transmitting antenna (Tx) and the normal (N) of the window (F) is within the angle range [θi]. B -θ1; θ B Within +θ2], θ B The Brewster angle of the air / window interface, θ1 and θ2 are determined to be the reflectivity obtained at the air / window interface below a predetermined threshold; and the isolation partition (CI) between the transmitting antenna (Tx) and the receiving antenna (Rx), the isolation partition (CI) being in contact with the window (F) and the radar (Ra).

The application discloses a kind of mud balance shield mud film identification permeameter test device and method, it is related to geotechnical engineering test field, it includes organic glass cylinder, air compressor, pressure gauge, pore water pressure gauge and ground penetrating radar detection system.The organic glass cylinder forms closed test cavity, air compressor is controlled air pressure to cavity interior by gas pressure regulating valve to drive mud penetration soil sample to generate mud film, and pressure gauge and pore water pressure gauge are used to monitor gas pressure in cavity and internal pore water pressure of medium.Radar antenna of ground penetrating radar detection system is installed in the way of emission surface no gap adhering to the top surface of organic glass cylinder, and the center normal direction is perpendicular to the layered interface of medium in cylinder, electromagnetic wave is vertically incident to obtain the best reflection echo signal.The application integrates ground penetrating radar and permeameter device structure, realizes the real-time nondestructive detection of mud film formation process.

This disclosure relates to the field of oil and gas exploration, and discloses a drilling azimuth electromagnetic resistivity antenna system structure and logging tool, including: a transmitting coil and a receiving coil; the normal directions of the transmitting coil and the receiving coil are both perpendicular to the drilling direction; the transmitting coil is used to transmit electromagnetic waves to the target formation; the receiving coil is used to receive electromagnetic waves reflected from the target formation. This disclosure overcomes the limitations of other azimuth electromagnetic resistivity measurements in horizontal wells and highly deviated wells, solves the problems of complex instrument design and low radial azimuth detection efficiency, and fully utilizes the accuracy, simplicity, and applicability of dual-transmitter, dual-receiver horizontal coil antenna systems. It achieves a more convenient instrument for radial measurement of azimuth electromagnetic resistivity and a higher standard for radial measurement accuracy, which plays an important role in saving costs and improving measurement efficiency. It can effectively solve the major problems of complex instrument design and operation, time-consuming maintenance, and low radial azimuth measurement efficiency.

Provided is an elastic wave device in which degradation of characteristics is less likely to occur. An elastic wave device (1) is provided with an IDT electrode (7) on a piezoelectric film (6) whose direction of the Z axis of the crystal is different from the direction of the normal line to the main surface, and a cross region (K) of the IDT electrode (7) has a central region (C) and first and second edge regions (D1, D2), in the first and second edge regions (D1, D2), first and second dielectric films (15, 16) are layered between the piezoelectric film (6) and first and second electrode fingers (13, 14), and when an angle (α1) formed by a first side surface (15a) of the first dielectric film (15) and a main surface (6a) of the piezoelectric film (6) and an angle (α2) formed by a second side surface (16a) of the second dielectric film (16) and the main surface (6a) of the piezoelectric film (6) are set, α1 ≠ α2 between at least one of the plurality of first and second electrode fingers (13, 14) and the piezoelectric film.

This application provides a surface acoustic wave (SAW) resonator, its manufacturing method, and a SAW filter. The SAW resonator includes: a substrate; the substrate includes a first sound velocity layer, a second sound velocity layer, and a piezoelectric layer; wherein the propagation speed of sound waves in the first sound velocity layer is greater than that in the second sound velocity layer; an interdigital transducer disposed on the surface of the piezoelectric layer away from the first sound velocity layer; wherein the interdigital transducer includes a plurality of spaced electrode fingers; a suppression structure disposed between any two adjacent electrode fingers; wherein the suppression structure is used to suppress the generation of interference waves propagating on the surface of the piezoelectric layer; with the normal direction of the substrate as the thickness direction, the thickness of the suppression structure along the normal direction of the substrate is less than the thickness of the electrode fingers. Through this application embodiment, the generation of interference waves propagating on the surface of the piezoelectric layer is suppressed, improving the out-of-band suppression performance of the resonator.

Embodiments described herein relate to a method of using an apparatus for forming waveguides. The method includes positioning a substrate at a first rotation angle, exposing the substrate to an ion beam, forming first partial trenches defined by adjacent angled device structures with the first device angle, rotating the substrate to a second rotation angle, exposing the substrate to the ion beam, etching the first partial trenches, and repeating the method from about 1 cycle to about 100 cycles to form a plurality of trenches defined by adjacent angled device structures. The first rotation angle is selected to form one or more angled device structures with a first device angle relative to a vector parallel to the substrate. The ion beam is configured to contact the substrate at a beam angle ϑ relative to a surface normal of the substrate.

An antenna module includes a dielectric substrate, a radiating element, a ground electrode, a feed line, a via connected to the radiating element, and an auxiliary electrode The ground electrode and faces the radiating element across the dielectric substrate. The feed line transmits a radio-frequency signal to a feed point of the radiating element, wherein the feed point is offset from the center of the radiating element in a first direction. The auxiliary electrode is connected to the via and is disposed between the radiating element and the ground electrode. The via is connected to the radiating element at a position offset from the center of the radiating element in a second direction opposite to the first direction. When viewed in plan from a normal direction of the dielectric substrate, the auxiliary electrode protrudes from the radiating element toward the second direction.

The application discloses a method for detecting the perpendicularity of a to-be-detected plane, which comprises the following steps: adjusting the wave front of an incident light beam through a two-dimensional ultra-thin Fresnel thin film lens to form an axially propagating stable quasi-Bessel light beam; and detecting the normal direction or collimation state of the plane based on the spot pattern evolution characteristics of the quasi-Bessel light beam when the Fresnel thin film lens is tilted, so as to realize the detection stability and engineering applicability of the perpendicularity of the to-be-detected plane without complex refractive optical structures and multi-stage calibration. Furthermore, the structure parameters and diffraction orders of the Fresnel thin film lens can be designed and customized in advance according to the detection requirements of the to-be-detected plane, so as to be applicable to application scenarios with different plane perpendicularity detection precisions.

Optical systems for performing gaze tracking and imaging an external scene are disclosed. An example optical system may include light sources for emitting visible and non-visible light. The optical system may include a waveguide that is operatively coupled to the light sources. A volume holographic light coupling element may be disposed between the surfaces of the waveguide. The volume holographic light coupling element may include a grating medium and a first volume holographic grating structure within the grating medium. In some examples, the first volume holographic grating structure may be configured to reflect non-visible light of a first wavelength about a first reflective axis offset from a surface normal of the grating medium at a first incidence angle. The optical system may also include an optical filter. Another example optical system may include an imaging device that is configured to receive the light external to the optical system.