39 results about "Electromagnetic reflection" patented technology

The invention discloses a mechanical non-resonant one-bit phase electromagnetic reflection metasurface unit, and belongs to the field of artificial electromagnetic materials. The unit comprises a non-resonant electromagnetic structure and a mechanical driving device. The non-resonant electromagnetic structure comprises a dielectric layer, an air layer and an adjustable metal backboard from top to bottom; the mechanical driving device adopts a bidirectional self-holding electromagnet, a screw rod of the bidirectional self-holding electromagnet is connected with the metal back plate, the back plate is driven to be switched between two preset positions through forward / reverse pulse current, the thickness of an air layer is accurately adjusted, and therefore one-bit dynamic switching of a reflection phase between 0 degree and 180 degrees is achieved through propagation phase accumulation. In the 5G millimeter wave frequency band of 20 GHz to 29.5 GHz, the reflection coefficients of the two states are both larger than 0.99, the phase difference is stabilized within 180 degrees + / -20 degrees, and good robustness is achieved for mechanical displacement deviation. The unit has the advantages of zero static energy consumption, low insertion loss, wide bandwidth, simple structure and simple control, and is suitable for a low-power-consumption intelligent reflecting surface and a dynamic beam forming system.

The application belongs to the technical field of test and measurement, and particularly relates to a tight-field reflecting surface realized by building cement. The tight-field reflecting surface is used for low-frequency tight-field measurement and mainly comprises a cement support, a cement parabolic reflecting surface arranged on the cement support, a surface geometry of the cement parabolic reflecting surface being a parabolic surface with periodic side teeth, and a metal plating layer formed on the surface of the cement parabolic reflecting surface and used for providing a metal boundary condition for electromagnetic reflection. The application can greatly reduce manufacturing cost and effectively form a high-quality quiet zone in a low-frequency band.

The invention discloses an anti-electromagnetic interference shielding type optical fiber connector structure and a manufacturing method, and belongs to the technical field of optical fiber connectors. The optical fiber connector structure comprises a shielding conductive shell, and the two ends of the shielding conductive shell are connected with a first connecting piece and a locking assembly respectively; the end, away from the shielding conductive shell, of the first connecting piece is fixedly provided with an annular conductive contact piece, a bearing inner core base is coaxially arranged in the shielding conductive shell, the bearing inner core base and the shielding conductive shell are connected through a compensation assembly, and the bearing inner core base is composed of a structure with two large cylinders at the two ends and a small cylinder in the middle. And an optical fiber insertion core assembly is coaxially arranged in the bearing inner core seat. By adopting the structure and the manufacturing method, the electromagnetic absorption layer is arranged between the outer wall of the bearing inner core seat and the shielding conductive shell, and high-frequency electromagnetic waves entering the shell are absorbed and attenuated by using a ferrite or carbon nanotube composite wave-absorbing material, so that electromagnetic reflection and secondary interference are reduced, and the overall anti-interference performance is improved.

The application discloses a microwave intrusion detector testing system, method, equipment, medium and product, and relates to the technical field of nuclear security physical protection effectiveness testing. The system comprises a robot moving device, which is used for carrying a testing tool and a central control module, and performing a preset test motion track in a test site. The testing tool comprises a microwave reflector simulation unit, a posture monitoring module and a signal source unit, which are respectively used for simulating electromagnetic reflection characteristics, collecting real-time posture data of the microwave reflector simulation unit and transmitting microwave signals. The central control module is used for controlling the robot moving device and the testing tool, and sending the acquired test data to a data analysis module. The data analysis module is in communication connection with the central control module, and is used for analyzing the test data acquired by the central control module and generating a test report. Therefore, the application improves the accuracy of the test result of the microwave intrusion detector.

The film is of a layered structure, the middle of the film is an organic base material, the base material comprises a first surface and a second surface, and a transition layer, an electromagnetic absorption layer, an isolation layer, an electromagnetic reflection layer and a thermal radiation reflection layer are sequentially distributed on the first surface and the second surface. Meanwhile, penetrating through holes are distributed in the surface of the film, and conductive layers are attached to the inner walls of the through holes to communicate all the layers. The thin film utilizes the closed reflection effect of the electromagnetic reflection layer and the loss effect of the electromagnetic absorption layer, and the electromagnetic shielding effectiveness of the thin film in the wave band of 10 MHz to 10 GHz is larger than 80 dB; the hemispherical emissivity of the heat radiation reflecting layer on the outermost layer is 0.03-0.05, and the solar absorptivity is 0.09 + / -0.02. The preparation method of the thin film comprises the steps of substrate plasma modification, magnetron sputtering deposition of the multi-layer functional film, punching, vacuum evaporation plating of the heat radiation reflecting layer, annealing treatment and the like, and the process controllability is high. The thin film integrates the functions of electromagnetic shielding, thermal control, static prevention and heat dissipation, and has important application value in the field of aerospace equipment.

The invention discloses a high-precision electromagnetic detection device, which belongs to the technical field of radiation emission testing and comprises a movable base, a mast is arranged on the upper surface of the movable base, a linear module is vertically arranged in the mast, a fixing plate is mounted on the surface of a sliding table of the linear module, and an antenna assembly is mounted on the upper surface of the fixing plate. By arranging the antenna assembly, the physical length of the antenna can be dynamically adjusted, half-wavelength resonance conditions of different test frequency bands can be matched in real time, dynamic impedance matching is achieved in continuous scanning, polarization switching can be completed through electric control in the static state of the physical structure by arranging the horizontal polarization unit and the vertical polarization unit, and the test efficiency is improved. Cable abrasion, phase instability and vibration interference caused by mechanical rotation are avoided, the measurement consistency is guaranteed, rapid complete polarization scanning is supported, the test efficiency and precision are effectively improved, electromagnetic reflection interference can be restrained through annular scattering ribs arranged on the surface of the mast, and the measurement accuracy is further enhanced.

The invention relates to the technical field of photoelectric materials, in particular to an electromagnetic and infrared compatible flexible film material which is formed by sequentially arranging five layers of materials, and the five layers of materials sequentially comprise a metal film layer, an electromagnetic absorption layer, an electromagnetic transition layer, an infrared base film layer and an infrared low-emission layer from bottom to top. The electromagnetic / infrared compatible flexible film material prepared by the method provided by the invention is thin in thickness, light in weight and good in weather resistance, and is very suitable for reducing electromagnetic reflection and keeping low infrared emission performance at the same time.

According to the composite bamboo pipe, a modified round bamboo pipe subjected to interface modification and pore in-situ foaming filling treatment serves as a bearing framework, the outer layer is annularly restrained through a glass fiber layer (an electromagnetic impedance matching layer), and the inner layer is rigidly supported through a carbon fiber layer (an electromagnetic reflection back plate layer); the structure has a mechanical bearing function and an electromagnetic absorption function, and from the perspective of mechanics, an annular restraint layer, a bearing framework and an internal rigid supporting layer are formed from outside to inside, so that the rigidity of the whole composite bamboo pipe is greatly improved, and the composite bamboo pipe is suitable for being applied to different fields; from the perspective of electromagnetism, the impedance matching layer, the loss layer and the conductive reflection back plate are formed from outside to inside, and therefore the integrated round bamboo composite pipe integrating the mechanical bearing function and the electromagnetic stealth function is formed.

The present subject matter disclosed herein relates to a radio frequency identification (RFID) device and manufacturing system are disclosed. The RFID device includes an antenna configured to operate at a predetermined frequency, a ground plane, and a dielectric spacer positioned between the antenna and the ground plane. The dielectric spacer has a thickness and dielectric constant configured to maintain the predetermined frequency and sensitivity of the antenna when the RFID device is in proximity to items containing high dielectric constant materials. An electrical connection between the antenna and the ground plane is formed, with the ground plane shielding the antenna from electromagnetically reflective surfaces. The manufacturing system includes supply mechanisms for the antenna, dielectric spacer, and ground plane, and a connection mechanism to form the electrical connection. A method of manufacturing the RFID device is also provided, involving positioning the components and forming the electrical connection.

The invention discloses a heat dissipation electromagnetic shielding film for spaceflight and a preparation method thereof, the prepared film is of a multi-layer structure, and a transition layer, an electromagnetic absorption layer, an isolation layer, an electromagnetic reflection layer and a thermal radiation reflection layer are sequentially arranged on a first surface of a base material; an electromagnetic reflecting layer, a heat radiation reflecting layer, a heat radiation layer and an anti-static layer are sequentially arranged on the second surface of the conductive base material; through holes are distributed in the surface of the electromagnetic shielding film; metal coatings are attached to the inner walls of the through holes, and all layers of the thin film are communicated through the metal coatings. The anti-static layer is prepared by sequentially sputtering the electromagnetic reflecting layer on the second surface of the base material, depositing the thermal radiation reflecting layer through vacuum evaporation, then coating the thermal radiation layer and curing, and coating conductive liquid or in a magnetron sputtering mode. The second surface of the electromagnetic shielding film has low solar absorptivity and high hemispherical emissivity, the solar absorptivity is less than or equal to 0.40, the hemispherical emissivity is not less than 0.60, and the electromagnetic shielding film has a good heat dissipation function and adapts to harsh application scenes in the aerospace field.

Radar sensors are disclosed. A radar sensor includes an antenna layer having antenna elements and a compound radome including an absorber layer on top of the antenna layer and a cover layer on top of the absorber layer. The absorber layer has a higher electromagnetic absorption than the cover layer. The compound radome includes a primary region in which the absorber layer has a reference absorber thickness and the cover layer has a reference cover thickness, and a secondary region in which the absorber layer has a secondary absorber thickness and the cover layer has a secondary cover thickness. The secondary cover thickness is different than the reference cover thickness. For a first angle of incidence, electromagnetic reflectivity is at a minimum within the primary region, and for a second angle of incidence different than the first angle of incidence, electromagnetic reflectivity is at a minimum within the secondary region.

The invention relates to the technical field of water resource management, in particular to a water quality regulation and ecological control system based on intelligent sensing, which comprises a pressure water depth detection module, an acoustic signal analysis module, a layered temperature calculation module, a water quality state judgment module and an ecological control instruction generation module. According to the method, continuous water depth coordinates are constructed through the relationship between pressure change and density, water body density space distribution is formed by combining electromagnetic reflection signal frequency domain characteristics, the vertical layering state of a water body is clearly expressed, temperature data are mapped and corrected under the density constraint condition, and a layering water temperature target with space directivity is formed. The water quality ecological state judgment is completed by combining the temperature gradient and the dissolved oxygen deviation, and a differential adjustment strategy is generated according to the abnormal region position and the risk weight, so that layered and partitioned accurate intervention is realized, the matching degree of the adjustment measure and the actual water body state is enhanced, and the continuity and controllability of water environment management are improved.

A low scattering turntable for improving quiet zone test performance and a quiet zone test method is provided, and relates to the technical field of quiet zone test. The low scattering turntable includes an L-shaped baffle, a rhombic inclined wedge supporting column, a bottom plate, a turntable base, a fixed block, a longitudinal rotating shaft and a transverse rotating shaft. In the disclosure, the rhombic inclined wedge supporting column is adopted, the sharp wedge diffraction and traveling wave scattering effects are reduced. Multi-layer side wave-absorbing materials layout are used in the rhombic inclined wedge supporting column, which can effectively reduce electromagnetic reflection and scattering in a wide frequency range. By adding sawtooth wave-absorbing material to the edge of L-shaped baffle, the reflection intensity of electromagnetic wave is reduced and the overall wave-absorbing efficiency is improved. The oval bottom plate is adopted to reduce the measurement error.

Disclosed and described herein are systems, methods and device for drone-based multi-physics measurement and acquisition wherein a drone flies above samples to rapidly acquire a large volume of data (standard photos, multispectral images, acoustic reflection data, and electromagnetic reflection data, among others). By integrating data acquired by the conventional camera, multispectral camera, acoustic / electromagnetic systems, and other sensor systems, accurate information on lithology, composition, elastic properties, and the like of the samples can be obtained without the need for time-consuming manual analysis.

The invention discloses an aramid nanofiber-based gradient structure composite electromagnetic shielding material and a preparation method thereof, and belongs to the technical field of electromagnetic shielding materials. Comprising an impedance matching layer, an electromagnetic absorption layer and an electromagnetic reflection layer which are stacked from top to bottom; wherein the material of the impedance matching layer comprises aramid nanofiber and Fe3O4; the electromagnetic absorption layer is made of aramid nanofibers and carbon nanotubes; and the electromagnetic reflecting layer is made of aramid nanofibers, polypyrrole and carbon nanotubes. According to the invention, an aramid polymer solution is used as an adhesive and gradient structure design is carried out, a magnetic material is introduced to promote electromagnetic wave incidence and reduce surface reflection, efficient attenuation of electromagnetic waves is realized through a continuous conductive network constructed by carbon nanotubes, and a strong reflection layer is formed by polypyrrole coated aramid nanofibers with a core-shell structure and the carbon nanotubes, so that the electromagnetic wave attenuation is improved. Therefore, the problems of poor mechanical property and insufficient electromagnetic shielding property of the composite electromagnetic shielding material are solved.

The invention discloses a self-sensing electromagnetic reflection scattering response regulation and control device and method, and the device comprises a reconfigurable electromagnetic metasurface which comprises a plurality of metasurface units which are arranged at intervals, and each metasurface unit achieves the reflection phase adjustment of the metasurface unit through the flowing position of liquid metal in a micro-channel; the reconfigurable planar antenna comprises a plurality of antenna units, and the antenna units realize the frequency and directional diagram reconstruction of the antenna through the flowing position of the liquid metal in the micro-channel; and the driving control unit is used for generating a coding sequence of the reconfigurable electromagnetic metasurface according to the incident wave electromagnetic parameters sensed by the reconfigurable planar antenna and driving liquid metal in the reconfigurable electromagnetic metasurface to flow according to a position state corresponding to the coding sequence. According to the invention, the frequency and direction of incident electromagnetic waves are sensed by the reconfigurable planar antenna, real-time coding adjustment of the metasurface array is realized, and then adaptive electromagnetic reflection and scattering adjustment is realized.

The invention provides a determination method and device of a three-dimensional curled reflecting surface, equipment and a medium, is used for the field of electromagnetic reflecting surface calculation, and can solve the problem that the generation efficiency and accuracy of an existing three-dimensional curled reflecting surface are relatively low. Comprising the following steps: calculating index scores corresponding to a plurality of reflecting surface parameter groups, and determining an initial reflecting surface parameter group in the reflecting surface parameter groups; performing parameter crossing on different initial reflecting surface parameter groups to obtain target reflecting surface parameter groups, and performing iterative processing according to the index score corresponding to each target reflecting surface parameter group to obtain a to-be-designed reflecting surface parameter group; according to the to-be-designed reflecting surface parameter group, generating a two-dimensional curled edge reflection curve, and mapping sampling points on the two-dimensional curled edge reflection curve to obtain three-dimensional coordinate points; rotating the three-dimensional coordinate points, and connecting the rotated three-dimensional coordinate points to obtain a target three-dimensional curled edge reflecting surface; in this way, the generation efficiency and accuracy of the three-dimensional curled edge reflecting surface are improved.

An antenna system, comprising: an omni-directional antenna element; and a directional adapter having an electromagnetic reflector. The directional adapter detachably coupled to the omni-directional antenna element. The electromagnetic reflector being offset from the omni-directional antenna element. The directional adapter may be configured to be coupled to the antenna to convert a radiation pattern from an omni-directional antenna radiation pattern to a directional antenna radiation pattern, and configured to be decoupled from the antenna to convert the radiation pattern back into the omni-directional antenna radiation pattern.

A level determination system, for determining a level of a material interface in a tank, the level determination system comprising: a transceiver configured to generate, transmit, and receive electromagnetic signals; processing circuitry coupled to the transceiver, and configured to determine the filling level based on a timing relation between an electromagnetic transmit signal and an electromagnetic reflection signal resulting from reflection of the transmit signal at the material interface; and a signal propagation arrangement coupled to the transceiver, and configured to propagate the transmit signal from the transceiver towards the material interface and to propagate the reflection signal towards the transceiver, the signal propagation arrangement having a fluid absorbing surface portion, configured to absorb condensate.

The invention discloses a method for dynamically judging a perimeter alarm threshold value of a detection cable based on double-cable coupling, which relates to the technical field of perimeter alarm of the detection cable, and comprises the following steps of: on the basis of a frequency spectrum jump criterion set, calculating a consistency curvature of a main frequency scatter point track of a double-cable coupling signal, analyzing a ratio of periodic repetition term density to energy return, and calculating a threshold value of the perimeter alarm threshold value of the detection cable; judging whether the detection cable passes through the electromagnetic reflection structure or not; and under the condition that the detection cable passes through the electromagnetic reflection structure, relative slippage distribution of signal channels corresponding to the first cable and the second cable in the double-cable coupling signal on a frequency axis is extracted, and a feature vector set for describing spectrum dislocation features of the double-cable coupling signal is generated. According to the invention, the problem of alarm determination misalignment caused by frequency spectrum dislocation when a double-cable coupling detection cable passes through an electromagnetic reflection structure is solved, and accurate determination and adaptive dynamic regulation and control of a perimeter alarm threshold in a complex structure environment are realized.

An electromagnetically reflective surface device including a substrate comprising a first major surface and a second major surface opposite the first major surface, the first major surface having a plurality of RIS elements, each RIS element of the plurality of RIS elements including an outer annular electrically conductive ring concentric with a center point, a plurality of curved segments disposed between the outer ring and the center point, a pair of electrically conductive patches between the plurality of curved segments and the center point, and a bar segment positioned between straight edges of the pair of patches.

This invention discloses a wireless positioning method based on intelligent metasurface multipath suppression, belonging to the field of wireless communication technology. Addressing the problem of decreased positioning accuracy due to non-line-of-sight (NLS) disturbances in multipath environments, this invention utilizes the adjustable electromagnetic reflection coefficient of intelligent metasurfaces to actively reshape the wireless channel, achieving physical-layer destructive interference suppression of NLS paths. The method includes: deriving closed-form solution conditions for complete NLS path suppression based on orthogonal decomposition of the base station array response using discrete Fourier transform; constructing an optimization problem considering amplitude constraints, jointly adjusting the reflection coefficient of metasurface units to minimize NLS disturbance power; optionally, improving suppression accuracy through iterative channel estimation and metasurface configuration; and finally, achieving user positioning based on the purified line-of-sight dominant channel. This invention can effectively reduce the impact of multipath interference on positioning accuracy in complex propagation environments.

Provided are reaction vessels comprising: a) a reaction chamber; b) a thermal containment structure, the thermal containment structure comprising at least one thermally insulating body having a high specific heat capacity and shaped to reduce thermal conductivity between structures in the reactor vessel; and c) an electromagnetic wave containment structure, the electromagnetic wave containment structure comprising at least one electromagnetic-reflective body having a high melting point and a high recrystallization point, wherein the at least one electromagnetic-reflective body is shaped with a smooth innermost surface for maintaining electromagnetic waves in the reaction chamber.

The present disclosure provides a level determination system with reduced sensitivity to condensation. A level determination system (1) for determining a level of a material interface (13) in a tank comprises: a transceiver (19) configured to generate, transmit and receive electromagnetic signals; processing circuitry (21) coupled to the transceiver (19) and configured to determine a filling level based on a timing relationship between the electromagnetic transmit signal (ST) and an electromagnetic reflected signal (SR) resulting from reflection of the transmit signal (ST) at the material interface (13); and a signal propagation device coupled to the transceiver (19) and configured to propagate the transmit signal (ST) from the transceiver (19) towards the material interface (13) and to propagate the reflected signal (SR) towards the transceiver (19), the signal propagation device having a fluid absorbing surface portion (43) configured to absorb condensate (45).

The application discloses a RCS recovery and compensation calculation method based on flexible metal mesh equivalent surface reconstruction, which comprises the following steps: collecting the structure of the metal mesh, the test scene, the fitting state parameters and the measured RCS original data, and forming a standardized parameter database after preprocessing; adopting an adaptive density triangular division algorithm to disassemble the complex curved surface into triangular facets, constructing an electromagnetic reflection model for each triangular facet, correcting the electromagnetic coupling effect of adjacent facets, and integrating the complete equivalent reflection surface; dividing the system error and random error of the RCS measurement, establishing an error calculation model through electromagnetic theory derivation and experimental data fitting, and determining the weight through the entropy weight method; adopting a hybrid compensation strategy to compensate the system error, the random error and the curved surface reconstruction error, and verifying the recovery accuracy and the curved surface adaptability after outputting the accurate RCS data. The method greatly improves the RCS recovery accuracy, can well adapt to the complex curved surface of equipment, and meets the high-precision engineering test demand.

The application discloses aerogel with electromagnetic shielding function and a preparation method thereof, and relates to the technical field of aerogel materials, which comprises a silica aerogel matrix and a bacterial cellulose skeleton, the bacterial cellulose skeleton is dispersed in the silica aerogel matrix in a three-dimensional network shape, is covalently bonded and forms a hierarchical pore structure in the form of interpenetration. The hierarchical composite structure of the magnetic particles, the polydopamine intermediate layer and the conductive nanosheet loaded on the surface of the hierarchical pore skeleton layer by layer realizes the synergistic effect of conductive loss, magnetic loss and polarization loss, optimizes the impedance characteristics of the material, and mainly realizes efficient electromagnetic shielding performance by absorption loss, effectively reduces secondary electromagnetic reflection pollution, avoids functional filler falling off and performance attenuation, and guarantees the stability and reliability of the shielding performance in a long-term use process.

A radar sensor comprises an antenna layer with antenna elements, and a compound radome including an absorber layer on top of the antenna layer and a cover layer on top of the absorber layer. The absorber layer has a higher electromagnetic absorption than the cover layer. The compound radome comprises a primary region in which the absorber layer has a reference absorber thickness and the cover layer has a reference cover thickness, and a secondary region in which the absorber layer has a secondary absorber thickness and the cover layer has a secondary cover thickness. The secondary cover thickness is different from the reference cover thickness. An electromagnetic reflectivity is at a minimum within the primary region for a first incident angle and within the secondary region for a second incident angle being different from the first incident angle.

This invention discloses an electromagnetic shielding LCP thin film and its preparation method, relating to the field of liquid crystal polymer technology. The preparation method involves: plasma treatment of the surface of a single-sided copper-plated LCP substrate to activate the LCP surface; anchoring surface-modified zero-dimensional nanoparticles to polar sites on the substrate surface to form a dense bonding layer; subsequently introducing one-dimensional nanotubes embedded in the anchoring points and inducing their orientation under a specific coating method; finally, adding two-dimensional sheet materials to overlap and cover the one-dimensional filler, forming a complete and continuous network after coating. The thin film prepared by this invention exhibits stable electromagnetic shielding performance in the X-band and higher frequency bands, significantly outperforming single-sided copper-plated LCP thin films, and significantly improving the absorption loss ratio, thus mitigating electromagnetic reflection pollution. While possessing excellent electromagnetic interference protection capabilities, it fully retains the high-frequency signal transmission advantages of the LCP substrate.

A detection device for detecting an object under test, comprising a radar module, a waveguide element, and a first antenna element. The waveguide element is coupled to the radar module. The first antenna element is disposed on the waveguide element. The radar module is configured to generate a first electromagnetic incident wave, and the first antenna element is configured to emit the first electromagnetic incident wave toward the object under test. The first antenna element is further configured to receive a first electromagnetic reflected wave from the object under test, and the radar module is configured to process the first electromagnetic reflected wave. The first electromagnetic incident wave and the first electromagnetic reflected wave are configured to propagate through the waveguide element.