3 results about "Tm waves" patented technology

The invention discloses a Janus antenna array device and method for realizing one-way near-field coupling of a coupling surface. More flexible near-field directional excitation of light is realized. The device of the Janus antenna array for realizing the unidirectional near-field coupling of the coupling surface comprises a feed network structure and an outer coupler, the outer coupler comprises two dielectric waveguides which are parallel to each other, and the two dielectric waveguides are arranged at an interval to form an assembly space; the feed network structure comprises a feed network and a plurality of Janus antennas based on Janus dipoles, the Janus antennas are connected to the feed network, the Janus antennas are arranged in the assembly space in an array mode, each Janus antenna is provided with an electric dipole and a magnetic dipole, and the electric dipoles and the magnetic dipoles are perpendicular to each other and have phase differences. The magnetic dipoles correspond to the width direction of the assembly space, and the electric dipoles correspond to the length direction of the assembly space so as to excite quasi-TM waves in the dielectric waveguide.

The application provides a kind of wideband wide-angle wave absorber based on three-dimensional frequency selective surface, comprising a plurality of three-dimensional frequency selective surface units with same structure and continuous arrangement, each three-dimensional frequency selective surface unit is a hollow cuboid, and each three-dimensional frequency selective surface unit comprises horizontal structure, vertical structure and metal bottom plate arranged in sequence from top to bottom; the wave absorber provided by the application can significantly improve the angle stability of the wave absorber by combining the horizontal structure with the vertical structure, and for 0-60° oblique incidence of TE and TM waves, more than 90% absorption can be achieved within 2.1 times the frequency bandwidth; meanwhile, the wave absorber in the application has the advantages of low profile, small thickness and period size, is easy to integrate with other devices, and is high in convenience; in addition, a center-symmetric pattern design is used in each layer structure of the frequency selective surface unit in the application, which reduces the polarization direction sensitivity of the wave absorber to incident electromagnetic waves.

The invention discloses a cased well ground signal two-way wireless electromagnetic transmission device and method, and belongs to the technical field of oil and gas field development logging, the cased well ground signal two-way wireless electromagnetic transmission device comprises an underground terminal system, a metal loop transmission channel and a ground terminal system, the metal loop transmission channel is a closed metal loop constructed with an oil pipe and a casing as carriers, and the metal loop transmission channel is a closed metal loop. The underground terminal system is sequentially and electrically connected with a first centralizer, an ascending transmission short section, a packer, a descending transmission short section, a sensor integration short section and a second centralizer from top to bottom along the axis of a casing pipe, and the first centralizer and the second centralizer are made of conductive rubber materials. The oil pipe and the sleeve are electrically conducted to construct the closed metal loop, the oil pipe and the sleeve serve as carriers to construct a closed metal loop transmission channel, transmission media do not need to be additionally laid, the metal loop provides a low-loss transmission path for TM waves, signal attenuation is effectively reduced, and the transmission efficiency is improved. The problem of serious signal attenuation in a deep well in traditional wireless electromagnetic transmission is solved.