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1013 results about "Surface wave" patented technology

In physics, a surface wave is a 90 degree wave that propagates along the interface between differing media. A common example is gravity waves along the surface of liquids, such as ocean waves. Gravity waves can also occur within liquids, at the interface between two fluids with different densities. Elastic surface waves can travel along the surface of solids, such as Rayleigh or Love waves. Electromagnetic waves can also propagate as "surface waves" in that they can be guided along a refractive index gradient or along an interface between two media having different dielectric constants. In radio transmission, a ground wave is a guided wave that propagates close to the surface of the Earth.

Magnetic-acoustic surface wave magnetic field sensor and preparation method thereof

The invention relates to a magnetic-acoustic surface wave magnetic field sensor and a preparation method thereof, and belongs to the technical field of electronic functional materials and devices. The sensor comprises a piezoelectric thin film, a magnetostrictive thin film and a substrate, wherein the magnetostrictive thin film is positioned between the piezoelectric thin film and the substrate; the thickness of the magnetostrictive thin film is 2-5 times the thickness of the piezoelectric thin film; and an interdigital transducer is arranged on the surface of the piezoelectric thin film, and the interdigital transducer and the piezoelectric thin film constitute an acoustic surface wave device. A layer of SiO2 is covered on the surface of the piezoelectric thin film and the interdigital transducer. When the sensor is in resonant state, if an external magnetic field changes, the Young's modulus of a magnetostrictive layer changes, the propagation speed of acoustic surface waves in a piezoelectric layer can be further affected and then the changes of the external magnetic field can be known by detecting the changes in resonance center frequency. The SiO2 covering layer can compensate for a frequency temperature coefficient of the piezoelectric thin film and realize the frequency temperature coefficient which is close to zero. The sensor has the characteristics of miniaturization, easiness in integration, high sensitivity, good consistency, stability and reliability.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Circularly Polarized Antenna and Radar Device Using the Same

A circularly polarized antenna has a dielectric substrate, a ground conductor which is piled up one surface side of the dielectric substrate, a circularly polarized type of antenna element formed on an opposite surface of the dielectric substrate, a plurality of metal posts whose respective one end sides are connected to the ground conductor and penetrate the dielectric substrate along a thickness direction thereof, and whose respective other sides extend up to the opposite surface of the dielectric substrate, the plurality of metal posts configuring a cavity by being provided at predetermined intervals so as to surround the antenna element, and a conducting rim which short-circuits the respective other end sides of the plurality of metal posts along an array direction thereof, and is provided so as to extend by a predetermined distance in a direction of the antenna element at the side of the opposite surface of the dielectric substrate. With the circularly polarized antenna, a radiation characteristic of the antenna can be made to be a desired characteristic by preventing a surface wave from being generated by means of the cavity and the conducting rim, and a frequency characteristic of the antenna gain can be made to have a sharp notch within the RR prohibited band by utilizing a resonance of the cavity. Accordingly, the circularly polarized antenna is effective for reducing radio interference with the EESS or radio astronomical services.
Owner:ANRITSU CORP +1

Ferrite-base composite magnetic dielectric antenna substrate material and preparation method thereof

The invention discloses a ferrite-base composite magnetic dielectric antenna substrate material and a preparation method thereof. The ferrite-base composite magnetic dielectric antenna substrate material is formed by combining a main phase material which accounts for 85-90wt% and an auxiliary phase material which accounts for 15-10% in percentage by mass, wherein the main phase material is Co2Z type hexagonal ferrite, with molecular formula represented as Ba3-xSrxCo2Fe24-yO41, wherein x ranges from 0 to 1.5 and y ranges from 0 to 4; the auxiliary phase material is polyimide resin. The magnetic dielectric composite substrate material has a relatively low magnetic conductivity and a relatively high dielectric constant within a frequency range of 300MHz-3GHz, and the composite substrate material is comparatively high in miniaturization factor and is simultaneously comparatively low in both magnetic loss and dielectric loss; the composite substrate material, in comparison with the conventional ceramic substrate material, is better in mechanical shock resistance. The ferrite-base composite magnetic dielectric antenna substrate material is not only favorable for reducing the weight and size of an antenna, but also conductive to improving the bandwidth of the micro-strip antenna and for inhibiting the generation of a surface wave.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA
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