157 results about "Coaxial antenna" patented technology

An on-board radar apparatus includes an antenna unit configured by combining one of a lens and a reflector, and a plurality of antenna elements, a transmission and reception unit configured to emit a radio wave using, for at least one of transmission or reception, a partial antenna of a plurality of patterns configured by the antenna elements that are part of the plurality of antenna elements, and to receive a reflection wave obtained by reflection of the radio wave from an object, and a detection unit configured to detect the object based on the reflection wave received by the transmission and reception unit.

A semi-coaxial horn antenna transmits and receives electromagnetic waves, including impulse radio waves. The antenna includes an inner conductor that is surrounded by a cone-shaped dielectric, and an outer conductor that is conformally attached to the cone shaped dielectric. In embodiments, the inner conductor is a hollow metallic cylinder that is able to slide over a separate metal shaft, which may be part of a portable hand-tool device. The dielectric constant of the cone shaped dielectric may be selected to match a target medium. The outer conductor has a cross-section that is substantially an arc shape, and defines a sector angle phi that determines an impedance along the length of the antenna.

An improved antenna for microwave ablation uses a triaxial design which reduces reflected energy allowing higher power ablation and/or a smaller diameter feeder line to the antenna.

Apparatus for detecting vulnerable plaques embedded in the wall of a patient's blood vessel includes an intravascular catheter containing a microwave antenna, an extra-corporeal radiometer having a signal input, a reference input and an output, a cable for electrically connecting the antenna to the signal input, and a device for applying an indication of the patient's normal tissue temperature to the reference input so that when the catheter is moved along the vessel, the locations of the vulnerable plaques are reflected in a signal from the output as thermal anomalies due to the higher emissivity of the vulnerable plaques as compared to the normal tissue. A second embodiment of the apparatus has two coaxial antennas in the catheter serving two radiometers. One measures the temperature at locations in the vessel wall, the other measures the temperature at the surface. By subtracting the two signals, the locations of vulnerable plaque may be visualized. The apparatus employs a special diplexer for separating the signals from the two antennas and a method of detecting and possibly destroying the plaques is also disclosed.

An antenna for microwave tumor ablation provides coaxial antenna conductors surrounded by an insulated sleeve of length and size promoting destructive interference of axial microwave energy passing inside and outside of the sleeve to limit the tail of SAR power toward the skin.

An improved antenna for microwave ablation uses a triaxial design which reduces reflected energy allowing higher power ablation and/or a smaller diameter feeder line to the antenna.

This invention belongs to a laser radar domain, which relates to a continuous wave frequency modulation cohere laser radar which is on the basis of optical fiber laser device. Optical fiber laser device is used as light source, of which launching wnd links optical fiber coupler. Optical fiber coupler divides energy of light into two parts. Moiety is used as characteristics light, which can be directly inputted in an input end of secondary optical fiber coupler, the other part is inputted in expanding bunch lens device; after expanding bunch lens compresses laser emission angle, direct surveyed area by 2-dimensional scanner; echo-signal is feed-through one end of transmission optical fiber through optical antenna by 2-dimensional scanner, the other end of transmission optical fiber contacts secondary optical fiber coupler by optical fiber amplifier. After echo-signal and characteristics light are combined and interfered to mix frequency by optical fiber coupler, enter monitor component element. Monitor component element can transform and magnify signal photoelectricity, output, post it in computer by collecting card, carry out data processing. This invention has features of small volume, light quality, high integrated degree, good stability, intelligentification and modular.

The invention relates to a data transmission system for an underwater acoustic network, which comprises a plurality of independent underwater nodes, wherein each underwater node is equivalently connected with at least the other underwater node. The data transmission system also comprises a transmitting optical antenna, a receiving optical antenna, a light source, an optical modulator, an optical receiver, an underwater acoustic transducer/receiving transducer, a digital signal processor and a positioning module, wherein the positioning module is provided with a rotating device and used for completing the alignment between the light source and the optical receiver; the transmitting optical antenna, the light source, the optical modulator and the digital signal processor are in signal connection with each other in turn; the receiving optical antenna, the optical receiver and the digital signal processor are in signal connection with each other in turn; the digital signal processor is also in signal connection with the positioning module and the underwater acoustic transducer/receiving transducer respectively; and the light source is a blue-green laser source. The invention also relates to a data transmission method for the underwater acoustic network. The invention reduces the collision probability of data in the transmission process, improves the success rate of the construction of a communication link, saves the network bandwidth, and improves the network throughout.

The invention discloses a stable phase center measurement antenna which is mainly used in the fields of geodesy and relevant subjects including marine geodesy, geophysical exploration, resource exploration, engineering surveying, engineering deformation, spacecraft docking and the like. The antenna comprises a metal base of the antenna and wave-absorbing material arranged on the upper surface of the outer edge of the metal base. The center part of the metal base is a round cavity, and a circuit board protection cover, a multi-feed slot antenna array, a supporting medium, annular wave-absorbing material in the cavity, a coaxial feed antenna and a radio frequency connector are installed in the cavity from top to bottom. Two round groove choking coils are contained between the round cavity and the outer edge of the base. The multi-feed point, wave-absorbing material and coking coil technologies are comprehensively adopted for the stable phase center measurement antenna, and thus the stable phase center measurement antenna has the advantages of being low in wide angle polarization axis ratio and high in phase center stability and can be used for various kinds of precision measurement for satellite navigation.

A microwave charged particle source is provided according to various embodiments of the invention. The microwave charged particle source can include a coaxial antenna for generating microwaves and a dielectric layer surrounding the antenna. The microwave charged particle source can also include a first gas line outside the dielectric layer for providing sputtering gases and/or a second gas line for providing cooling gas in a space between the antenna and dielectric layer. The microwave charged particle source can further include a containment shield partially surrounding the dielectric layer and an extraction grid disposed on or near an aperture in the containment shield. In use, charged particles can be formed with the generated microwaves from sputtering gases. And the charged particles can be accelerated under an electric field created from a voltage applied to the extraction grid. A method for providing microwave charged particle source is also provided.

A coaxial antenna is implemented that combines a VHF and UHF antenna on a common radiating element. The antenna may further include a satellite antenna that, together with the VHF/UHF antenna fits into a whip antenna footprint.

The invention provides an optical antenna for multipoint laser communication and belongs to the technical field of a space laser communication. The optical antenna for multipoint laser communication provided by the invention comprises a multi-reflector splicing optical antenna with an APT (Automatically Programmed Tool) control system and a cassette beam contraction system. The optical antenna provided by the invention is constructed by improving the surface structure of a rotating paraboloid, and the laser communication of one point to multiple points at the whole periphery of the horizontal direction and in the design field angle of the pitching direction can be realized. Because the reflection is carried out by adopting laser beams received by a large-area plane reflector which is formed after multiple small-area plane reflectors are deflected, the optical antenna provided by the invention has higher energy utilization rate compared with the optical antenna with a continuous paraboloid; and simultaneously, the cassette beam contraction system is adopted to compress the diameter of the light beams which are received by a large-caliber optical antenna, thereby reducing the caliber of a subsequent system, reducing the manufacturing design difficulty and being beneficial to the miniaturization of an optical system.

The invention discloses an optical transmitting antenna system and a beam control method thereof. An optical antenna has an array structure which is formed by uniformly arranging a plurality of laser transmitting antennae and a plurality of receiving antennae. The array structure is arranged on a cambered surface (a hemispherical surface or a spherical surface). Each laser transmitting antenna comprises a transmitting multimode fiber and a transmitting micro-lens. Each receiving antenna comprises a receiving multimode fiber and a receiving micro-lens. A transmitting micro-lens is positioned in the center of each receiving micro-lens. By the optical transmitting antenna system and the beam control method thereof, the mobile communication of a near-earth atmospheric laser system is well realized, dependence on a complex acquisition pointing and tracking (APT) system is reduced, and communication reliability is improved.

The invention relates to a structured light projection diffractive optical device based on a superstructure surface, and belongs to the technical field of depth perception and optical imaging. The device provided by the invention consists of a substrate and a plurality of sub-wavelength optical antenna arrays arranged in a periodic form on the surface of the substrate, wherein the sub-wavelength optical antenna arrays are one-dimensional arrays or two-dimensional arrays; when the sub-wavelength optical antenna arrays are one-dimensional arrays, the respective optical antennas are wire grids arranged in the direction of a column and having rectangular or trapezoidal cross sections; when the sub-wavelength optical antenna arrays are two-dimensional arrays, the respective optical antennas arecylinders forming planes in the direction of a column and a row and having circular or arbitrary regular polygon shaped cross sections; in each of the sub-wavelength optical antenna arrays, the diameter of each optical antenna is 1/20 to 1/2 of the operating wavelength, the heights of the respective optical antennas are all equal and in the sub-wavelength range, and the center distances of the adjacent two optical antennas are both equal and not more than half of the operating wavelength. The device provided by the invention can realize structured light projection having a large diffraction angle, high diffraction efficiency, high uniformity and insensitive incident light polarization.

An antenna may include a ground plane and a solar cell spaced above the ground plane. The solar cell may have first and second power output terminals. The antenna may include a coaxial antenna feed line including an inner conductor coupled to the first power output terminal, and an outer conductor coupled to the ground plane so that the solar cell also serves as a patch antenna element. The antenna may further include a drive shunt conductor extending between the first terminal and the ground plane.

A biconical antenna driven by an equal-delay transformer is provided herein with a bifurcating ground plane. According to one embodiment, the biconical antenna comprises a pair of cone-shaped elements and a conducting ground plate. The cone-shaped elements are arranged back-to-back to one another and aligned along a first axis. The conducting ground plate is arranged between the cone-shaped elements in a plane perpendicular to the first axis. As described herein, the bifurcating ground plane provides the decoupling needed to eliminate the anomalous undulations, which tend to occur in the antenna response at odd-integer average quarter-wave frequencies.

The invention belongs to the field of communication technology, particularly relates to a mirror antenna used for compound communication of light wave and millimeter wave. The antenna comprises an antenna main mirror, a compound secondary mirror, an antenna canister and a millimeter wave guide, wherein the antenna main mirror and the compound secondary mirror are coaxially installed at the two ends of the antenna canister; the antenna main mirror is provided with a central light diaphragm; the millimeter wave guide tightly leans against the back of the compound secondary mirror; the center of the compound secondary mirror is provided with a rectangular area corresponding to a section of the millimeter wave guide; the concave side of the antenna main mirror is opposite to the front side of the compound secondary mirror; the front side of the compound secondary mirror and the focal plane of the antenna main mirror are superposed; the concave side of the antenna main mirror is plated with a reflective film for simultaneously reflecting laser and millimeter wave, and the area out of the rectangular area on the center of the front side of the compound secondary mirror is plated with a film for reflecting laser but transmitting millimeter wave. With small volume, light weight and low power consumption, the invention integrates the optical antenna for laser communication and the electric antenna for millimeter wave communication which can simultaneously perform the communication functions of laser light wave and millimeter wave.