1225 results about "Cross polarization" patented technology

The invention provides a Ku/Ka frequency band circularly polarization integrated receiving and transmitting feed source antenna applied to antenna systems, such as a paraboloid antenna and the like, in satellite communication. The antenna adopts a coaxial nested compact structure, and is applied to Ku frequency band and Ka frequency band at the same time. The basic structure of a feed source comprises a circular waveguide, on which a pointed cone shaped dielectric rod is loaded, a flange, a coaxial waveguide, a symmetrical SMA connector pair, a circular polarizer and an orthogonal mode coupler, wherein the feed source in the Ka frequency band is applied to dual circular polarization, has rotary symmetrical radiation directional diagrams, the circularly polarization axial ratio in Ka double band is smaller than minus 2dB, and the transmitter-receiver isolation is smaller than minus 70dB; and the feed source in the Ku frequency band is applied to dual circular polarization, has rotary symmetrical radiation directional diagrams, a cross polarization level smaller than minus 40dB, and good transmitter-receiver isolation and reflection loss.

An ultra-wideband magnetic antenna includes a planar conductor having a first and a second slot about an axis. The slots are substantially leaf-shaped having a varying width along the axis. The slots are interconnected along the axis. A cross polarized antenna system is comprised of an ultra-wideband magnetic antenna and an ultra-wideband dipole antenna. The magnetic antenna and the dipole antenna are positioned substantially close to each other and they create a cross polarized field pattern. The present invention provides isolation between a transmitter and a receiver in an ultra-wideband system. Additionally, the present invention allows isolation among radiating elements in an array antenna system.

A half-wave printed “patch” antenna includes, symmetrically with respect to a plane of symmetry of the antenna perpendicular to faces of the antenna, a dielectric substrate and two conductive layers on respective faces of the substrate. One face of the substrate includes a raised portion extending lengthwise of the plane of symmetry and one of the conductive layers extends over and along said raised portion. Consequently, the antenna has a small size, combined with a more open radiation diagram. The antenna includes only one raised portion for linear polarization, or two raised portions or a raised portion with axial symmetry for crossed polarizations.

Techniques are described for modeling layered facial reflectance consisting of specular reflectance, single scattering, and shallow and deep subsurface scattering. Parameters of appropriate reflectance models can be estimated for each of these layers, e.g., from just 20 photographs recorded in a few seconds from a single view-point. Spatially-varying specular reflectance and single-scattering parameters can be extracted from polarization-difference images under spherical and point source illumination. Direct-indirect separation can be employed to decompose the remaining multiple scattering observed under cross-polarization into shallow and deep scattering components to model the light transport through multiple layers of skin. Appropriate diffusion models can be matched to the extracted shallow and deep scattering components for different regions on the face. The techniques were validated by comparing renderings of subjects to reference photographs recorded from novel viewpoints and under novel illumination conditions. Related geometry acquisition systems and software products are also described.

Methods and apparatus are described that provide the ability to estimate the diffuse reflection component of an image of tissue such as skin captured without cross-polarization. It is thereby possible to estimate skin pigmentation information from an image of skin captured conventionally, such as, for example, a total reflection image, obtained in a conventional manner by shining white light on the skin and capturing the reflected light. The image may also be a partially diffuse reflection image, such as a low quality cross-polarized image. The diffuse reflection component of a captured image can then be further processed to obtain Red and Brown pigmentation images, useful for indicating the distribution of hemoglobin and melanin, the primary chromophores of skin. Additionally, a standard captured image of skin can be analyzed to obtain an estimate of the surface reflection component of the reflected light. The surface reflection component can then be used to generate a surface reflection image, useful for showing the distribution of light on the skin and to highlight superficial features such as wrinkles, fine lines, folds, pores, texture, and visible spots.

A dual-polarized patch antenna, an dual-polarized patch antenna array, and a method for forming the same are provided. The dual-polarized patch antenna comprises a radome, a horizontal feed and a vertical feed, a first cross-shaped patch, and a ground plane including a cross aperture. The dual-polarized patch antenna may include a cross patch and a cross aperture to increase the isolation in a cross-polarization between a horizontal polarized signal and a vertical polarized signal in a first principle plane and to decrease a mismatch in co-polarizations between the horizontal polarized signal and the vertical polarized signal in a second principle plane.

A digital imaging system provides color information of an entire port wine stain or other skin condition with a single image in CIE L*a*b* color space (L*, a*) derived from RGB pixel data (R, G, B). Cross-polarization optics produce marked reduction in specularly reflected light in the images. A patient positioning device allows for repeatable positioning of the patient's head or body portion. The digital nature of the system provides a near real-time mapping of melanin and erythema or other skin chromophore metrics. The cross-polarized diffuse reflectance color digital imaging system obtains subsurface skin color information and acquisition of facial images in a reproducible fashion at a fixed distance from an illumination source at optimized angles of view depending on the region of interest being imaged.

A dual channel redundant wireless network link formed by the Redundant Fixed Wireless Network Link device 10 of the present invention provides a very high reliable network element for mission critical wireless network application. Redundant Fixed Wireless Link device (10) with two wireless networking radio channel (11, 12) turned on simultaneously, and running networking service feature is working as Service Equipment (SE). Both wireless networking radio channel (11, 12) of the SE have the same directional wireless network coverage area. The two wireless networking radio channels (11, 12) are separated by cross polarization of antenna at same radio frequency, or different radio frequency characteristics. One Redundant Fixed Wireless Link device (10) with one of its two wireless networking radio channel (11, 12) turned on and communicating with said SE, and loaded with networking client feature is acting as Client Equipment (CE). The link quality monitor feature of the CE is monitoring the communication link between the SE and CE. When the current link quality is low or the link is down, the CE automatically switches on the alternate wireless networking radio channel (11, 12) to maintain the network communication between the SE and CE. One SE may communicate with plurality of CE in the same wireless network coverage area.

Substantial improvements in frequency reuse in microwave communications systems is achieved by canceling co-channel interference and transmitter leakage. Interferometric beam-narrowing reduces beamwidth without reducing preak magnitude of the beam pattern. Frequency-dependent beam-shaping compensates for frequency-dependent distortions of the beam pattern thereby improving bandwidth. A spatial demultiplexing technique utilizes spatial gain distributions of received signals to separate signals, even from co-located transmit sources, and uses microwave lensing to enhance received spatial gain distributions. Predetermined cross-polarization interference is used to separate differently polarized receive signals. A reference branch provides a cancellation signal to a receiver to cancel transmitter leakage signals. An error signal controls an impedance-compensation circuit that is responsive to changes in antenna impedance but not to receive signals. A dc bias magnetic field applied to a magnetic permeable material adjusts non-linear distortion in a cancellation circuit for canceling distortion in a transmitter leakage signal. Discreet impedance elements approximate a circuit having distributed impedance.

The invention provides a dual-polarized vibrator unit, an antenna and a multi-frequency antenna array. The dual-polarized vibrator unit includes a radiator and a balun support portion for feeding of the radiator. The radiator includes a dielectric substrate, two pairs of dipole antenna arms being disposed on an upper surface of the dielectric substrate and in orthogonal arrangement of plus or minus 45 degrees, and at least one coupling metal strap disposed on a lower surface of the dielectric substrate. Current induction is generated between the dipole antenna arms and the coupling metal strap so that a current path is formed on the coupling metal strap. The vibrator unit and the antenna thereof in the invention can achieve the ultra-broadband, high gain, high efficiency, high cross polarization ratio and high front-ratio, high isolation, low profile and low coupling and is simple and beautiful in structure, easy in engineering realization and suitable for mass production, the production cost is reduced, and the electrical performance index meets the base station antenna industry standard.

A complementary wideband antenna includes a planar dipole formed of two dipole sections and a shorted patch antenna located between the dipole sections, the dipole sections being spaced above a ground plane. A variety of different feed probe designs can be used to excite the antenna. The complementary wideband antenna has electrical characteristics including low back radiation, low cross polarization, a symmetrical radiation pattern, and is stable in gain and radiation pattern shape over the frequency bandwidth.

An all outdoor unit communication system, for performing cross polarization interference cancellation, is provided. The system includes a first outdoor unit (ODU) configured to receive a horizontally polarized signal, a first RF module configured to convert the horizontally polarized signal into a first in-phase (I) component and a first quadrature (Q) component, and a first modem configured to up-convert the first I and Q components from baseband into a horizontally polarized intermediate frequency (IF) signal. The system also includes a second ODU configured to receive a vertically polarized signal, a second RF module configured to convert the vertically polarized signal into a second I component and a second Q component, and a second modem configured to up-convert the second I and Q components from baseband into a vertically polarized IF signal. The system is configured to share, via an interconnect, the polarized IF signals between the first and second ODUs.

The invention provides a radial element structure of a broadband bipolarized antenna, which comprises a surface radiation unit, a medium plate, a feeding support and a reflecting plate; the surface radiation unit comprises array arms of semi-wave arrays; the feeding support is positioned between the medium plate and the reflecting plate; the invention also comprises a parasitic structure which is arranged at the bottom end of the array arm of the surface radiation unit to allow two adjacent array arms to be in capacitive joint; and the surface radiation unit and the parasitic structure are adhered on two sides of the medium plate respectively. The radial element structure can improve the balance of the arrays, effectively improves the crossed polarization property and strengthens the directivity of radiation in the direction of +/-60 degrees; and the radial element structure improves the back wave loss and the isolation degree of the arrays. The radial element structure has a more stable and reliable structure and is easier to be rapidly assembled and welded as an independent part.

A receiver includes an input circuit, which is coupled to at least one antenna so as to receive, process and digitize first and second signals, thus generating first and second streams of input samples. An interference cancellation circuit in the receiver includes first and second adaptive filters, which are respectively coupled to filter the first and second streams of input samples using respective first and second coefficients to generate respective first and second filter outputs. A phase rotator is adapted to apply a variable phase shift compensating for a phase deviation between the first and second signals, the phase rotator having at least one configuration parameter. A control module is operative to estimate signal characteristics of the interference cancellation circuit and to set the at least one configuration parameter of the phase rotator responsively to the estimated signal characteristics.

The invention discloses a dual-polarized filter antenna with high selectivity and low cross polarization. The dual-polarized filter antenna comprises a metal reflecting floor at the bottom part, a middle feed patch, a parasitic patch at the top part, a first dielectric substrate, a second dielectric substrate and two sections of feed lines, wherein the parasitic patch is printed on the upper surface of the first dielectric substrate; the feed patch is printed on the upper surface of the second dielectric substrate; and the two sections of feed lines are orthogonally coupled and are printed on the lower surface of the second dielectric substrate. The feed structure disclosed by the invention can generate one zero point at a passband low-frequency band of the antenna; meanwhile, the designed parasitic patch generates one zero point at a passband high-frequency band; and the two zero points provide good band-pass filtering and frequency selectivity effects.

The invention relates to a microstrip patch antenna with a reconfigurable directional diagram, which belongs to the technical field of antennae. The microstrip patch antenna comprises a metal ground plate on the lower surface of a dielectric plate and a radiation patch on the upper surface of the dielectric plate, wherein the radiation patch consists of a square main radiation patch unit and four appended patch units with same distances from four directions of the square main radiation patch unit; each appended patch unit consists of two rectangular patches connected by an electronic switch; and each electronic switch is respectively controlled by a switch controller. Different switch combinations control different appended patches to perform energy radiation so that a plurality of directional diagrams with multiple working modes can be realized. Meanwhile, the invention has the characteristics of little cross polarization, small size and high gain. The microstrip patch antenna is applicable to different antenna arrays to realize beam forming and scanning.