2619 results about "Double frequency" patented technology

A low-profile dual-band antenna includes a ground plane. An “E”-shaped metal plate is located a first distance from the ground plane and includes first and second outer extensions and an inner extension of the metal plate. A feed tab connects the inner extension and the ground plane. A shorting tab connects the inner extension and the ground plane. The low-profile dual-band antenna communicates first radio frequency (RF) signals in a first RF band and second RF signals in a second RF band. The first RF signals and the second RF signals are vertical polarized signals. The low-profile dual-band antenna produces a radiation pattern that is omnidirectional in the azimuth plane and vertically polarized in a horizontal plane when communicating the first RF signals and the second RF signals. The first RF band and the second RF band can be independently tuned.

A biometric identification system directed toward use of dual-band visual-infrared imaging with appropriate techniques for integrating the analysis of both images to distinguish less reliable from more reliable image components, so as to generate a composite image comprised of layers. Correlation and analysis of the composite layers enables improved reliability in identification. The method and apparatus of the invention provide for efficient and optimized use of dual-band imaging for biometric identification of faces, fingerprints, palm and hand prints, sweat pore patterns, wrist veins, and other anatomical features of humans and animals.One embodiment includes the addition of a thermal infrared camera to a visual facial recognition system, with the IR image used to determine that the subject is alive and locate any features which are disguised. Another embodiment adds a visual camera to a thermal infrared facial recognition system, with areas of the visual image used to add colors and to fill-in behind eyeglasses which block the thermal infrared signature.

A high-frequency circuit for use in a dual-band wireless communications apparatus selectively using first and second frequency bands, comprising a diplexer connected to the output of a power amplifier for sending either one of transmission signals in the first and second frequency bands to an antenna, a coupler having a primary line connected to a common end of the diplexer and a secondary line, a detector comprising a detection diode for detecting a transmission power of a high-frequency signal sent from the secondary line of the coupler, and a harmonics-suppressing circuit disposed between the secondary line of the coupler and the detection diode.

The invention relates to a dual-band inverted-F antenna with shorted parasitic elements. The antenna of the invention comprises a ground plane, a first radiating arm placed above an edge of the ground plane, a second radiating arm placed above the edge of the ground plane, a shorting arm with a substantially inverted-L shape for electrically connecting the first radiating arm and the second radiating arm to the ground plane, a shorted parasitic arm placed above the edge of the ground plane, and a feeding coaxial cable for transmitting signals. There is a distance between the shorted parasitic arm and the first radiating arm so as to induce extra capacitive reactance to compensate the inductive reactance induced by inserting the feeding coaxial cable. The present invention is suitable for the wireless local area network (WLAN) applications in the 2.4 GHz (2.4–2.484 GHz) and 5 GHz (5.15–5.35, 5.725–5.875 GHz) bands.

A Parasitic Element (202) for use in combination with a Planer Inverted “F” Antenna (PIFA) (100) that creates an additional band of efficient operation for the combined antenna structure (200). The parasitic element (202) is able to be made to conform to surfaces (704) that are near the PIFA, such as of a case (704) of a cellular telephone (706). The parasitic element (202) is positioned so as to radiantly couple with the PIFA (100) in order to create the additional band of efficient operation. A parasitic element (202) is used with a dual band PIFA that operates in two RF bands, such as in the region near 800 MHz and 1.9 GHz, and adds a third band such as in the region near 1.575 GHz to support reception of Global Positioning System signals. This parasitic element (202) can conform to a case (704) of the cellular telephone (706).

The invention discloses a double-frequency grating interferometer displacement measurement system. The system comprises a double-frequency laser device, an interferometer, a measuring grating and an electrical signal processing portion. The measurement system achieves displacement measurement based on optical grating diffraction, the optical doppler principle and an optical beat frequency principle. The double-frequency laser device transmits double-frequency laser, the laser is divided into reference light and measuring light through a polarizing beam splitter, the measuring light transmits into a position of the measuring grating, positive and negative first-order diffraction occurs, diffraction light and the reference light form a beat frequency signal which contains displacement information in two directions at the position of a light detection unit, and linear displacement output is achieved through signal processing. According to the system, the sub-nanometer-grade or even higher grade of resolution ratio and accuracy can be achieved, and horizontal large-stroke displacement and horizontal displacement can be measured at the same time. The system has the advantages of being insensitive to the environment, high in measuring accuracy, small in volume and light in weight. The system serves as a lithography machine ultraprecise workpiece platform position measurement system, the comprehensive performance of the workpiece platform can be improved.