摘要:
Two optical fibers are spliced together to form a single spliced optical fiber. The spliced region is uncontaminated by impurities, and has substantially no loss of optical transmission or mechanical strength as compared to the other regions of the fibers. Splicing is accomplished by removal of the buffer coating, if any, cleaving of the fibers to be spliced to form facing splicing surfaces, careful precleaning of the cleaved fibers in the region adjacent the splicing surfaces, aligning the fibers using optical transmission as the alignment criterion, fusing the fibers together by preheating the region to be spliced, fusing the region, postannealing the spliced region, carefully postcleaning the spliced region, and recoating the spliced region with a UV curable polymer buffer material, if desired. The heating of the fibers to accomplish the fusion is desirably accomplished by a laser such as a carbon dioxide laser.
摘要:
Apparatus for a micro-electro-mechanical switch that provides single pole, double throw switching action. The switch has two input lines and two output lines. The switch has a seesaw cantilever arm with contacts at each end that electrically connect the input lines with the output lines. The cantilever arm is latched into position by frictional forces between structures on the cantilever arm and structures on the substrate in which the cantilever arm is disposed. The state of the switch is changed by applying an electrostatic force at one end of the cantilever arm to overcome the mechanical force holding the other end of the cantilever arm in place.
摘要:
A control system and method for controlling switching between and among multiple antennas in a diversity antenna system comprising a radio head unit associated with a radio receiver; two or more antennas, either located in separate antenna modules or co-located in the same antenna module; a switch circuit; and a single cable. Control signals for controlling switching are provided as changes in a DC power supply signal carried on the single cable. In the case of multiple antenna modules, the radio head unit and the antenna modules are connected by the single cable using a daisy-chain architecture.
摘要:
One or more of the embodiments of a dual band stacked patch antenna described herein employ an integrated arrangement of a global positioning system (GPS) antenna and a satellite digital audio radio service (SDARS) antenna. The dual band antenna receives right hand circularly polarized GPS signals in a first frequency band, left hand circularly polarized SDARS signals in a second frequency band, and vertical linear polarized SDARS signals in the second band. The dual band antenna includes a ground plane element, an upper radiating element (which is primarily utilized to receive SDARS signals), dielectric material between the ground plane element and the upper radiating element, and a lower radiating element (which is primarily utilized to receive GPS signals) surrounded by the dielectric material. The dual band antenna uses only one conductive signal feed to receive both GPS and SDARS signals.
摘要:
A method for improving the efficiency of antennas having transparent thin-film conductive surfaces, and antennas improved by the method are disclosed. For a selected frequency of antenna operation, values for surface current density in areas distributed over the surface of the thin-film are determined. Regions of the surface containing areas having concentrated current flow are identified based upon the determined values of current density. Antenna efficiency is improved by increasing conductivity in areas of the thin-film surface found to have concentrated current flow. The method enables the improvement of the efficiency of antennas having transparent thin-film conducting surfaces, without unnecessarily obstructing the optical view through the thin-film surfaces of the antennas.
摘要:
An onboard wireless communication system for a vehicle, such as a tire pressure monitoring system (“TPMS”) is disclosed. The TPMS includes wheel-mounted radio frequency (“RF”) sensor/transmitters that transmit RF signals conveying tire pressure information, at least one RF relay element, and an RF receiver coupled to a TPMS processor. The RF relay element(s) relay the RF signals from the sensor/transmitters to the RF receiver to reduce the negative effect of electromagnetic field scattering caused by conductive parts of the vehicle.
摘要:
An integrated multi-beam antenna with a shared dielectric lens is disclosed. The antenna is formed by positioning the feed apertures of a plurality of waveguide feeds at positions located on the surface of the shared dielectric lens. The angular direction and shape of radiation beams produced by the waveguide feeds are determined by the physical and dielectric characteristics of the lens, the location of feed apertures of the waveguide feeds on the surface of the lens, and the frequency of electromagnetic energy propagating in the waveguide feeds. The principles of the invention are applied to realize an inexpensive, integrated multi-feed antenna adapted to provide desired angular areas of coverage for both a long range and short range radar in an automotive radar safety system.
摘要:
An anisotropic reactive frequency selective surface (FSS) ground plane for controlling the beam pattern of an antenna. More specifically, the ground plane comprises a plurality of FSS unit cells arranged in an elongated shape and operable to control the beam pattern of the antenna in at least two orthogonal directions. The ground plane may be incorporated into a system including a vehicle windshield and the antenna, and is mounted at, or embedded in, a top-center portion of the windshield, substantially centered on the antenna. In this system, the orthogonal directions include a first direction that is substantially parallel to a road surface on which the vehicle travels, and a second direction that is substantially perpendicular to the first direction and that grazes a sideward surface of the windshield
摘要:
A method for improving the efficiency of antennas having transparent thin-film conductive surfaces, and antennas improved by the method are disclosed. For a selected frequency of antenna operation, values for surface current density in areas distributed over the surface of the thin-film are determined. Regions of the surface containing areas having concentrated current flow are identified based upon the determined values of current density. Antenna efficiency is improved by increasing conductivity in areas of the thin-film surface found to have concentrated current flow. The method enables the improvement of the efficiency of antennas having transparent thin-film conducting surfaces, without unnecessarily obstructing the optical view through the thin-film surfaces of the antennas.
摘要:
The radiation properties and wave guiding properties of frequency selective surfaces are used in conjunction with closely spaced antenna elements to fabricate antenna structures having adjustable radiation characteristics. The direction, magnitude, and polarization of radiation patterns for such antenna structures can be adjusted by varying the texture or patterning of layers of conducting material forming the frequency selective surfaces. The invention enables the fabrication of low profile antenna structures that can easily be conformed or integrated into complex surfaces without sacrificing antenna performance.