Reflector (antenna)

About: Reflector (antenna) is a research topic. Over the lifetime, 28730 publications have been published within this topic receiving 212618 citations.

Multi-layer dispersion-engineered waveguides and resonators

Abstract: A multi-layer laterally-confined dispersion-engineered optical waveguide may include one multi-layer reflector stack for guiding an optical mode along a surface thereof, or may include two multi-layer reflector stacks with a core therebetween for guiding an optical mode along the core. Dispersive properties of such multi-layer waveguides enable modal-index-matching between low-index optical fibers and/or waveguides and high-index integrated optical components and efficient transfer of optical signal power therebetween. Integrated optical devices incorporating such multi-layer waveguides may therefore exhibit low (<3 dB) insertion losses. Incorporation of an active layer (electro-optic, electro-absorptive, non-linear-optical) into such waveguides enables active control of optical loss and/or modal index with relatively low-voltage/low-intensity control signals. Integrated optical devices incorporating such waveguides may therefore exhibit relatively low drive signal requirements.

Deployable antenna with 10-m maximum diameter for space use

Abstract: This paper describes a large deployable antenna which is used at L-, C-, and Ka-bands on an artificial satellite in space. The main reflector with 10-m maximum diameter is formed using the tensioned truss concept which was proposed by one of the authors. The mechanical structure of the antenna is briefly explained and a more detailed description given of the electrical design of the antenna and the verification method of electrical characteristics. This antenna was successfully launched and deployed in space in 1997 and is used for a Space VLBI mission.

Reflector antenna radiation pattern analysis by equivalent edge currents

Abstract: Equivalent edge currents, derived from the edge diffraction theory for a half-plane, are used to obtain the radiation patterns of a parabeloidal reflector antenna when illuminated by a source at the focus. Cylindrical wave diffraction coefficients are used. The method avoids infinities at caustics and shadow boundaries thus giving solutions which are finite everywhere. A slope-wave equivalent current correction term is applied when the illumination is tapered towards the edge of the reflector. Comparisons are given with the physical optics approach and experimental results.

Electronically steerable parasitic array radiator antenna for omni- and sector pattern forming applications to wireless ad hoc networks

Abstract: An electronically steerable parasitic array radiator antenna is presented. The antenna has only a single element connected to a receiver or a transmitter. This active element is surrounded by parasitic elements loaded with variable reactors (varactors). The loaded reactance and the length of the parasitic radiators are designed so that each of the parasitic elements plays its role of director or reflector depending on its bias voltage on the loaded reactance. This design guarantees that the radiation pattern can be controlled by changing the bias voltages on the varactors. For omnipattern forming, a voltage vector is obtained such that the received power is maximised under the assumption that each component of the voltage vector is equal. An experiment yields an omnipattern with an average −0.83 dBi gain over the angles [0°, 360°). For sector pattern forming, a single-source power maximisation technique is proposed to optimise the voltage vector such that the received signal power is as large as possible in the direction of the source. Experiments yield twelve sector patterns at every 30°. The average gain is 5.5 dBi in the patterns' beam directions. The average 3 dB beamwidth is 72.4° for the sector patterns in the directions 0°, 60°, 120°, 180°, 240°, and 300°, while the average value is 90.1° for the remaining patterns.

Antenna assembly for satellite and wireless services

Abstract: An antenna assembly includes a reflector dish and a unit attached at a distal end of an arm to receive satellite signals reflected from the reflector dish. The unit includes at least one low-noise block converter (LNB) to receive the satellite signals and a wireless communication transceiver that operates to transmit and receive video and data information within a surrounding range.