Dual reflector antennas are considered as pencil beam antennas that can produce radiation identical to searchlight. Cassegrain Reflector Antenna Design consists of various effects caused by blockage by primary feed or by the subreflector and its effect on overall performance. The objective of the paper is to provide the overview of the designing approach that is used to design the axially symme...

we present a detailed analysis of the static tuning characteristics of three section tunable distributed bragg reflector (dbr) laser. the analysis is based on the transfer matrix method (tmm), transmission line and scattering theory. the key feature of the analysis is the use of modified oscillation condition. with the exact oscillation condition, the static tuning characteristics such as thres...

This paper is concerned with the design of a new type of multi-purpose deployable membrane reflector. The reflector structure consists of a central expandable hub, a number of thin-walled foldable ribs connected radially to the hub, and a precision-shaped membrane supported and tensioned by the ribs. This concept is known as a collapsible rib-tensioned surface reflector. A methodology for the d...

A polarization-enhancing reflector design, which is matched to the emission characteristics of GaInN/GaN 460 nm light-emitting diodes grown on (0001) oriented sapphire substrates, is reported. Side-emitted light from these devices is known to be highly polarized with the electric field in the plane of the active region. Through selective rotation of polarization by the reflector, the in-plane p...

Since radio telescope is the main tool for human being to search the universe secret, the astronomer reached unanimity at the 24th URSI Conference in Kyota, Japan, 1993, and proposed to construct the next generation of the large radio telescope (LT) (Nan & Peng, 2000). From then on, the astronomer of China began the project of Five-hundred meter Aperture Spherical radio Telescope (FAST) (Qiu, 1...

Cost effective, new antenna technology is required to build the large collecting area being planned for the next generation of radio telescopes. The Large Adaptive Reflector (LAR) is a novel concept being developed in Canada to meet this challenge. A prototype with a 200-350m diameter reflector, operating up to 2 GHz with a bandwidth of 750 MHz is planned. With a collecting area up to ∼ 10% of ...

A silicon metal–semiconductor–metal photodetector with high-efficiency and high-speed in the infrared is reported. The high performance is achieved by using a Si-on-insulator substrate with a patterned nanometer-scale scattering reflector buried underneath a 170-nm-thick Si active layer. This scattering reflector causes light to be trapped inside the thin Si active layer, resulting in a fast an...

In this paper, a directional GPS antenna for L1 frequency 1575 MHz with RHCP and a high directive gain is proposed for indoor positioning applications. The proposed antenna is made of a standard off the shelf GPS patch antenna with an additional conical reflector to enhance the gain and the beamwidth of the antenna. The angle of the cone reflector is optimized by HFSS 11 software. Finally, the ...

Tiger beetles of the genus Cicindela exhibit iridescent structural coloration due to the presence of a non-ideal multilayer interference reflector located in the outermost 2 ̂ m of the integument. The reflector is composed of alternating layers of electron-lucent and electron-dense material. This series of layers was distinguished from chitinous procuticle by its position, ultrastructure and sol...