We propose and numerically analyze a plasmonic Bragg reflector formed in a graphene waveguide. The results show that the graphene plasmonic Bragg reflector can produce a broadband stopband that can be tuned over a wide wavelength range by a small change in the Fermi energy level of graphene. By introducing a defect into the Bragg reflector, we can achieve a Fabry-Perot-like microcavity with a q...

Abstract The reflector on an impulse radiating antennas (IRAs) is normally designed to be paraboloidal in shape, and are oriented so that the electrical feed point of the TEM feed line coincides with the focal point of the paraboloid. In many practical cases, the feed point and focal points are not exactly aligned, producing some defocus of the reflector. There are two types of defocus that can...

Free space optics is considered the topic of the day and have a large variety of applications which free space separates source from destination such as External cavity tunable laser (ECTL). In ECTL, laser source emits Gaussian beam that propagates in plane with substrate until reach external reflector. The efficiency of these applications depends on the amount of light that coupled back to the...

We report the experimental demonstration of a new design for external cavity hybrid lasers consisting of a III-V semiconductor optical amplifier (SOA) with fiber reflector and a photonic crystal (PhC)-based resonant reflector on SOI. The silicon reflector is composed of an SU8 polymer bus waveguide vertically coupled to a PhC cavity and provides a wavelength-selective optical feedback to the la...

Abstract. Reflector antennas are characterized by very high gains (30 dB and higher) and narrow main beams. They are widely used in satellite and line-of-sight microwave communications as well as in radar. Reflector antennas operate on principles known long ago from the theory of geometrical optics. The first reflector system was made by Hertz back in 1888 (a cylindrical reflector fed by a dipo...

─ This paper presents and evaluates a parallel time domain analysis of a rectangular reflector on multicores machine. Rectangular reflector antennas have motivated the time-domain analysis of electromagnetic scattering problems. The asymptotic time domain physical-optics (TDPO) is applied to the analysis of a rectangular reflector illuminated by a Gaussian-impulse. It is a numerical technique u...

This paper reports a study identifying the learning styles preference of undergraduate nursing students and examining its influence on educational outcomes. There are limited recent studies in the UK on the learning styles preference of undergraduate and its influence on educational outcomes. A purposive sample of 110 undergraduate nursing students completed a demographic questionnaire and the ...

The future National Polar-orbiting Environmental Satellite System (NPOESS) Microwave Imager/Sounder (MIS), a space-borne conical scanning radiometer, uses an offset main reflector with multiple antenna feedhorns to receive upwelling microwave radiation from the Earth’s surface and atmosphere. The offset reflector approach is a convenient and economic way to achieve the desired antenna footprint...

NURBS surface representation, combined with Differential Evolution (DE), enables us to perform automated non-imaging reflector design. The overall result is a simple automated nonimaging reflector design technique and only a little data such as desired illuminance distribution and searching limits are needed. Merit functions specific to non-imaging reflector design are presented. Using differen...

A novel input coupler that can operate in two different frequency bands separately is proposed this paper. The dual-band (X/Ku) signals are by rectangular waveguides, respectively, particular, a Bragg reflector inserted one of the waveguides to avoid electromagnetic backflow, and then circular TE01/TE02 modes excited cylindrical cavity field diffraction through coupling holes with help coaxial ...