نتایج جستجو برای: reflector
تعداد نتایج: 4298 فیلتر نتایج به سال:
The suitability of various radiating systems for generating a directive high power microwave (HPhl ) beam is investigated. It is concluded that offset reflector antenna systems are well suited for this purpose. An HPM reflector antenna may consist of one or two reflectors that are illuminated by single or array feeds. To accurately predict the performance of an HPM reflector antenna, a versatil...
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...
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 relatively fast and simple method utilizing Gaussian beams (GBs) is developed which requires only a few seconds on a workstation to compute the near/far fields of electrically large reflector antennas when they are illuminated by a feed with a known radiation pattern. This GB technique is fast, because it completely avoids any numerical integration on the large reflector surface which is requ...
1 Introduction The previous researches on the modulated scattering antenna array (MSAA) have shown that the second-order intermodulation scattering signal is relatively low compared with the direct received signal [1]. In this report, a switched reflector is used to solve this problem. The diversity performance of the MSAA with a switched reflector is investigated. It is shown that the diversit...
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...
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