Topic
Angular aperture
About: Angular aperture is a research topic. Over the lifetime, 1771 publications have been published within this topic receiving 27257 citations.
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20 Jul 2005TL;DR: In this article, an electron beam applying apparatus includes an electrostatic lens disposed immediately below the electron source and acting as a condensing electrode for condensing the electron beam in a first angular aperture emitted by the source, a condenser lens disposed on a downstream side of the lens and condensing in the crossover point by the lens on the surface of the material.
Abstract: An electron beam applying apparatus includes: a thermal field emission type electron source emitting an electron beam; an electrostatic lens disposed immediately below the electron source and acting as a condensing electrode for condensing the electron beam in a first angular aperture emitted by the electron source in a second angular aperture smaller than the first angular aperture; a condenser lens disposed on a downstream side of the electrostatic lens and condensing the electron beam condensed in the second aperture angel by the electrostatic lens in a crossover point; and an objective lens disposed on a downstream side of the condenser lens and condensing the electron beam condensed in the crossover point by the condenser lens on the surface of the material.
9 citations
TL;DR: A CdS acousto-optic tunable filter has been constructed and operated near the band gap and exhibits a large enhancement of spectral resolution that is due to birefringence dispersions.
Abstract: A CdS acousto-optic tunable filter has been constructed and operated near the band gap. The filter exhibits a large enhancement of spectral resolution that is due to birefringence dispersions. Over the wavelength range 530 to 545 nm, a half-power bandwidth of 20 A was obtained with an angular aperture of 38 degrees.
9 citations
18 Jun 1992
TL;DR: In this article, a hemispherical lens antenna was developed for the reception of direct to home satellite broadcasts in Europe, which uses a homogeneous lens and flat reflector to give an angle of scan of +or-60 degrees without degradation in performance.
Abstract: A hemispherical lens antenna has been developed for the reception of direct to home satellite broadcasts in Europe. The antenna uses a homogeneous lens and flat reflector to give an angle of scan of +or-60 degrees without degradation in performance. Artificial dielectric material consisting of spherical voids in polystyrene is used to realize the necessary lens dielectric constant. Unlike previous implementations of the hemispherical lens approach, the reflector is extended beyond the surface of the lens to maintain the effective aperture area of the antenna with scan angle. >
9 citations
05 Jul 2008
TL;DR: In this paper, the authors examined the convergence of the transmitted power of an electrically small aperture to the transmission cross section 3 lambda 2/4pi of it for a case of a circular aperture with a ridge.
Abstract: In this paper, we have examined the convergence of the transmitted power of an electrically small aperture to the transmission cross section 3lambda2/4pi of it for a case of a circular aperture with a ridge. This property can be applied for any electrically small aperture regardless of size or shape even though only one example of the circular aperture is shown. Although not shown here, the comparison of the field distributions on the aperture with and without the ridge shows that the aperture fields for the original circular aperture is mainly reactive, while those are radiating for the ridged aperture.
9 citations