Parabolic reflector

About: Parabolic reflector is a research topic. Over the lifetime, 3375 publications have been published within this topic receiving 30735 citations. The topic is also known as: paraboloid reflector & paraboloidal reflector.

Low-cost thin-film concentrator solar cells

Abstract: A low cost concentrating photovoltaic system includes a condenser system having refractive or reflective optics and a photovoltaic module having one or more thin film solar cells. The thin film solar cells may be a-Si, CdTe, Cu(InGa)Se 2 , organic solar cell or dye sensitized solar cells. The condenser system may be a flat, cylindrical or hemispherical Fresnel lens, a parabolic reflector, a compound parabolic concentrator, a reflective V-trough, or a combination thereof. The condenser system has a concentration ratio of about 10 to 100 or higher. No tracking system is needed in many examples, or a simple one-axis tracking may be used. In one example, the condenser system uses a hemispherical Fresnel lens which focuses sunlight onto a hemispherical focal surface, and one thin film solar cell (mounted on a tracking unit) or multiple cells (without tracking) are disposed on the hemispherical focal surface of the Fresnel lens.

Optical device for wide waveband plane grating dispersion type imaging spectrometer

Abstract: The invention provides an optical device for a wide waveband plane grating dispersion type imaging spectrometer, and relates to the technical field of imaging spectrometers in the earth observation field. The optical device solves the defects of the conventional plane grating spectrometer that only the aberration of center wavelength is corrected, the residual aberration is larger, and large astigmatism exists along the length direction of a slit. The optical device consists of an aperture diaphragm, an off-axis parabolic mirror, an entrance slit, a spherical collimating mirror, a plane grating, a plane mirror, a toroidal focusing mirror and a planar array focal plane detector. The entrance slit is positioned on a focal plane of a front optical system; the front optical system consists of the aperture diaphragm and the off-axis parabolic mirror; the emergent light passing though the entrance slit is projected onto the spherical collimating mirror and is then projected onto the plane grating after being collimated by the spherical collimating mirror; and the diffraction light emerged from the plane grating is projected onto the toroidal focusing mirror after being reflected by the plane mirror and then is focused and imaged by the toroidal focusing mirror onto the planar array focal plane detector. The optical device is particularly suitable for a hyperspectral imaging system in the aerospace remote sensing earth observation field.

Equipment for detecting buried non metallic objects - uses cross correlation technique on echoes from loudspeaker at focus of parabolic reflector

Abstract: The apparatus detects inhomogeneities using echo and cross correlation technique. A loudspeaker is mounted above a microphone at the focal point of a parabolic reflector. A number of microphones and loudspeakers may be mounted in a row in a single elongated reflector, or the reflector may be of rectangular section with a resonating membrane across its face. The signal processing network produces a timed pulse modulated signal from the loudspeaker. The timing circuit gates out the directly received pulse from the detection networks which include a logarithmic amplifier. It applies a cross correlation algorithm to the transmitted and reflected signals to display any results on a display unit.

Electronically controlled array for simulation of passive target/background signatures at millimeter wavelengths

Abstract: A system for an electronically controlled array for the simulation of passive signatures and noise at millimeter wavelengths. The system can simulate passive background signatures and also superimpose radiation intensity variation to simulate either moving or stationary passive signatures of targets over or within the background. A single, non-varying source of millimeter waves provides the non-coherent radiation for illumination that is required for simulating passive signatures. A controlled array variably controls radiation intensity at each illumination point of the array. The non-varying source is concentrated at the focal axis of a parabolic reflector, providing a plane wavefront of radiated energy.

A X-Band Planar Transmit-Array

Abstract: Planar arrays are a very interesting option to substitute reflector antennas because of their well-known characteristics of low profile, potential low cost, reliability and flexibility in achieving contoured beams and multiple beams with a simple planar geometry. Suitable solutions using planar antennas for space applications have been proposed using reflect-arrays with countered beams and multibeam. Another proposed solution consists of transmit arrays. In this case, the antenna acts as a lens [1]. This consists of a periodic planar array having two patch antennas connected by a line. One element receives the signal from –z direction and the other transmits the signal in the +z direction. By a proper selection of the phase delay in the connection line, the phase distribution in the transmitting array can be adjusted. In an equal output phase configuration the transmitting array behaviour would be similar to the obtained with a parabolic reflector, having the advantage of removing the feed blockage.