Other

Solar Energy Technology, Inc.

United States of America As Represented by the Secretary of the Air Force

Carlyle J Sletten

Sheldon B Herskovitz

F Sheppard Holt

E J Sletten

Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60.degree. in elevation angle by 120.degree. or more in the azimuth sectors with a collector concentration ratio of approximately 3.0. Miniaturized construction of the circular dielectric rods with internal absorbers reduces the weight per area of glass, plastic and metal used in the collector panels. No external parts or insulation are needed as heat losses are low due to partial vacuum or low conductivity gas surrounding heated portions of the collector. The miniature internal absorbers are generally made of solid copper with black selective surface and the collected solar heat is extracted at the collector ends by thermal conductivity along the absorber rods. Heat is removed from end fittings by use of liquid circulants. Several alternate constructions are provided for simplifying collector panel fabrication and for preventing the thermal expansion and contraction of the heated absorber or circulant tubes from damaging vacuum seals. In a modified version of the internal absorber collector, oil with temperature dependent viscosity is pumped through a segmented absorber which is now composed of closely spaced insulated metal tubes. In this way the circulant is automatically diverted through heated portions of the absorber giving higher collector concentration ratios than theoretically possible for an unsegmented absorber.

Internal absorber solar collector

A reflector antenna system is described suitable for ground stations used in communication with geostationary satellites. Dual beams or multi-beams can be directed at several satellites spaced angularly from 5.degree. to 20.degree. apart and these beams are scanned by feed motion keeping a single main reflector surface fixed. Offset feed geometry is used for low aperture blocking and shaping of subreflectors and main reflector results in very high aperture efficiencies, low sidelobes and symmetric low cross-polarization patterns needed for satellite links. A novel method for shaping subreflectors using the ratios of ray lengths squared and variable focal lengths is applied in the optimally tilted offset geometry results in almost uniform aperture power distributions. A new general procedure for shaping doubly curved surfaces intercepting a known population of rays such that these rays are focused to a point or reflected in a given direction is used to shape the main reflector for elimination of aperture phase errors and to shape a second subreflector which focuses perfectly to the apex of a second feed horn.

Offset-fed multi-beam tracking antenna system utilizing especially

A solar energy concentrator comprising a cylindrical Fresnel lens, a specially shaped and positioned reflecting mirror, and a shaped tubular receptor for conveying the collected energy to terminals is described. These concentrators are arrayed parallel and contiguous to each other and oriented generally along an East-West line to receive the sun's radiant energy, and the lenses together with the special reflectors and designed to accomodate large elevation angle variations of the sun. The large acceptance angles achieved with the image collapsing concentrator, while at the same time maintaining a high concentration ratio, improves the reception of diffused as well as direct sunlight and the small surface area of receiving tubes diminishes the thermal radiation losses. A method for determining the shape and location of the special image collapsing reflector is described and applied to solar concentrators employing both lenses and reflectors of cylindrical and three dimensional forms.

Image collapsing concentrator and method for collecting and utilizing

A compact, all channel television antenna system is provided for improved reception within buildings where multiple reflections or ghosting and weak signals are typical operating conditions. The high performance in this environment with a very small antenna is achieved by the antenna's directive gain and pattern nulls, good impedance matching, low acceptance of vertical polarization, band switching, and repeatable orientation of the antenna. The antenna is characterized by a miniature, symmetrically top-loaded dipole and efficient matching circuit at the lower VHF television band. The top-loading elements are reused as parasitic elements in a compact, directive array at the upper VHF channels. Similarly, in the UHF television bands bending and top loading is used to reduce the size of radiators and to provide loading for the VHF bands. A construction of UHF half loops in parallel is used with a system of reflecting and directing elements.

Compact, directive, broadband antenna system having end loaded dipoles

A portable multiband H.F. antenna that has minimum ground area requirements and that is capable of transmitting electromagnetic wave radiation with horizontal polarization, azimuth plane omnidirectional patterns and a null in the vertical beam pattern is realized by means of an easily erectable tower type radiator. The tower structure has adjacent conductive leg members that define an elongated antenna slot aperture the total length of which is resonant to the lowest operating frequency band. A microwave transmission line resides along one side of the slot and the slot aperture is fed by shorting the transmission line to the oposite side of the slot. Operation at higher frequency bands is achieved by shorting out sections of the slot aperture on both sides of the feed. An array of radiating slot apertures can be provided by shorting the full slot aperture into sections and feeding each slot section separately. The addition of capacitance to the feed circuit permits operation at frequency bands below that provided for by the full slot aperture length.

Growing community of inventors

Acton, MA, United States of America

Carlyle J Sletten