Abstract: A multi-octave thick dielectric radome wall which includes a dielectric slab having a pair of surfaces and a plurality of pyramidal-shaped dielectric elements mounted on at least one of the surfaces of the dielectric slab. The dielectric constant of the elements is typically greater than the dielectric constant of the slab. In an alternate embodiment, a second dielectric slab is provided adjacent to one of the first dielectric slab surfaces having the elements mounted thereupon with support means for supporting the second dielectric slab in a spaced apart relationship with the first dielectric slab.

Abstract: An antenna reflector having a parabolically curved reflecting surface is formed of a cellular ceramic material having ceramic fibers fused together in a rigid cellular structure. The body is formed by bonding or fusing a mass of silicon dioxide fibers together at their points of intersection with a fusing agent such as boron nitride in a sintering process, resulting in a fused array of fibers with cellular porosity intentionally distributed through the body to reduce its density. Other types of ceramic fibers can be used either alone or in combination with the silicon dioxide fibers. The antenna reflector finds particular utility in parabolic antennas for satellite microwave communications systems.

Abstract: An electromagnetic lens formed of a refractive material with a reflective rface. The lens is a body of revolution having an upper parabolic reflective surface and spherical side and bottom surfaces. Incoming radiation is refracted at one spherical surface, reflects from the reflective surface, exits and is refracted at the other spherical surface. The radiation may be directed onto an array of electromagnetic detectors. Such an array may consist of concentric circles of detectors, such that a particular detector is illuminated by incoming radiation of a particular azimuth and elevation.

Abstract: A radio frequency antenna system is provided comprising: a radio frequency lens having a parallel plate region and having disposed along opposing peripheral portions thereof a plurality of array ports and a plurality of beam ports, such array ports being coupled to an array of antenna elements arranged to provide a plurality of differently, directed relatively narrow collimated beams of radio frequency energy from a common aperture, each one of such beams being associated with a corresponding one of the plurality of beam ports; and, means for coupling radio frequency energy directly into the parallel plate region to provide, from the common aperture, a relatively broad beam of radio frequency energy.In a preferred embodiment of the invention, a plurality of amplifiers is provided, each one of the amplifiers being coupled between an array port and a corresponding one of the antenna elements.

Abstract: An ellipticized singlet azimuth versus elevation optimized and aperture eemized nonspherical acoustic lens antenna of very low or even minimal F-number providing balanced astigmatism for wide angle acoustical applications in underwater sound is described. The acoustic lens has an elliptical periphery and surfaces defined by a system of nonlinear partial differential equations, the surfaces acting together to produce two perfect primary off-axis foci F and F' at a finite distance in back of the lens and two perfect conjugate off-axis foci F.sub..infin. and F'.sub..infin. in front of the acoustic lens at infinity; i.e., the lens simultaneously focuses energy from the primary foci F and F' into two off-axis parallel ray plane wave sonic beams directed towards infinity at equal but opposite angles with respect to the acoustic lens axis.

Abstract: A microwave lens is constructed of a homogeneous body of closed cell rigid polyurethane foam with aluminum flakes dispursed throughout and having a configuration defining an axis and opposed lens surfaces. The method of the invention includes selecting a mold having a cavity of the appropriate configuration, preheating the mold, and filling the mold with a mixture of low density polyurethane foam components and fine aluminum flakes evenly dispersed throughout the foam structure allowing the mixture to cool and form a body of the appropriate configuration.

Abstract: Methods and apparatus for electronically steering a radio frequency signal beam (RF) along at least one of "X" and/or "Y" coordinates with respect to the axis of the signal beam (RF) and comprising n pairs of back-to-back prisms (20, 21) formed of ferroelectric dielectric material such, for example, as BaTiO.sub.3, LiNbO.sub.3, LiTaO.sub.3, Bi.sub.12 SiO.sub.20 (BSO) and Bi.sub.12 GeO.sub.

Abstract: A number of planar diplexers which intersect a beam radiated from a primary projector at respectively predetermined angles, which are separated from the projector and from each other, are provided with respectively predetermined conductor patterns. The diplexers are arranged successively in a frame together with the primary projector, whereby various radiation patterns can be formed by different combinations of a number of beams which are reflected respectively by the planar diplexers at respectively predetermined rates. As a result, a power distribution type antenna having a small and simple structure adapted for multipurpose and multifunction applications, particularly for installation on a communication satellite, based on the portability and the ease of assembling thereof, can be realized.

Abstract: A dome antenna including a dome of solid dielectric material and scannable feed array positioned in the base plane thereof. The dielectric material of the dome constructed to provide a dielectric constant that varies with the perpendicular distance from the base plane. Rays emanating from the base plane are continuously refracted within the dome and refracted at the surface thereof, the interface with free space, to accomplish sufficient a scan angle amplification for scanning beam to the horizon and below.

Abstract: A lightweight mixed dielectric and a manufacturing method thereof is described, which is prepared by mixing metal-coated expanded particles of plastic, glass or silica, thin-wall metal pipes or metal coated thin-wall plastic pipes and uncoated expanded particles of plastic, glass or silica and then forming the resulting mixture into a desired shape by thermal expansion or by the use of binder with the provision that these uncoated expanded particles are only made of plastic when the forming step is carried out by thermal expansion.

Abstract: An ellipticized singlet azimuth versus elevation optimized and aperture eemized nonspherical lens antenna of very low or even minimal F-number providing balanced astigmatism for wide angle acoustic, microwave or optical applications is described. The lens has an elliptical periphery and surfaces defined by a system of nonlinear partial differential equations, the surfaces acting together to produce two perfect primary off-axis foci F and F' at a finite distance in back of the lens and two perfect conjugate off-axis foci F.sub..infin. and F'.sub..infin. in front of the lens at infinity; i.e., the lens simultaneously focuses energy from the primary foci F and F' into two off-axis parallel ray plane wave beams directed towards infinity at equal but opposite angles with respect to the lens axis. The lens may be built of various materials depending on its intended application in acoustics, microwaves or optics.

Abstract: Various aspects of electro-magnetic testing are facilitated by inserting a foamed plastic dielectric lens at a particular position between a particular radiating source and the test aperture. The lens is constructed according to electro-optic formulae and the radiation wavelength to produce a plane wave of uniform phase. To control extraneous energy contributed by reflections from the flat face of the lens, this surface is provided with two layers of high-performance absorber material. The amplitude characteristics in the test region are controlled by appropriate selection of the source antenna. Radiation-absorbent material is also provided to eliminate amplitude distortion. This makes possible testing under far-field conditions in test cells of modest size, which has heretofore been possible only with elaborate parabolic reflectors. Weather restrictions on use of free-space ranges, the sheer size of such ranges, and security problems attendant on their use, are all thus avoided.

Abstract: A low reflectivity radome includes an enclosure wall made of foamed plastic material defining a dielectric constant of about 1.08. Stiffening ribs made from reinforced glass fibers with a dielectric constant of about 4.0 are arranged in an orthogonal manner along planes normal to a tangent to the air-side surface of the radome and at least partially embedded in the enclosure wall for compressive strengthening thereof. Different orthogonal arrangements include the ribs being totally embedded within the enclosure wall, the ribs projecting to uniform or different distances from the inside surface of the enclosure wall or the ribs are arranged in closely, spaced-apart pairs and project from the inside surface of the enclosure wall. When the ribs are totally embedded in the formed plastic material, the distance between the ends of the ribs and each face surface of the enclosure is selected so that incident microwaves undergo identical phase shifts for all parallel paths through the enclosure wall.

Abstract: A plurality of dielectric plates are disposed side by side to form a dielectric plate assembly and matching layers are respectively disposed adjacent to both end faces of the dielectric plates. A plane wave is incident on one of the matching layers perpendicularly thereto and passes through the dielectric plate assembly and are emitted from the other matching layer. Ratios b/a and a/.lambda..sub.0 (a being the distance between the centers of adjacent ones of the dielectric plates, b the thickness of each dielectric plate and .lambda..sub.0 the free space wave length of the electric wave) are selected so that the frequency characteristics of the phase difference between the electric field components of the plane wave respectively perpendicular and parallel to the dielectric plates, which are produced by the passage of the plane wave through the dielectric plate assembly, has a value of 90.degree. at two different values of a/.lambda..sub.0.

Abstract: A radio frequency antenna having a microstrip feed network and a flared radiating structure directly fed by such microstrip feed network. A wedge-shaped dielectric structure is disposed in the narrow region of the flared radiating structure to match the impedance of the antenna to the impedance of free space. An E-plane array antenna includes a plurality of antenna elements, each including a single feed element on a dielectric board. An H-plane array antenna includes a plurality of feed elements on a single dielectric board. A cover, having an absorbing material, is disposed over the microstrip feed network to suppress stray radiation from propagating from such feed network.

Abstract: A wavefront flattener comprising an input surface, an output surface paral to said input surface, said input surface and said output surface comprising concentric rings of dielectric material, said concentric rings having a high dielectric constant at the center thereof dropping to a low dielectric constant at the outermost rings whereby electromagnetic radiation is crowded into the center of said input and output surfaces to cause a flattening of a curved electromagnetic radiation wavefront.