Abstract: A microwave primary source with a phase conical scan having a conical horn containing an obstacle which gives rise to a wave that propagates in the TE.sub.21 mode in quadrature with the TE.sub.11 fundamental mode in the opening of the horn; the obstacle is driven in rotation round the axis V of the horn.

Abstract: A device for separating signals in the long or radar wavelength bands from signals in the short or infrared to ultraviolet wavelength bands which occupy a common area. A waveguide for directing radar band wavelengths has apertures in opposing walls of the waveguide, a first of which is rectangular and has a greater length and width than the broadwall dimesnion of the waveguide; and the other of which is circular with a diameter less than one-half the free space wavelength of the long wavelength signal. A pyramidal feedhorn directs the long signal wavelength through the reactangular aperture, where the short-wavelength signal, which also comes down through the feedhorn passes through the second aperture. The long-wavelength component instead of passing through the second aperture is deflected into the waveguide.

Abstract: A circularly polarizing antenna feed comprises a feed waveguide having a short circuit reflecting plate at one end and a radiating horn at the other, a wave exciter for launching linearly polarized plane waves axially along the feed waveguide in opposite directions, and a grid of parallel reflector strips disposed in a plane which is perpendicular to the waveguide axis and which is located between the wave exciter and the reflecting termination at a distance of approximately .lambda.g/8 from the exciter and approximately .lambda.g/4 from the termination. The reflecting strips of the grid are inclined at an angle of 45.degree. to the direction of polarization of the waves propagated by the exciter, the grid and the reflecting termination together forming a twist reflector which effectively reflects and rotates through 90.degree. the waves incident upon the grid. These reflected waves together with the forwardly propagated waves from the exciter represent circularly polarized waves.

Abstract: A primary radiator for circularly polarized wave in accordance with the present invention is equipped with conductor projections along the inner wall of the horn antenna in order to convert linearly polarized wave to circularly polarized wave within the horn antenna, without adapting the prior art generator of circularly polarized wave. Consequently, it becomes possible to reduce the axial length and the overall size of the radiator. Moreover, the conductor projections are constructed with their edge sections on the aperture end side of the horn antenna sloping down along the inner wall of the horn antenna, so that generation of higher order modes can be suppressed and a satisfactory directivity can be obtained.

Abstract: The present invention relates to a multidirectional feed which can be used by itself or preferably incorporated within a surface wave structure to form a flush-mounted antenna on, for example, a mobile unit. The feed arrangement comprises a ground plane including an annular cavity with a smaller annular slot. The annular slot is connected by multiple, spaced-apart, leads to an associated transceiver. The annular cavity is also formed to prevent both a shorting of the radio waves therein and the radio waves from propagating away from the cavity in a direction opposite the slot. A surface wave structure is disposed preferably with the feed centrally mounted and can comprise any suitable structure including annular corrugations and/or a dielectric layer to provide a flush-mounted antenna arrangement which provides radiation in azimuth in all directions with moderate elevation gain.

Abstract: A wide-band microwave antenna capable of radiating over a wide angular field is fed by a rectangular wave guide and includes a first sectoral horn coupled to the rectangular wave guide. The first sectoral horn is sectoral in the H plane. Coupled to the first sectoral horn is a second sectoral horn which is sectoral in the E plane. The second sectoral horn has a partial-cylindrical-shape with circular-shaped outer edges. The second sectoral horn has a top plate and a bottom plate. A plurality of equally spaced power distributors are radially disposed in the second sectoral horn and extend from the top plate to the bottom plate through the entire length of the second sectoral horn. These power distributors thus form a plurality of elementary radiation sources.

Abstract: A microwave lens broadens the radiation pattern of an antenna feedhorn so as to result in improved illumination of the reflector surface. The lens, constructed of dielectric material in the shape of a half-torus, provides feed radiation patterns suitable for use with deep paraboloidal reflectors, typically ones having focal-length-to-diameter ratios between 0.25 and 0.35.

Abstract: A horn antenna construction, particularly for use in microwave radar detector circuits, comprises a molded horn element that is open at its bottom side, with a ridge molded into its flared top surface, and being electrically conductive at least at microwave frequencies such as in the X-band and K-band. The open bottom of the horn element mates to a conductive upper surface on a mounting board, and the horn is drawn down onto the mounting board so that its upper surface forms the bottom of the horn. Thus, the ridge is brought into physical and electrical contact with a feed strip formed in a microstrip board on the mounting board, that has a mixing diode or diodes associated therewith. By this construction, there is a positive and dimensionally stable association of the throat of the horn and the ridge to the feed strip and the mixing diode(s), without the necessity of any solder, inserted connectors or mounting pins, or the provision of any tuning posts or screws.

Abstract: The configuration of a waveguide antenna feed is determined by a shaped body of solid dielectric material which is coated with a conductive material. The conductive material functions as a waveguide wall for constraining electromagnetic wave propagation within the dielectric body. The body includes a mode converter and a coupler to a lead-in structure. A polarization converter, if desired, can be integral with the dielectric body.

Abstract: Multibeam lens antennas are often circular, and utilize propagation in disk-shaped parallel-surface regions. There is phase correction through terms in .theta..sup.2, where .theta. is the angle of an aperture point measured from the boresight direction. In the new designs herein, the lens comprises two portions, each being two closely spaced plates with a dielectric medium between them. One portion is formed as a surface of revolution (cylindrical or conical) with two circular ends, one end being an aperture with element feedpoints coupled to array elements. The other portion is a cap joined to the other end of the first portion. The cap may be a disk or a segment of a sphere. The dimensions and indices of refraction are selected to provide focus points for feed ports, with each focus being for a specific beam direction. The parameters may be selected so that the focus points are within the cap, at the periphery of the cap, or at the aperture. Some of the new designs have phase correction through .theta..sup.

Abstract: The wide ends of two similar horn structures are juxtaposed and joined by a rotary bearing extending thereabout which permits relative rotational motion between the two horn structures. A field shaping lens may be disposed at the relatively rotatable horn juncture to help insure substantially planar wavefront shapes across the relatively rotatable joint. An annular aperture may also be provided between the relatively rotatable horns and electrically loaded so as to present an approximate short circuit electrical impedance at the intended frequency of operation.

Abstract: A mode converter is disclosed which selectively generates a predetermined higher order mode(s) from an incident fundamental mode. This mode converter comprises a dielectric region having an effective-dielectric-constant/thickness profile which is the same as the amplitude profile of the desired higher order mode(s).

Abstract: The present invention relates to hybrid mode feeds which are capable of handling very wide bandwidths. In the present feed arrangements, a dominant TE.sub.11 mode is converted to the HE.sub.11 hybrid mode which is then launched. The TE.sub.11 to HE.sub.11 mode conversion is achieved by inserting a circular dielectric rod (12) into a flared end (11) of a smooth-walled cylindrical feedhorn until a small cylindrical section of the dielectric rod engages with the inner wall (15) of the unflared portion of the feedhorn. In one feed arrangement, the other end of the dielectric rod is similarly inserted into a flared end (21) of a corrugated cylindrical feedhorn section (22) until a short longitudinal section of the cylindrical portion of the rod is concentric with the corrugations of an unflared section of the feedhorn to provide a transition for the HE.sub.11 mode into the corrugated waveguide for subsequent launch.

Abstract: An H-plane sectoral horn antenna is loaded with low-loss dielectric inserts n alternative embodiments so as to reduce beamwidth, increase axial gain and to achieve non-mechanical beam scanning. In one embodiment, the antenna is transversely loaded with a multi-layer dielectric array containing an air gap of critical thickness between four dielectric strips. In another embodiment, the antenna is longitudinally and symmetrically loaded with wedge-shaped dielectric strips separated by a critical air gap between the dielectric and antenna walls.

Abstract: A radar detector adapted to be carried by a motor vehicle, includes a housing enclosing a compact horn antenna having a tapering wall portion which defines a cavity extending from an aligned aperture within the housing. A plano-convex dielectric lens extends across the aperture and cavity and introduces a microwave phase delay decreasing from the center of the cavity towards the tapered wall portion of the horn antenna to compensate for the deficiencies in the compromised design of the antenna and for significantly increasing the sensitivity and gain of the detector. The dielectric lens may project outwardly from the housing or inwardly into the antenna cavity and may be molded as an integral part of the front wall of the detector housing. In one embodiment, the lens is also adapted to be conveniently attached to an existing radar detector.

Abstract: Apparatus for the generation and radiation of microwave radiation including a microwave oscillator having a cavity resonator directly coupled with the input of a horn resonator by way of a first apertured diaphragm. There is arranged within the horn radiator a second apertured diaphragm disposed at a distance from the first apertured diaphragm such that together with the first diaphragm it forms a filter resonator.

Abstract: An antenna of the discone type is omnidirectional in bearing and has a diagram whose directivity in elevation can be adjusted. At the apex end of each cone a dielectric disc of predetermined thickness is inserted parallel to the base of the cone concerned. In the central portion of the antenna these two discs create conditions for the propagation of energy which are different from those existing outside the discs, the result being an improvement in the phase pattern in the radiating aperture of the antenna.

Abstract: A conical horn antenna is disclosed having dual dielectric bands mounted therein for improving the rotational symmetry or elipticity of the radiated beam as well as the efficiency. The first and second dielectric bands are coaxially mounted to each other and to the conical horn. The lengths of the bands are determined by the frequencies being propagated. A circularly polarized dominant wave such as TE.sub.11 mode is applied to the antenna and excites a series of higher order waves such as the TM.sub.11 mode. The circularly polarized dominant and the higher order modes are propagated toward the aperture where they are in phase and therefore add vectorially. The dual dielectric band acts as a slow wave structure and higher order waves which in turn provide an improved phasing between the dominant modes.

Abstract: The rear wall of a horn antenna is a substrate with a phase shifter circuit thereon. Power from the phase shifter is radiated by the horn via a probe that has the general shape of a hook.

Abstract: A multisided horn antenna such as a square horn is disclosed having an improved axial ratio circular polarization or ellipticity. Ellipticity of a square horn antenna is improved by placing a conical section or ring of conductive material at the aperture of a horn antenna. The conical ring causes a relatively directive beam having a low axial ratio to be produced throughout most of the pattern generated similar to that of a conical horn antenna. Yet, the square horn antenna provides increased power over a conical horn.

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 horn for radiating circularly polarized energy includes a rear launcher section commencing with a double-ridged cross section and ending at the horn flare with a square cross section with the plane of polarization so that the wave excited in the square cross section is along a diagonal of the square. The horn flare section opens up to a dimension of approximately 70% larger than the square throat dimension to narrow the elevation beam. A dielectric slab oriented in the horizontal plane is seated in the flare section for introducing a frequency-varying differential phase shift between orthogonal modes for effectively compensating for the inherent phase shift in the flare. Refracting lenses that are half-cylinders having a diameter of about 25% of the horizontal aperture dimension with their axes aligned vertically are located close to the vertical aperture edges for refracting the energy at the horn edges into the region between 30.degree. and 60.degree. from the horn axis.

Abstract: An antenna element is disclosed having a printed circuit parallel plate region with a parabolically shaped reflecting wall and a flared radiating section. The flared radiating section is disposed along an aperture which intersects the axis of the parabola at an acute angle. A microstrip feed formed integrally with the printed circuit parallel plate region is offset from the reflecting wall and is adapted to introduce radio frequency energy at the focal point of such reflecting wall. Load material is disposed adjacent to the focal point to absorb radio frequency energy reflected by the aperture thereby improving the VSWR of the feed. Such arrangement enables close element-to-element spacing in an array, thereby substantially eliminating grating lobes while enabling intermeshing of the elements to provide port and starboard array antennas.

Abstract: A cylindrically shaped leaky wave antenna utilizing a cylindrically shaped printed grid antenna fed by a curved wave guide feed array utilizing anti-phase edge cut slots cut in accordance with a phase synthesis technique to provide a desired squinted beam resulting in a low cost conformal antenna without the use of active phase elements.

Abstract: A dielectric lens for a flared microwave horn, the lens correcting the phase error introduced in microwaves passing through the horn. The lens comprises a plurality of parallel dielectric discs disposed concentrically with the horn in the path of microwaves passing through the horn. The disc have different diameters so that different portions of the microwaves pass through different numbers of the discs to compensate for the phase error introduced by the flared horn. The impedance discontinuities of the discs are matched out by appropriate spacing of the discs. The discs are preferably flat sheets of dielectric material so that they are easy to fabricate, and they are preferably supported by a central axial support means to minimize interference with microwaves passing through the discs. The number, thickness and diameters of the discs may be selected to produce substantially zero phase error in any given flared horn.