Abstract: In one embodiment, an electromagnetic (EM) energy containment device includes a spherically symmetric resonant dielectric structure having a radial dimension R0 defined as R0=3/?·?0/2 and having first and second regions with different indices of refraction. The spherically symmetric resonant dielectric structure is configured to receive and to contain, for a selectable duration of time, an electromagnetic wave of a wavelength ?0, and can find applications in delay circuits for beam steering for example.

Abstract: A radiator (A) has a receiver segment (22) and an adjacent transformer segment (24). The receiver (22) has a first (26) and an opposite second face (28). The second face (28) includes a generator (30) of a signal (20) that propagates from the receiver segment (22). A first face (32) of the transformer segment (24) is formed adjacent to the receiver segment second face (28). A transmitted signal (20) propagates through the transformer segment (24) from the first (32) to a second face (34). A plurality of free floating plates (38) are formed within the transformer segment (24) in layers (40) with gaps (42) permitting signal (20) passage. The floating plates (38) deflect the signal path through the transformer segment (24).

Abstract: The present invention provides a radome for an endfire antenna array that includes a honeycomb core, an inner skin attached to the honeycomb core, a first set of conductive slats disposed on the inner skin of the honeycomb core and a second set of conductive slats that are disposed within the honeycomb core. The two sets of conductive slats are capacitively-coupled to one another.

Abstract: The present invention provides a radome for an endfire antenna array that includes a honeycomb core, an inner skin attached to the honeycomb core, a first set of conductive slats disposed on the inner skin of the honeycomb core and a second set of conductive slats that are disposed within the honeycomb core. The two sets of conductive slats are capacitively-coupled to one another.

Abstract: A horizontally polarized end fire antenna array providing 360° scanning over a ground plane including a plurality of radiating cavity backed slots formed by a plurality of mutually separated flat, segments of metallization arranged in a grid and supported by a layer of dielectric material in a coplanar arrangement above and shorted to the ground plane. The side edges of the metallic segments define a plurality of substantially linear crossed slots running in at least two, e.g. orthogonal, directions. Each element of the array consists of four or more adjacent metallized segments having mutually opposing inner corners surrounding a common feed point. RF launch points for the array are formed across the slots of pairs of neighboring segments by conductor elements connected to respective common feed points.

Abstract: A horizontally polarized end fire antenna array providing 360° scanning over a ground plane including a plurality of radiating cavity backed slots formed by a plurality of mutually separated flat, segments of metallization arranged in a grid and supported by a layer of dielectric material in a coplanar arrangement above and shorted to the ground plane. The side edges of the metallic segments define a plurality of substantially linear crossed slots running in at least two, e.g. orthogonal, directions. Each element of the array consists of four or more adjacent metallized segments having mutually opposing inner corners surrounding a common feed point. RF launch points for the array are formed across the slots of pairs of neighboring segments by conductor elements connected to respective common feed points.

Abstract: An array of dual trough radiator elements including orthogonally crossed trough waveguide cavities and RF feed members of predetermined adjustable length extending across the cavities from one radiator element to its neighbor, where the feed members are suspended in a slot formed in the body radiator elements and where the inner or proximal ends are connectable to an RF energy source while the outer or distal end is unconnected in an open circuit arrangement. The array also includes intermediate support members of electrical insulation located on an outer surface of the radiator element and a switchable parasitic ground plane consisting of a set of parasitic conductor elements is located on a top surface of the intermediate support member.

Abstract: An array of dual trough radiator elements including orthogonally crossed trough waveguide cavities and RF feed members of predetermined adjustable length extending across the cavities from one radiator element to its neighbor, where the feed members are suspended in a slot formed in the body radiator elements and where the inner or proximal ends are connectable to an RF energy source while the outer or distal end is unconnected in an open circuit arrangement. The array also includes intermediate support members of electrical insulation located on an outer surface of the radiator element and a switchable parasitic ground plane consisting of a set of parasitic conductor elements is located on a top surface of the intermediate support member.

Abstract: Apparatus which overcomes the blockage effect of an object in the path of a beam of RF energy, includes a conformal array of parasitic electrical conductor elements having a length of about .lambda./3 and which are selectively located above the surface of the object, also at a height of about .lambda./3. The parasitic conductor elements operate to duct the RF energy of the beam around the object with minimal loss in gain and effect on the beam's radiation pattern.

Abstract: A radar antenna system, adapted to be supported on an aircraft for surveillance, employs a nonconducting disk radome structured with aerodynamic fairing and otherwise to produce relatively low aerodynamic drag. A plurality of struts are used to secure the disk radome to the aircraft with the disk radome generally extending in a solid horizontal reference plane. A plurality of elongated, relatively low gain radiating elements are supported by a ground-plane box within the disk radome, with the radiating elements distributed across the disk radome and disposed to radiate generally in the vertical direction. An electronic system is supported within the ground-plane box, and it includes respective transmit/receive circuits which send and receive radio frequency signals to and from the radiating elements. Power cables extend through the struts to couple signals between the electronic system in the disk radome and radar system level circuitry located externally of the disk radome.

Abstract: A full coverage antenna module provides radiation in 360.degree. in a weight, space and cost effective manner. The antenna module includes two back-to-back electronically scanned (.+-.60.degree.) antenna arrays and an end-fire array mounted on at least one of a top surface and a bottom surface of the module. The end-fire array is bi-directional, may be scanned by .+-.30.degree. in both of its directions, and serves as a gap filler to provide coverage not supplied by the side arrays. The end-fire array may include a plurality of rows of antenna elements, adjacent rows of which are separated by an offset width. Preferably, the antenna elements in the rows have a non-periodic inter-element spacing. The antenna elements in the end-fire array may be of different types, for example, both monopoles and dipoles may be used in the same end-fire array. If monopoles are used, they are preferably mounted on a corrugated ground plane.

Abstract: A tilted helical element antenna array has increased effective aperture. By tilting individual helical radiators relative to one another, the region of aperture overlap may be decreased to thereby increase the effective aperture of the array. Helical radiators are disposed at a radiator spacing which is less than the operating wavelength .lambda.. At such a small spacing, the apertures of each of the helical radiators overlap. To decrease this aperture overlap region and thereby increase the effective aperture of the array, each of the helical radiators are tilted relative to one another. Thus, a compact antenna having an increased effective aperture is provided.

Abstract: An efficiently radiating helical antenna includes a conductive helix receiving signals to be radiated at a first end of the conductive helix device for capacitively pulling fields generated by the signals towards a second end of the conductive helix opposite the first end. The device may be a conductive tube inserted into the second end of the conductive helix or a disjointed conductive helix surrounding the conductive helix. This scheme works especially well for a conductive helix having a circumference on the order of one wavelength.

Abstract: A nonsquinting end-fed quadrifilar helical antenna is provided. Each conductor of the antenna is fed with a successively delayed phase representation of the input signal to optimize transmission characteristics. Each of the conductors is separated into a number Z of discrete conductor portions by Z-1 capacitive discontinuities. The addition of the capacitive discontinuities results in the formation of an antenna array. The end result of the antenna array is a quadrifilar helical antenna which is nonsquinting (radiates in a given direction independently of frequency).

Abstract: A non-squinting helical antenna is divided into segments separated by a coupler. This coupler is preferably a four port coupler which serves as a summation and difference power divider. Such a four port coupler allows the formation of a closed loop for controlling the steering angle of the antenna. The summation and difference signals between segments are monitored, and the ratio of these signals is used to determine and correct error in steering. The steering angle of the antenna can thus be maintained over a range of frequencies within a decibel of error.

Abstract: A quadrifilar helical antenna including four conductive helices having a common central axis, a common direction of turn about said axis, a common pitch, and a common length between opposite ends, the helices being uniformly spaced from each other by 90.degree., and a single dielectric helix concentric with the common axis, lying within and supporting the conductive helices at a nominal diameter. The dielectric helix has opposite ends, a plurality of turns having said common direction of turn, and a second pitch substantially greater than said common pitch. A casing contains the helices and is rotatably fixed to one end of the dielectric helix. A tuning device is fixed to the other end of the dielectric helix and rotatable relative to said casing, so that rotation of the tuning device twists the dielectric helix to alter the common pitch of the conductive helices without substantial variation from said nominal diameter.

Abstract: An antenna element for radiating electromagnetic signals having a first and a second generally C-shaped groundplane that are formed of conductive material. The groundplanes are connected to one another and define a notch which has one end that is open to free space. An elongated section of transmission line is disposed between the two groundplanes. The transmission line has a source receiving end connectable to a signal source and also has a feed end opposite to the source receiving end. A segment which acts as a transformer is located within the notch. The transformer segment has a first end that is connectable to the feed end of the transmission line and has a second end which faces the notch open end.Preferably, at least one transformer step is located along the transmission line between the source receiving end and the feed end. Also, an open circuit section of transmission line is preferably connected to the transformer segment second end.

Abstract: A microwave buffer for use between transmitter modules and an impedance combiner. The buffer is comprised of a plurality of input segments, a plurality of output segments and an elongated transmission segment connecting the input segments to the output segments. The geometry of the buffer along with bridges located proximate to the transmitter modules eliminate the destructive effects of reflected waves set up by an unbalanced impedance combiner when one of the transmission modules becomes inoperative. The hourglass shape of the buffer causes the phases of the signals from each transmission module to be equal from any transmission port to any output. The bridges force the sum of the mutual couplings to be low in amplitude on any transmission module.

Abstract: A negative slope phase skewer for use between radiating elements of series fed antenna array. The phase skewer has a four part coupler having two segments lying parallel to one another, each segment being a near and a far branch. The two near branches connect to the transmission line, while the far branches are at some distance from the transmission line. A series of spaced apart, progressively longer, high impedance open circuited stubs extends outward perpendicularly from each far branch. Two conductive connections connect the two segments between the transmission line and the stubs. Each stub is designed to be one quarter wavelength long of an average frequency in a band region of an operating band width, and are spaced apart by a quarter wavelength of the midpoint of the operating band.

Abstract: An antenna comprising a ground plane having a base portion and a cylindrical obstruction that extends from the base. The obstruction is oriented such that its longitudinal axis is perpendicular to the base ground plane. The antenna also has a conducting transmission along the length of the exterior of the obstruction. A feedpoint located near the base ground plane transmits a voltage signal between the transmission element and the exterior of the obstruction. A short circuit is provided between the transmission element and the obstruction at a point distal to the feedpoint.