Abstract: Disclosed is a phased array for steering an electromagnetic wave, which includes a first layer of active material, including parallel first inner and outer surfaces, and a second layer of active material, including parallel second inner and outer surfaces which are also parallel to the first inner and outer surfaces, the second layer being adjacent to the first layer. An electrically conductive ground plane of indium tin oxide is disposed between the first and second layers and in electrical contact with the first and second inner surfaces. A first series of spaced parallel electrodes, each of the electrodes being in the form of a thin strip of indium tin oxide, is deposited on the first outer surface, while a second series of spaced parallel electrodes, each of these electrodes also being in the form of a thin strip of indium tin oxide, is similarly deposited on the second outer surface but is orthogonal to the first series of electrodes.

Abstract: A plurality of metallic wire conductors are fitted in shunt along a shorted wave guide parallel to a dielectric field of electromagnetic wave incident to the wave guide. At least some of the wires have diodes mounted on them such that selective biasing of the diodes renders these wires discontinuous and causes a controlled phase shift of the incident wave.

Abstract: Disclosed is an antenna system designed to operate in two frequency ranges imultaneously, namely S-band (1660 to 1700 MHz) and X-band (8500 to 9600 MHz). The system comprises two separate antennas which are conically scanned and share a common parabolic reflector within a radome. The S-band antenna is adapted for passive angle tracking and reception of radiosonde data by means of a balun fed dipole feed system which includes an offset hemispherical reflector which is rotated by a scan motor to provide conical scanning. The X-band antenna comprises an active feed system which includes a stationary feedhorn and a tapered dielectric lens which is coupled to the S-band hemispherical reflector and is rotated therewith about an axis through the vertex of the parabolic reflector. The tapered lens tilts the constant phase front of the X-band radiation pattern thereby producing a displaced phase center near the focus of the antenna to implement its respective conical scanning operation.

Abstract: An antenna, preferably operable in the microwave range, comprising a disc-shaped lens having a radially varying refraction index, and having feeders distributed around the circumference. Each feeder is in the shape of a thin wire having a projection which, as seen radially relative to the center of the disc, forms a straight line inclined 45.degree. relative to the plane sides of the disc. All feeders are inclined in the same direction relative to the center of the disc and thus all diametrically-opposed feeders are oriented substantially perpendicular to each other. Because of this orientation, radiation focussed by the lens passes to and from any active feeder without being substantially disturbed by other feeders, and a plurality of feeders can be active simultaneously.

Abstract: A dichroic antenna scanner is comprised of transmission or reflection surfaces that impart to an incoming wave a phase shift which varies across the surface of the antenna. For this purpose, a multilayer dichroic structure may be configured to have a controlled tapered spacing between the various layers or a variable reflectance across the dichroic surface, thereby varying the cut-off frequency of the dichroic surface across its surface. Since the phase of a transmitted or reflected wave varies rapidly in the vicinity of the cut-off frequency, a variation in the cut-off frequency across the dichroic surface yields a varying phase characteristic across the antenna.

Abstract: A system for correcting for dispersion in a beam radiated by a flat microwave antenna due to variations in the frequency of operation by providing an electronically controlled phase shift of the beam in the plane of the dispersion. The methods consist of combining with the flat antenna a matrix of particular wire conductors of which certain are controlled such that the phase shift introduced by the matrix is able to correct for the dispersion of the flat antenna.

Abstract: A lens antenna of Luneberg type comprising a disc shaped dielectric element having radially varying diffration index or dielectric constant and surrounded on both plane sides by conductive metal planes. The antenna is preferably adapted for transmission of a wave which is polarized in an angle of 45.degree. relative to the plane of the lens element and is characterized in that the distance between the conductive planes to an essential extent is formed by air or a dielectric having a corresponding dielectric constant.

Abstract: A three-dimensional bootlace lens with minimum possible focusing aberrati, minimum possible focusing size and minimum possible dielectric loading. The feed and lens surfaces are in the shape of a spherical cap and covered by contiguous arrays of radiators. The region between the inner surfaces of the lens is filled with a nonuniform dielectric material with an index of refraction which constantly changes from the center line outwardly. Lens ports are connected to a radiating antenna array by means of coaxial transmission lines all of which have the same length. The axial feed point has a focusing performance which is perfect. For all other points the lens is free of all first-order aberrations except coma. The outputs of the lens can be used to feed a planar radiating antenna array so as to produce a multiple directive beam in one angular dimension or to feed a circular array so as to make it amenable to scanning or multibeam feed systems that are used with linear arrays.

Abstract: A periodic array for use as an electromagnetic energy resonant array or reflector having a high density pattern formed from individual chevron shaped elements. Various interlocked and interlaced patterns of elements provide the array designer with more flexibility in controlling bandwidth and stabilizing the functional relationship between frequency and the angle incidence with the electromagnetic energy. Furthermore, structural patterns of chevron shaped elements readily incorporate structural paths for lightning conduction and mechanical support without severely altering the electrical performance.

Abstract: A feed system for scanning focal plane antenna systems with which a variable focal spot illumination may be achieved within the focal region of a primary antenna over a limited scanning sector is disclosed. An array of collector elements positioned to receive radiation from a scannable feed antenna is coupled to an array of radiator elements positioned in the focal region of the primary antenna, the positioning of the radiator and collector elements are such that the focal spot illumination is caused to vary with the scan angle of the antenna.

Abstract: A feed system for a geodesic Luneberg lens antenna system is disclosed, in which sequential cyclical scanning of a plurality of feed sectors of the lens from one transmitter/receiver is achieved with a minimum of dead time between successive scans.

Abstract: A lens system is formed of spaced coaxial hyperboloidal primary and secondary lenses, each having a convex surface described by a hyperboloidal eccentricity equal to the refractive index of the lens with the lenses mounted with their convex surfaces facing each other, and with the lenses having equal beam deviation factors. A feed array is integrated with the secondary lens, with the feed array comprising array elements printed on a substrate which, in turn, is backed by a ground plane. A beam forming and control network is directly connected to the substrate at the ground plane.

Abstract: A system for discriminating between signals arriving on the mainbeam of a collecting antenna and signals arriving on the sidelobes of the antenna is disclosed.

Abstract: Improved performance of an electronically scanned subarray antenna system is realized by tailoring the subarray pattern in a manner that reduces the undesirable effects of illumination truncation at the edge of the main array. This is accomplished by introducing variable attenuators into individual feed elements to effect an illumination intensity taper of the feed element array output. The improvement permits effective utilization of deterministic and adaptive nulling at both the main array and the subarray levels and further provides a system ability to scan over wide spatial angles with wide bandwidths and low sidelobes. The technique is adaptable to both space fed and constrained subarray antenna systems.

Abstract: A printed circuit parallel plate radio frequency lens having a portion of its beam ports formed with a dielectric wedge disposed between a second and third dielectric material. The dielectric constant of the wedge is different from the dielectric constants of the second and third dielectric materials. Energy introduced into such beam port is separated by the dielectric materials and is directed toward array ports of the lens.

Abstract: An electromagnetic lens for a commutated scanning beam antenna has a plurality of petal-shaped parallel plate segments, connected in series, with the first petal-shaped segment adapted to receiver power at its input edge through an array of input probes connected, in a commutative switching arrangement, to a radio frequency transmitter. The last petal-shaped segment of the lens is formed into a radiating aperture or is connected to a linear array of radiating elements. Various techniques for determining petal shapes and for connecting together the petals are discussed. Stacked and folded lenses are described.

Abstract: Bipolar switches in first conductive leads mounted in a dielectric panel are divided into successive groups of alternating polarity and additional pairs of leads are positioned in the panel adjacent each first lead to couple the groups of switches in each first lead in parallel. A reduced reversed biasing of the additional leads results in the first leads being selectively rendered discontinuous by the switches, changing the electrical characteristics of the panel to shift or focus a microwave beam passing through the panel. The additional pairs of conductive leads also operate as microwave elements to increase the bandwidth of the panel.

Abstract: Antenna apparatus for representing a bearing angle includes an antenna array of N antenna elements equispaced around the arc of a circle of at least 90.degree., and preferably greater than 180.degree. in a plane for receiving microwave energy, microwave power dividing and phase transforming matrix having N input ports respectively connected to the antenna elements and a set of output ports connected to a utilization device for indicating the bearing angle of the incoming microwave energy, and a utilization device including means for measuring the phase difference between signals at pairs of the output ports for representing the bearing angle.

Abstract: A millimeter wave line scanner is disclosed providing steered fan-shaped ms from opposite faces at substantially equal angles of a semiconductor waveguide, rectangular in cross section, and having a plurality of equally spaced metallic perturbations or strips disposed on one of the two radiating sides or faces. Different angles of scan are selectively obtained by means of at least one distributed longitudinal PIN diode formed on an adjoining side of the semiconductor waveguide having electrical circuit means coupled thereto for controlling the diode's conductivity which acts to change the guide wavelength and accordingly cause a variation in radiation angle of the two equal beams radiating in opposite directions and by means coupling energy of changing frequency to the semiconductor waveguide.

Abstract: A reflectarray antenna includes a primary feed that radiates a primary wave to a plurality of radiators where the wave is absorbed. A portion of the absorbed wave is resolved into first and second mutually orthogonal components at first and second feed ports, respectively, of a radiator. The first component is transmitted with a designated phase shift via a transmission phase shifter to the second feed port. Correspondingly, the second component is transmitted with the designated phase shift via the phase shifter to the first feed port. After the components are transmitted to the feed ports, they are re-radiated by the radiator in polarization states orthogonal to the ones in which they were absorbed.

Abstract: The multiple beam, short wave planar antenna array system, which simultaneously exhibits low loss, low side lobe levels, high efficiency, and low volume in a design affording independent control of the E and H plane radiation pattern shapes is particularly applicable in microwave radiometric systems such as airborne mapping systems. The antenna system generates symmetrical, matching narrow pencil beam sensitivity patterns by using symmetrically spaced sectorial receiver horns fed energy through a hyperbolic dielectric lens, the horn array and lens residing in a TE.sub.01 mode parallel plate guide, the lens being illuminated by signals collected by a broad wall slotted wave guide array supplied with a thin, planar sheet radome mounted on the energy receiving face of the array.

Abstract: A nondispersive array antenna comprises a linear primary radiator array in the form of a slotted waveguide emitting high-frequency waves toward a linear secondary radiator array including an acute angle .alpha. with the primary array, this angle .alpha. being approximately equal to (.pi./4) -(.theta..sub.o /2) where .theta..sub.o is the angle included by the emitted beam with the perpendicular to the waveguide in the plane of radiation. The secondary array includes a row of elemental radiation receivers on the side facing the primary array and as many elemental radiation emitters on the opposite side; each radiation receiver is linked to a respective radiation emitter through a coupling introducing a predetermined phase shift between incoming and outgoing radiation, these phase shifts compensating for the phase displacement occurring along the arrays in the free-space propagation of the waves from one array to the other.

Abstract: The inventive lens focuses a plurality of radio frequency signals received by a multi-element antenna array into a coherent signal.A circular transmission cavity has probe sites located therein. The probe sites are located on radii of the circular cavity approximately one quarter wavelength of the radio frequency of interest from the cavity's perimeter. A probe pair is positioned at each probe site. The signal from each antenna element is coupled through a three port circulator to a particular probe pair via a 180.degree. coupler. Incoherent images received at the probe pair are dumped in a load resistor, whereas the focused image of the received signal is routed through the circulator and to a receiver.

Abstract: A radiated signal, received by each one of a plurality of spatially separated antennas, forming a directive array, is coherently recovered by the lens. The lens is comprised of a plurality of vertically standing and circularly arranged printed circuit panels, each of which includes a conductive strip connected at one end to each antenna. A plurality of semi-elliptical circuit panels are affixed to the vertical panels at a predetermined angle with respect thereto. Plated on the semi-elliptical panels are metal strips of predetermined length to provide the desired time delay to the antenna signals. A combining strip couples to the time delay strips and provides a combined output signal at one end of the semi-elliptical panel. The angle at which the semi-elliptical boards are affixed to the vertical boards corrects for time delay distortion caused by the placement of the combining strip.

Abstract: The present invention makes it possible to provide a guided wave antenna having a radiation pattern which can be controlled electronically, by control signals derived from a computer or any other suitable source. In this way, the directional characteristics of the antenna can be adjusted and/or scanned rapidly, without any mechanical manipulation of the antenna. In one embodiment, a guided radio wave is launched along an antenna surface having an array of elements which provide variable non-uniform surface impedance adapted to be controlled by electronic signals. For example, each variable impedance element may comprise a wave guide section having one end leading from the antenna surface. Each wave guide section may include a solid-state electronic reflection amplifier having charcteristics which can be varied by supplying control signals to the amplifier, to vary the magnitude and phase angle of the wave reflected from the reflection amplifier.

Abstract: A sum channel waveguide is excited in a TE.sub.11 mode to cause a radio frequency wave to propagate therefrom through a cylindrical multimode waveguide. The wave propagates via a discontinuity that causes the multimode waveguide to be excited in the TE.sub.11 mode and higher order modes. The multimode waveguide is coupled to free space via a dielectric lens and a cup shaped matching section, whereby the wave causes a beam to be radiated from the lens. The cavity of the multimode waveguide is contiguous with a plurality of arcuate cavities of a difference channel waveguide. The beam is deflected in response to excitation of the arcuate cavities.

Abstract: A parallel plate geodesic lens aerial in the shape of a spherical cap or a flat disc, generates scanned planar radio beams. Commutated input signals to the lens are fed via output probes located around an arc of the perimeter of the lens to an arcuate array of radiating elements. The positional relationship between the power output from the lens and the power input to the array is 1:k, where k .noteq. 1. Dielectric-filled geodesic lenses, power level and scanned beam accuracy monitoring, and complex modulation of the input power to enable simpler aerials to be realized, are described.

Abstract: A multibeam antenna having a radio frequency lens fed by a plurality of feedports is disclosed. The radio frequency lens includes a printed circuit parallel plate region and a polarizer section. The polarizer section includes a plurality of polarizer sheets separated by a plurality of layers of dielectric material, the dielectric constant of the printed circuit parallel plate region and the dielectric constant of the layers of dielectric material being selected to form substantially collimated beams, each one of such beams being associated with a corresponding one of the feedports. With this arrangement, the polarizer section is an integral part of the radio frequency lens, thereby reducing the size of the antenna.

Abstract: A geodesic lens parallel plate waveguide in the shape of a quarter-sphere is used to interconnect a linear array of transmitting/receiving elements and an array of coupling elements. Using this aerial component, scanned radio beams can be generated by a transmitting aerial if the array of coupling elements is commutatively actuated. Unused corners of the geodesic lens parallel plate waveguide may be omitted.

Abstract: A radio frequency signal direction finding system wherein radio frequency signals received at output ports of a multibeam array antenna are sequentially sampled, in response to a sampling signal, at a frequency f.sub.s. The sampled signals are fed to a receiver channel which is tuned to the sampling frequency to produce a composite signal having a frequency f.sub.s and a phase angle, relative to a reference phase angle of the sampling signal, which provides an indication of the relative signal levels received at the output ports and hence an indication of the angular direction of a source of the radio frequency signals.

Abstract: A radar antenna includes a plurality of radiators disposed near the focal point of a parabolic reflecting surface. The radiators are coupled to a sector horn waveguide via a plurality of phase shifters and a Butler matrix. The sector horn is concurrently excited in H.sub.10 and H.sub.12 modes of propagation to provide excitation to the radiators. Radiated energy from a radiator propagates to the reflecting surface and is reflected therefrom.

Abstract: Electronically steered antenna system is provided by placing a panel of dielectric material with specific thickness and dielectric constant spaced forward of an array of piezoelectric transducers. These piezoelectric transducers present a refelective surface. High frequency wavefronts are transmitted toward the dielectric panel and pass on to the reflective surface. The phase of the reflected waves depends upon the spacing of the reflective surfaces from the panel. A change in this spacing is provided by electrical control signals being applied to the piezoelectric transducers.

Abstract: A polarization controllable lens is disclosed for receiving and re-radiating linearly polarized electromagnetic energy. The lens is comprised of a pair of spaced apart multiarm/antenna elements of opposite geometric polarization. The elements are located on opposite sides of a ground plane and are spaced therefrom by 1/4 wave length. The arms of the two antenna elements are constructed of different lengths such that the right-hand circular polarized and left-hand circular polarized components of a linearly polarized signal experience different phase delays while being received and then re-radiated. As a result, the linear polarization state of the re-radiated energy is rotated by an amount proportional to such difference in lengths.

Abstract: In a microwave lens of the Rotman type for a scanning beam antenna a plurality of radiating feed probes are spaced along the focal arc. An illumination function is then commutated around the focal arc by energizing groups of the feed probes simultaneously in accordance with weighting functions to thereby cause the resulting radiated beam to scan in small equally spaced increments while the array factor remains essentially constant. Methods of calculating the weighting functions and feed probe spacing are shown.

Abstract: In a microwave lens antenna of the parallel plate type for scanning a beam wherein a plurality of feed probes spaced along the focal arc are simultaneously excited in groups in accordance with weighting functions, the phases of the feed probes are optimized by predetermination of the lengths of the coaxial cables supplying energy to the feed probes.

Abstract: An array antenna having a plurality of radiating elements coupled to a first plurality of radio frequency lenses, such first plurality of radio frequency lenses being coupled to receiving or transmitting apparatus through a second plurality of radio frequency lenses. With such an arrangement, sidelobes associated with any one of the radio frequency lenses in the first plurality thereof are reduced by the focusing effect of the second plurality of radio frequency lenses.

Abstract: An antenna assembly wherein the direction of a beam of radio frequency energy may be changed by combining the effects of a mechanically movable reflector and an electromagnetic lens is disclosed. In the preferred embodiment the antenna arrangement includes a corporate monopulse feed arranged to produce a linearly polarized divergent beam which is first reflected from a linearly polarized paraboloid to direct a convergent beam toward a mechanically rotatable polarization-twisting reflector. A selected portion of a spherical electromagnetic lens arrangement is illuminated by the still convergent beam from the latter reflector, such lens then determining the direction of the beam finally propagated in free space.

Abstract: An aperture antenna comprising at least one reflector, a primary radiator, and a plurality of movable beam-wave-guide reflectors arranged between the reflector and the primary radiator for directing electric waves from the primary radiator towards the reflector, in which at least one of the movable beam-waveguide reflectors is controlled to displace a feeding point to the reflector, and in which wavefront defocusing distortion of a radiated electric wave resulting from the displacement of the feeding point is corrected by moving at least one of the remaining movable waveguide reflectors.

Abstract: An antenna apparatus comprising a primary radiator having an axially symmetric field pattern, and a main reflector and a subreflector coupled to the primary radiator through a beam wave-guide path. The antenna rotating axis is aligned with the axis of the primary radiator but a little deviated from the polar axis or the earth. At least one movable beam waveguide reflector or electromagnetic lens is provided in a radio wave path between the primary radiator and the subreflector. The antenna rotating axis is adapted to be rotatable only within a small angular range. The beam wave-guide reflector or electromagnetic lens is moved to thereby deflect the antenna beam.

Abstract: A space-fed phased-array arrangement in which the plural antenna elements each include first and second (front and rear) individual radiators. Between these input and output radiators, there is a combined controllable phase shifter and controllable electronic switching arrangement. In accordance with external control signals, the amount of phase shift (phase delay) introduced by each element may be controlled, and by appropriate programming of these phase shifts, beam formation and pointing angle may be determined. The electronic switch devices are programmable to convert any or all of the antenna elements to reflector or retro-directing elements whereby a rear-pointing beam may be generated and scanned in substantially the same way as the forward beam is generated and scanned. In the retro-directive (reflective) mode, energy from the primary feed passes bi-directionally through the reciprocal controllable phase shifter sections.

Abstract: The polarization control of the antenna is obtained by space feeding the nals through a polarization control rotator to a monopulse feedhorn.

Abstract: An improved Lewis scanner comprising a focal lens having two best focus angles positioned with its axis at an angle other than perpendicular to the antenna aperture. The antenna aperture is maintained vertical with respect to the earth's surface to provide a planar beam at 0.degree. elevation. The focal lens axis is oriented at an angle of typically one-half the maximum elevation scan angle. The angle of the microwave reflector between the parallel plates of the Lewis scanner is changed from the conventional 45.degree. by one-half the angle between the focal lens axis and the 0.degree. elevation angle. An asymmetric feed lens improves the beam shape over the entire scan range.

Abstract: A form of printed wiring antenna with integral transmission feed line is disclosed and a passive repeater using the antenna is shown printed onto a single printed wiring card. An array of such cards can be fabricated into a radiant energy lens. The character of the lens is determined by the physical dimensions of the printed wiring cards and the electrical length of the printed transmission lines.

Abstract: An antenna system forming a cluster of closely spaced beams filling a desired angular scan sector is disclosed. A transmit signal amplitude applied to each beam is modulated as a function of time to form a composite beam which scans smoothly across the scan sector. The RF transmit signal is initially split into a plurality of equal amplitude signals and fed to a plurality of attenuators by power dividers for selective amplitude modulation of the RF signals. The amplitude modulating signals are supplied the attenuator by a digital controller which also supplies switch control signals to selectively switch amplitude modulating transmit signals of varying amplitude to selected feed elements of an array of radiating elements in a time sequence for feeding an antenna reflector.

Abstract: A planar constrained lens (bootlace lens) antenna is disclosed capable of providing a large one or two dimensional field of view with either a scanning feed or with multiple feeds. This planar constrained lens antenna is of the type which can replace both narrow field of view and wide field of view lenses in multiple beam communications satellite and in limited scan radars using focal plane scanning or with a two element lens system and a scanning phased array feed.

Abstract: An array of parametric amplifiers is optically fed pump power by a pump sce. Beam steering of the array is provided by changing the apparent phase of the pump source.

Abstract: A radio frequency multibeam array antenna is disclosed wherein a beam forming network includes a first set of vertically disposed parallel plate lenses coupled between a matrix of radiating elements and a second set of horizontally disposed parallel plate lenses. With such a beam forming network a plurality of narrow pencil-shaped beams of radiation may be formed over a relatively large solid angle.

Abstract: A rotating lens antenna seeker-head provides conical scan capability for an ntenna system while simultaneously providing a two axis scan capability by positioning rotating lens in front of a microwave antenna. A pair of rotatable lens are disposed in parallel across the beam front of the antenna system to refract the microwave beam away from the antenna boresight, providing variable scanning modes. The third wedge provides the conical scan pattern for the antenna regardless of the position of the two axis wedges.

Abstract: A phased array radar antenna comprises an array of hollow, rectangular tubes, each tube having an opening therethrough. A tuning slug is positioned within each of the hollow tubes, and is mechanically coupled with a transducer for moving each tuning slug through the corresponding hollow tube responsive to an electrical input thereto. A feed horn is provided for radiating electromagnetic energy into the openings of the hollow tubes whereby the energy is reflected therefrom in a direction and in a beam width determined by the position of all of the slugs.

Abstract: A phased-array antenna in which transmitting energy from a primary feed system is radiated through free space as a primary wave to a plurality of first radiator elements, where they are received, and conducted over a plurality of phase shift elements, which may be electronically controlled, and which convert the primary wave into a planar wave and additionally effect a desired beam deflection, with such waves being radiated by a plurality of second radiator elements, in the form of a planar wave with received energy passing in the opposite direction along the same path, in which a second primary feed system is disposed at the second radiator elements and also supplied with transmitting energy which is radiated through free space, as a primary wave, to the second radiator elements where it is received, conducted over said phase shift elements and radiated by the first radiator elements in the form of a planar wave.