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 method and apparatus for noninvasively locating and heating a volume of tissue, specifically a cancerous tumor, including placing a bolus in contact with the patient and substantially around an area of interest including the volume of tissue, placing an array of antennas on the bolus and substantially around the area of interest, imaging the area of interest, selecting an approximate center of the volume of tissue on said initial image, determining appropriate amplitudes and phases for the antennas, energizing each element at respective appropriate amplitudes and phases to heat the volume of tissue, repetitively imaging the area of interest to create subsequent images, and subtracting said initial image from the subsequent images to determine temperature changes in the area of interest.

Abstract: The mobile cylindrical microwave antenna array of the present invention comprises a plurality of rectangular panels when deployed forming a cylindrical array. The total number of panels forms an even number with each pair of panels, a left panel and a right panel, forming a subarray unit of the cylindrical array. These panels are hinged on the vertical outer edges to each other. The mobile cylindrical array has a center support structure which has a plurality of folding radial supports at the bottom and top of the center support structure. Each subarray unit is attached to the radial supports at the top and bottom. A motorized driver for translating is attached to each subarray unit and one radial support. When operated to collapse the deployed array, the motorized driver causes the left and right panel of the subarray unit to fold outwardly wherein the apex points to the center support.

Abstract: A multiple channel rotary joint design is described in which the channel components are laid out in a manner to reduce the number of layers of microwave circuitry necessary to provide rotary coupling with the antenna. The reduction of layers in each channel allows room for larger conductors in each channel, providing greater power handling capability. Compactness is also achieved through the use of a novel central extrusion that replaces the usual coaxial input lines, novel choke designs, and a novel stripline configuration that makes dual use of various components and minimizes losses within the joint. The central extrusion provides all the high power inputs, while allowing the passage through its center of a plurality of low power coaxial lines to low power channels residing on top of the high power channels. Cooling of the rotary joint is simplified by keeping the center of the joint stationary, and cooling air is fed through the transmission lines to make this function more efficient.

Abstract: A wide bandwidth microwave power divider is formed of a conductive enclosure having a longitudinal axis and a common wall lying therealong forming a pair of partially enclosed compartments. A pair of isolated input meander striplines having longitudinally spaced antisymmetrically disposed jogs at which power is radiated lie on opposite sides of the common wall. A plurality of output striplines one each in the vicinity of a jog are coupled to the common wall and extend outwardly of the trough. The striplines are responsive to carry the radiated signal or power from the input. A pair of parallel ground planes extend from the trough on opposite sides of the output striplines to confine the signal or power. Termination means near a proximal end of the striplines extend between the ground planes for electrically isolating the trough. A load extends between the ground planes for absorbing any imbalance in the power radiated to the striplines.

Abstract: A coupling matrix for a circular array microwave antenna is described which permits the formation and phasing of multiple beams from a circular array. The present invention provides a beam forming and steering means for a circular array which utilizes at least one radio frequency signal as an input to a matrix of passive proximity couplers. These passive proximity couplers are configured in rows and are operable to form the radio frequency signal. These couplers are interconnected into distinguishable groups.

Abstract: A radar antenna utilizes groups of high frequency patch radiating element which are configured to function at two frequencies. The groups of patch radiators are configured to have a wide bandwidth and to make efficient use of the aperture while maintaining a thin cross-section.

Abstract: An array antenna feed system which provides a constant beamwidth over a large bandwidth of operating frequencies. In transmitter applications, the applied signal is divided into correction and basic signals by a frequency sensitive splitter. The magnitudes of the basic and correction signals provided by the splitter vary sinusoidally with frequency and are displaced a quarter cycle from each other on the frequency scale. The correction and basic signals are combined in series or corporate coupler arrays to drive the individual antenna elements. Coupler coefficients are predetermined to make the complex addition of the correction and basic signals provide a resulting synthesized signal which gives the desired voltage distribution for the same beamwidth at the operating frequency limits. In receiving applications, the splitter functions to combine the correction and basic signals from the coupler array and transfer a combined signal to the receiver circuitry.

Abstract: A binary Butler matrix is expanded into a non-binary matrix coupled to a like number of non-binary antenna elements for forming multiple beams from a phased array and wherein an n.times.n Butler matrix drives n+l elements, and where the l elements are coupled to predetermined ports of the Butler matrix normally coupled to the n elements but coupled thereto through respective 180.degree. phase shifters such that, for example, the first or (n+1).sub.th element to the right of the n.sub.th element is coupled to the same port of the Butler matrix coupled to the 1st element but additionally through a fixed 180.degree. phase shifter while the first or 0.sub.th element to the left of the 1st element is coupled to the n.sub.th same port coupled to the n.sub.th element but including a respective 180.degree. phase shifter. Progressively increasing numbers of elements on either side of the n elements are respectively coupled to ascending and descending numbered ports of the binary matrix through respective 180.degree.

Abstract: A microwave phase shifting device utilizing the rotation lateral to a longitudinal axis across a square or circular waveguide by a slab of dielectric material to provide a differential phase shift between a linear to circular polarization in a high frequency microwave signal.

Abstract: A strip transmission line power divider having an isolated port remote from the output ports is disclosed. Power division is provided by a two branch strip transmission line. A coaxial transmission line coupled between the output ports of the divider is coupled to an isolated port where terminating resistors of any convenient power rating may be used.

Abstract: A method of forming the far-field beam pattern of an antenna at short ranges is disclosed. More specifically, the antenna beam pattern is rotated through a rotational angle about the line-of-sight of a source of radar signalling located at a near-field range away from the antenna. Measurements of the field of the antenna are taken at predetermined angular increments during the rotation thereof. The far-field beam pattern of the antenna is formed by deriving discrete values thereof for corresponding angle increments along the angular rotation. Preferably, a multiplicity of antenna field measurements are selected about each selected angular increment based on a predetermined angular spacing. The discrete beam pattern value corresponding to each selected angular increment is derived as the weighted summation of the multiplicity of antenna field measurements associated therewith.

Abstract: A two-dimensional (2D) radar antenna system includes a combination of power divider networks coupled together to drive an array of antenna elements to form two beams in different directions spatially. The power divider networks, in combination, have characteristics which effect power concentrations of the two formed beams at different locations in the array without significant loss of illuminating power. As a result, the two formed beams render both amplitude and phase angle difference signals with respect to a common detected target which may be used to accurately and uniquely measure the elevation of the target.

Abstract: The existence and method of suppression of spurious post mode to improve sidelobe performance of an array of dipole antenna elements together with examples of geometric configuration for suppression of such post mode is described.

Abstract: A self-multiplexing antenna comprising an array of radiating elements for diating a plurality of orthogonal beams in response to wave energy excitations applied thereto. A plurality of first transmission lines are connected between respective radiating elements and respective resistive terminations. A plurality of second transmission lines are connected between respective input ports and respective resistive terminations. A plurality of directional couplers couple wave energy from each input port to each radiating element in the array via the first and second transmission lines whereby wave energy from each input port generates a separate orthogonal beam from the array of radiating elements.

Abstract: An antenna assembly with a curved reflector and feed means at one side of the focal axis of such reflector. The feed means includes a number of relatively-fixed-position feed elements spaced apart unequally to obtain signals of different phase at the reflector for forming a composite reflected beam with minimized sidelobe content.

Abstract: The steering of the beam of a rectangular directional antenna array through a small angular increment in one of the orthogonal directions of the array is achieved by the derivation and processing of a small fraction of the input power as voltage in quadrature with the unphased input power in a manner which applies a doublet of first and second opposed j-direction conjugal phase shifted components to a pair of subsets of radiating elements which are bilaterally symmetrically disposed on one and the other side of a centerline of the array. An unphased component of the input power is applied to a central subset of radiating elements therebetween. The processing of the small voltage in quadrature is performed in such a manner that a single selectively variable device causes controlled inversion of the doublet of conjugal voltage components applied to the radiating element subsets.

Abstract: A device for absorbing resonances in a large circular cavity such as a microwave rotary joint that utilizes a horizontally positioned resonance absorber positioned in the balun cavity to absorb the resonances or undesired modes. The resonance absorber forms a folded slot with a resistor across its arms to interrupt the circumferential flow of current in the rim of the cavity without affecting the normal desired mode.