Abstract: A wideband, wide angle sidelobe cancellation array system is disclosed. The system includes a main array formed of a plurality of regularly spaced elements, and an auxiliary array formed of two auxiliary antenna elements spaced from the outermost elements of the main array a distance equal to one-half the spacing of the main array elements. The received signals from the main array elements are combined to form a main array signal. The contributions from the auxiliary array elements are combined to form an auxiliary array signal. The two array signals have a good amplitude and phase match over a wide frequency and angle range. The main array and auxiliary array signals are then combined to form a system array signal wherein the sidelobe energy in the main array signal has been substantially cancelled. The system can be made an adaptive one by the addition of adaptive RF phase and amplitude weighting to the auxiliary array signal prior to combining with the main array signal.

Abstract: A shared antenna aperture has two or more sets of interleaved antenna elements. Open-ended waveguides are used for the elements of the higher frequency antenna array and are selectively interconnected to form the elements of the other sharing antenna arrays. Plates are used to short walls of adjacent waveguides to form notch antennas. Coaxial feeds are used to excite the notches at a lower frequency than the waveguides. In one embodiment, the notch antennas formed of two interconnected waveguides operate at half the frequency of the waveguides. To form a third sharing antenna, four adjacent waveguides are interconnected to form notch antenna elements and these notches are excited at an even lower frequency.

Abstract: A cavity with a plurality of notches formed in the edge of the open end. Each notch is fed to establish a notch-type antenna. Notches at 90 angles from each other are formed for a monopulse application. A coaxial feed line is used where the outer conductor is connected at one side of the notch and the inner conductor at the other side. The sizes of the cavity and notches are selected to radiate energy of a selected frequency bandwidth. Additional cavities of different sizes for radiating different selected frequencies are nested concentrically together to form a multifrequency antenna array with a common phase center. Each cavity has a plurality of notches and each cavity may be rotated in relation to the adjacent cavity to misalign the notches between the two cavities and thereby increase isolation between frequency bands.

Abstract: Disclosed is a circular waveguide in which a slots are formed which are shaped and disposed such that they interrupt either the right hand or left hand circulating mode (RC and LC respectively) residing in the waveguide. Locating the slots in the waveguide wall is accomplished in accordance with the theory that for TE modes in circular waveguide with circumferential variation of e.sup..+-.jm.phi., current flow lines are produced that are helical. The slots are located so as to interrupt the helical current of the desired mode. In one embodiment, an ortho-polarization mode transducer and a circular polarizer are used to feed the slotted waveguide. By control of the amplitude and phase of the energy propagating in the waveguide, azimuthal pattern control can be effected. By dielectric loading the waveguide to make .lambda.g in the loaded waveguide equal to .lambda.-free space, endfire radiation can be achieved.

Abstract: Disclosed is a circular waveguide in which a slots are formed which are shaped and disposed such that they interrupt either the right hand or left hand circulating mode (RC and LC respectively) residing in the waveguide. Locating the slots in the waveguide wall is accomplished in accordance with the theory that for TE modes in circular waveguide with circumferential variation of e.sup..+-.jm.phi., current flow lines are produced that are helical. The slots are located so as to interrupt the helical current of the desired mode. In one embodiment, an ortho-polarization mode transducer and a circular polarizer are used to feed the slotted waveguide. By control of the amplitude and phase of the energy propagating in the waveguide, aximuthal pattern control can be effected. By dielectric loading the waveguide to make .lambda..sub.g in the loaded waveguide equal to .lambda.-free space, endfire radiation can be achieved.

Abstract: Disclosed is a power divider/combiner using two parallel plate radial transmission lines having parallel plate spacing of less than .lambda./2 and which operates in a higher order mode, preferably the first higher order circumferential mode TE.sub.11. High isolation between amplifiers coupled to the radial transmission lines at their circumferences is achieved by coupling an arrangement of circulators between the amplifiers and the radial transmission lines. This isolation arrangement reduces the effects of any spurious signals that are generated by means such as imperfections and imbalances in any active devices coupled to the radial line and permits de-energizing amplifiers as desired for lowering power output without degrading performance.

Abstract: Disclosed is a parallel plate radial transmission line having parallel plate spacing of less than .lambda./2 and which utilizes a specific higher order mode, preferably the first higher order circumferential mode. Undesired modes are suppressed by mode supression slots formed in one or both of the parallel plates and which are oriented parallel to the current flow lines of the particular mode that is used. These slots have a negligible effect on the mode being used but they couple out other modes that are generated by means such as by imperfections and imbalances in any active devices coupled to the radial line. A centrally located feed is used to launch circularly polarized energy of the TE.sub.11 mode in the particular circumferential mode in the radial line. The feed may also receive circularly polarized energy of the particular circumferential mode in the radial line, linearly polarize that received energy and conduct it in the TE.sub.11 mode.

Abstract: A differential phase shifting structure is disclosed, employing corrugated ridges in square or round waveguides or in coaxial lines operating in the TE.sub.11 mode. The structure provides a substantially constant differential phase shift between two waves polarized orthoganally to each other. The corrugations in the ridge provide a series inductance which can be optimized with the shunt capacitance of the ridge to provide a characteristic impedance matching that of the unloaded structure. The corrugated ridges provide increased differential phase shift per unit length. The differential phase shifting structure is particularly well suited to such applications as circular polarizers, quarter wave plates or polarization rotating half-wave plates.

Abstract: An electronically scanned array antenna useful for millimeter wavelength energy is disclosed. The antenna comprises a fully ferrite loaded square or round waveguide having radiating apertures spaced along part of its length. Rf energy is circularly polarized in the waveguide. The phase velocity of the wave is controlled by applying a longitudinal magnetic field to the ferrite to produce a controllable linear progressive phase of the energy radiated from the apertures to form a beam in the desired direction. The phase control is of a latching type using flux drive. The particular structure of the invention enables combining a plurality of branching array elements with a feed element to form an array capable of two dimension beam scanning.

Abstract: A particular plastic material is formed into the desired component shape and then is plated by a process comprising; a particular surface preparation step, electroless deposition and electrolytic deposition which results in excellent plating adhesion. The plated component is then assembled with other components manufactured in the same manner or with compatible metal components such as aluminum and soldered together in a disclosed hot oil dip soldering process. In the soldering process, the plated plastic substrate is completely immersed in a hot oil medium at a temperature of approximately 243.degree. C. (470.degree. F.) for a time of approximately 60 seconds for solder reflow.

Abstract: A particular plastic material is formed into the desired component shape and then is plated by a process comprising; a particular surface preparation step, electroless deposition and electrolytic deposition which results in excellent plating adhesion. The plated component is then assembled with other components manufactured in the same manner or with compatible metal components such as aluminum and soldered together in a disclosed hot oil dip soldering process. In the soldering process, the plated plastic substrate is completely immersed in a hot oil medium at a temperature of approximately 243.degree. C. (470.degree. F.) for a time of approximately 60 seconds for solder reflow.

Abstract: A millimeter-wave phase shifter for use at high millimeter-wave frequencies is disclosed. The phase shifter employs continuous aperture ferrite and corrugated horns to make a reciprocal phase shifter in the frequency range of interest. Applied linearly polarized energy is expanded in cross-section by means of a first corrugated horn. The expanded energy is focused by a first lens, circularly polarized and applied to a ferrite phase shifting section. The phase shift applied to the energy is controlled by means of phase control circuitry and a yoke and coil arrangement. The phase-shifted energy is then converted to linearly polarized energy by a second circular polarizer focused by a second lens and contracted in cross-section by a corrugated horn. The use of the corrugated horns, polarizers, lenses and ferrite phase shifting components allows a much larger device to be fabricated and hence physical tolerances are reduced by an order of magnitude for the frequency range of interest.

Abstract: A power-radiating slotted waveguide comprises one or more rods mounted inside the waveguide adjacent a non-inclined slot. The rod causes power to be radiated and because the slot is non-inclined, undesirable cross-polarized radiation is minimized. The energy radiated from the slot can be varied by varying the area between the rod and the waveguide walls.

Abstract: A broadband group delay waveguide lens utilizing an array of half wave plates is disclosed. The lens is comprised of an array of uniformly spaced sections of waveguide having various lengths. The waveguide lengths are selected so as to provide an equal time delay to all rays from the focal point to the aperture plane of the lens. Since equal time delay does not ensure equality of phase at the aperture plane, half wave plates are inserted in the waveguide elements for adjusting the phase of each ray to obtain a constant phase plane over the aperture plane at the design frequency. The inner surface of the lens is spherical with the radius of the sphere equalling the focal length of the lens. The outer surface may be ellipsoidal having a semi-minor axis equal to the focal length and the semi-major axis is dependent upon the waveguide cross section dimensions and the design frequency. Such a lens has a low aperture phase error over a relatively large frequency range.

Abstract: An antenna feed system having a very wide (multi-octave) bandwidth. The antenna feed comprises a plurality of nested annular cavities each parasitically excited by a pair of orthogonal two-point fed dipoles. The frequency selective properties of the dipoles and the annular cavities in conjunction with the focal distribution of the reflector or lens with which the feed is used results in a multiplexing of sub-bands across the total bandwidth. A modification of the end members of the two-point fed dipoles permits dual-plane and dual polarization monopulse operation of the feed system.

Abstract: A dual frequency band horn-type antenna feed is described which has primary application to optimally illuminate a parabolic cylindrical reflector operating simultaneously at high power in both of the two bands. The principle of the invention is applicable to any two frequency bands regardless of their frequency separation including coincidence as a limiting case. The basic requirement of such a feed is that it must be as directive as possible within constraint of the feed aperture size in the plane of the cylinder axis because the cylindrical reflector does not collimate the beam in this plane and it must be relatively nondirective in the plane of the parabola for efficient illumination of the reflector. This requirement requires the phase front in the directive plane to be controlled within a small fraction of a wavelength at both frequencies.