Abstract: A patch antenna is formed of one or more flat disc-shaped radiators disposed parallel to and spaced apart from a common ground-plane element. At each radiator, there is a feed assembly of two feeds positioned to one side of a center of the radiator in space quadrature and excited in phase quadrature for generating circularly polarized radiation from the radiator. Each of the feeds, in a preferred embodiment of the invention, is formed as a post extending through an aperture in the ground-plane element partway to the radiator for capacitive coupling with the radiator. At each radiator, a reactance element on the form of a capacitive block extends from the ground-plane element partway to the radiator at a location diametrically opposite the feed assembly.

Abstract: A multiband gridded focal plane array antenna 10 is disclosed which provides simultaneous beams of multiple frequencies. The antenna 10 includes a metallization pattern 11 providing a first set of conductive edges 18 having a first length L.sub.1 and a second set of conductive edges 20 having a second length L.sub.2. The first and second sets of conductive edges are separately fed to provide the first and second simultaneous output beams at first and second operating frequencies.

Abstract: A microstrip focal plane array antenna is disclosed which includes a planar dielectric board 18 having a first surface 22 and second surface 28. A second radiating element 30 is located on the second surface 28 of the dielectric board 18 and a first radiating element 12 is located on the first surface 22 of the dielectric board 18. Energy is coupled to the first radiating element 12 from the second radiating element 30 and is reradiated by the first radiating element 12.In a specific embodiment, the second radiating element 30 is a resonator 30 at one end of a coplanar waveguide, 24, having longitudinal and traverse axes, 32 and 34 respectively. The first radiating element 12 is a microstrip patch 12 of conductive material, having longitudinal and traverse axes, 14 and 16 respectively. The microstrip patch 12 is aligned over the resonator 30 such that electromagnetic energy from the resonator 30 is reradiated as linearly polarized energy by the microstrip patch 12.

Abstract: A lightweight, low profile phased array antenna 10 is disclosed which includes an electromagnetically coupled integrated subarray in a multilayer structure with no vertical electrical connections and no phase shifters. The integrated subarray includes a first layer 11 having an array of patches 20 of electrically conductive material. A second layer 15, is provided, in parallel registration with the first layer 11, which includes an array of resonators 22, each resonator 22 being electromagnetically coupled to a corresponding patch 20 in the first layer 11. A third layer 19 is provided which is in parallel registration with the second layer 15. Electromagnetic couplers 24 and 34 in the second and third layers 15 and 19 couple energy received by resonators 22 in the second layer 15, to processing circuitry in the third layer 19. The antenna of the present invention is adapted for transmit and receive modes of operation.

Abstract: An assembly of waveguides and coupling apertures located within walls separating the waveguides is formed within a planar configuration. The coupling apertures are arranged either singly or in pairs, with one coupling aperture behind the other coupling aperture, to provide for a division of power between waveguides and to provide for a crossing over of power from one waveguide to another waveguide. The waveguide assembly is reciprocal in operation so that the single coupling apertures may be employed for a distribution as well as for a combination of electromagnetic waves. Phase shifters may also be included to provide a desired phase relationship among waves outputted by various ones of the waveguides. The waveguides, the walls separating the waveguides, the coupling apertures and the phase shifters may all be fabricated in a parallel array within a common metallic plate by automated milling machines for facile, accurate, and reproducible manufacture of the wavguide assembly.

Abstract: An array of horn antennas with non-uniform aperture sizes is disclosed wherein the individual horns phase track over a wide frequency band. The horn with the smallest aperture is considered the reference horn, and its length defines the overall horn length of the other horn in the array. The flare lengths of the other horns of the array are less than the length of the reference horn, and lengths of waveguide are added to the other horns such that the respective combined flare lengths and waveguide lengths of each of the other horns equals the horn length of the reference horn. The respective lengths of the flare and the waveguide section are chosen such that the resultant horn antenna phase tracks the reference horn over the frequency band.

Abstract: A crossover for microwave electromagnetic radiation is constructed in a planar configuration for the transference of all of the power of a wave in a first transmission line to a wave in a second transmission line. The crossover is formed of two pairs of cross arms wherein, in each pair, the arms are spaced apart by an electrical length of ninety degrees along the first and the second transmission lines, and couple power of the waves between the first and second transmission lines with an introduction of a quarature phase relationship. The impedance presented to a wave of a cross arm is less than the corresponding impedance of the first and the second transmission lines by a factor of the square root of two to inhibit the generation of relections at junctions between a cross arm and the first or the second transmission line. Each junction provides for a diversion of one-half the power of the wave from the first or the second transmission line to a cross arm.