Abstract: A dual band omni directional antenna is disclosed. A dielectric cylinder supports a cone shaped reflector over a corrugated radio frequency horn. Orthogonal mode transducers produce and conduct circularly polarized radio frequency waves within the horn. The reflector, the horn, and the transducers are all coaxially disposed. The antenna produces a torodial radiation pattern in a plane that is substantially orthogonal to the axis of the antenna. Transmit and receive functions may be performed simultaneously using a single reflector and two orthogonal mode transducers.

Abstract: A dual mode waveguide orthomode transducer has a section of circular waveguide (12) and a transition (16) from circular waveguide to rectangular waveguide disposed coaxially along a longitudinal axis (38). A terminus of the transition (16) opposite the circular waveguide (12) serves as a straight port (46) for input signals, and at the opposite end of the circular waveguide there is a front port (14) for outputting electromagnetic signals. A side port (48) connects via a tapered rectangular waveguide (40) perpendicularly to the longitudinal axis (38) to connect with the circular waveguide (12), and to couple electromagnetic energy into the circular waveguide (12) via a window (50) disposed in a sidewall (42) of the circular waveguide. A plane of polarization of a wave in one input port is perpendicular to a plane of polarization of a wave in the other input port.

Abstract: A circularly polarized wave entering the horn is converted to a linearly polarized wave which appears in one of the ports depending on the sense of the polarization. The stepped configuration of the impedance matching section minimizes mutual coupling among horns of the respective assemblies of the array antenna.

Abstract: A flat cavity RF power divider wherein a flat cavity and an input waveguide share a common wall, coupling slots being disposed in the common wall offset from the centerline of the input waveguide for exciting a dominant TE.sub.4,0 mode in the flat cavity, the power divider also including short circuit means for exciting the transverse axis column of the flat cavity, and RF absorber means in the cavity to improve the frequency response of the divider, output coupling means also being provided for providing an RF power output.

Abstract: A bicone microwave antenna having an orthomode tee as an input/output terminal, an internal dielectric polarizer, a circular waveguide with eight longitudinal radiating slots, two 30 degree conical reflectors, an external meanderline polarizer, and a partial circular waveguide short. An RF signal from the input/output terminal is converted into a rotating TE.sub.11 mode by the internal dielectric polarizer. The radiating slots in combination with the conical reflectors radiate the RF signal as a horizontally polarized field in a doughnut-shaped pattern. The meanderline polarizer converts the horizontally polarized field into a circularly polarized field. The partial circular waveguide short leaks a predetermined amount of radiation out the end of the waveguide to fill the center hole of the doughnut-shaped radiation pattern, thus producing a hemispherical RF beam having an elevation angle from 110 to -110 degrees.

Abstract: A dual septum polarization rotator which, in the presently preferred embodiment thereof, includes a square waveguide and a pair of stepped septums disposed in spaced, orthogonal relation to each other within opposite end portions of the square waveguide. A first one of the septums extends horizontally between the side walls of the waveguide, parallel to the top and bottom walls of the waveguide, and the other/second one of the septums extends vertically between the top and bottom walls of the waveguide, parallel to the side walls of the waveguide. The first septum, in cooperation with the waveguide, defines first and second input ports, and, the second spectum, in cooperation with the waveguide, defines first and second output ports. The spacing between the first and second septums defines a central, open, nonseptum region within the waveguide.

Abstract: A waveguide hybrid includes a generally rectangular superstructure defined by first and second conductive broad walls and first and second conductive narrow walls, and an intermediate, conductive narrow wall bifurcating the superstructure into first and second generally rectangular waveguides, with each of the waveguides being provided with a central, longitudinally extending land or ridge, preferably having a generally rectangular, cross-sectional profile. A coupling window is provided in a central portion of the intermediate narrow wall, which is shared in common by the first and second waveguides. Further, a capacitive button, which preferably takes the form of a square peg, is provided on the floor of the superstructure between the lateral surfaces of the common narrow wall which define the coupling window. In operation, RF energy, such as a microwave excitation signal, is injected into the input port of the first or primary waveguide, thereby launching a TE.sub.

Abstract: A broad band omnidirectional monocone antenna 10 having a wide operative frequency spectrum and a large elevation angle A is disclosed herein. The antenna 10 of the present invention includes an input circular waveguide network 12 and 18 for providing electromagnetic energy of at least one polarization. Coupled to the circular waveguide network 12 and 18 is a dielectric-loaded waveguide arrangement 22 for projecting a first electromagnetic beam. The inventive antenna 10 further includes a parasitic element network 32, 34, and 36 positioned in the path of the first beam. The parasitic element network 32, 34, and 36 is disposed to form a parasitic beam in response to the first beam. In a particular embodiment of the inventive antenna 10 a beam shaping cone 40 circumscribes the dielectric waveguide arrangement 22. The cone 40 is adapted to augment the elevation angle A characterizing the antenna 10 of the present invention by redirecting the parasitic beam.

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: An antenna system for an array antenna includes an array of radiators formed as patch antenna elements on a dielectric substrate, there being a shielding metallic sheet on a side of the substrate opposite the radiators. A further dielectric substrate and a bottom metallic sheet are disposed on a side of the shielding sheet opposite the radiators. An antenna feed system is disposed in the further sheet. Coupling devices such as orthogonal slots, in one embodiment, or a microwave crossover in a second embodiment, couple electromagnetic power from the feed system to the radiators through the shielding sheet. In the case of the coupling slots, the feed system provides phase quadrature signals for development of circularly polarized radiation. The crossover provides only a linearly polarized wave, and is formed of two coplanar waveguides, one in the shielding sheet and one in the bottom sheet.

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 diplexer for electromagnetic signals of higher and lower frequency is formed of a common waveguide channel for both signals, the common channel branching into a through waveguide channel and a side waveguide channel. The through channel includes a filter having a pass band for propagation of the lower frequency signal and inhibiting propagation of the higher frequency signal. The side channel is formed as a waveguide below cut-off frequency with respect to the lower frequency signal for inhibiting propagation of the lower frequency signal while permitting propagation of the higher frequency signal. A coupling aperture formed as a slot resonant at the higher frequency is located in a waveguide wall at an integral number of quarter guide wavelengths in front of the filter for coupling the higher frequency signal between the common and the side channels.

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: A polarization selector system, suitable for use with an antenna for radiating electromagnetic waves at a variety of preselectable polarizations, is formed of an orthogonal mode launcher of electromagnetic waves, and a hybrid coupling assembly for driving the launcher. The coupling assembly has a pair of waveguides sharing a common wall. A set of hybrid couplers of differing coupling ratios, and including a mechanically displaceable gate within each coupler, is disposed serially along the common wall.The gates are individually positionable to provide for coupling of differing amounts of electromagnetic power with 90 degree phase shift between the waveguides.

Abstract: A quadrature hybrid coupler for coupling electromagnetic power between a first coplanar waveguide disposed on a first side of a circuit board and a second coplanar waveguide disposed on a second side of the circuit board is formed by means of a first pad and a second pad disposed in respective ones of the waveguides. The pads are formed as a widening of a central strip conductor of each of the waveguides. The pads are in registration with each other. Circumferential slots defining the pads are widened in proportion to a widening of the strip conductor to retain a characteristic impedance of the waveguides from ports of the coupler through the pads.

Abstract: A short slot waveguide hybrid coupler is disclosed wherein the coupling factor is switchable over a predetermined range of discrete coupling factors. A coupling slot formed in the common dividing wall between the contiguous first and second waveguides of the coupler allows coupling of electromagnetic energy between the two waveguides in accordance with a first coupling factor. A plurality of conductive pins are arranged for selective insertion into the coupling slot to effectively shorten the slot and thereby progressively reduce the coupling factor as more pins are inserted into the coupling slot.

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 assembly of coaxial tranmission lines and coupling devices, formed of closely spaced center conductors of the coaxial lines, is formed within a planar configuration. The coupling devices are arranged either singly, or in pairs with one coupling device behind the other coupling device, to provide for a division of power between transmission lines and to provide for a crossing over of power from one transmission line to another transmission line. The transmission-line assembly is reciprocal in operation so that the singly arranged coupling devices 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 transmission lines.

Abstract: A dual mode circularly polarized horn radiator is useful in the testing of radiation apparatus in an anechoic chamber. The horn has a buffered radiating aperture which permits a plurality of the horns to be arranged in an array with minimal mutual coupling between the horns. The radiating aperture is located at an end of a conic section, of low flare angle, and has a diameter of one free-space wavelength of the radiation to be radiated from or received at the horn. This permits use of the horn for measurement of near field radiation pattern of apparatus under test. The horn includes an orthomode tee having mutually perpendicular rectangular waveguides extending therefrom, and being coupled thereby to a circular port. A polarizer connects the circular port of the tee to the conic section, and includes two sets of diametrically opposed pins for conversion of both right-hand and left-hand circular polarizations to linearly polarized radiation.