Abstract: A dual frequency antenna feed includes colinear axially spaced coaxial and circular waveguide cavities separated by a conducting portion having a high frequency rectangular waveguide therein extending radially outward. The coaxial cavity includes a tubular inner conductor having a polarization rotator connected to the rectangular waveguide for propagating high frequency energy. Four small coaxial transmission lines equiangularly disposed about the cavity axes and terminating in probes about a quarter wavelength from the end of each cavity intercouples the circular and coaxial cavities. The end of the coaxial waveguide cavity forms an aperture for high frequency energy from the conducting inner tube and for the low frequency energy from the region between the conducting inner tube and the cylinder surrounding the outside of the cavity. The radiating aperture is surrounded by a set of concentric conducting rings.

Abstract: A wavelength separator for separating various electromagnetic signals in such a manner that the separated signals are not seriously attenuated or altered. Ideally, the separator functions best when the ratio of long-wavelength and short-wavelength is greater than 100.

Abstract: A circularly polarizing antenna feed comprises a feed waveguide having a short circuit reflecting plate at one end and a radiating horn at the other, a wave exciter for launching linearly polarized plane waves axially along the feed waveguide in opposite directions, and a grid of parallel reflector strips disposed in a plane which is perpendicular to the waveguide axis and which is located between the wave exciter and the reflecting termination at a distance of approximately .lambda.g/8 from the exciter and approximately .lambda.g/4 from the termination. The reflecting strips of the grid are inclined at an angle of 45.degree. to the direction of polarization of the waves propagated by the exciter, the grid and the reflecting termination together forming a twist reflector which effectively reflects and rotates through 90.degree. the waves incident upon the grid. These reflected waves together with the forwardly propagated waves from the exciter represent circularly polarized waves.

Abstract: A dual band, phased array antenna especially adaptable for tactical radar capable of performing search, track and identification in a hostile jamming environment. The dual band array antenna is essentially two antennas sharing a common antenna aperture. The two antennas possess separate feed system and beam steering control. Thus, the beams for each frequency band can be steered independently and simultaneously. This design utilizes an ultra-wide band radiating element which can operate over approximately an octave bandwidth encompassing two adjacent microwave bands. In particular, the dual band signals can be received efficiently by the radiating element. A dual band coaxial-to-waveguide transition can be used to carry the signals to a diplexer. The dual band signals are separated at the diplexer and can be processed in separate feed networks.

Abstract: A compact adaptor is provided for making transition from ridged waveguide to rectangular waveguide while simultaneously imparting spatial reorientation of associated electric and magnetic fields. The adaptor is especially useful for feeding a phased array of radiating slots (or other structures) where adjacent radiating structures are preferably spaced from one another on the order of a half wavelength and fed with the magnetic field vectors oriented parallel to such inter-element array spacing dimensions. In the exemplary embodiment, a transition from double-ridged waveguide to rectangular waveguide is effected through an electrically short (e.g., 1/8th to 1/4th wavelength) non-resonant cavity using oppositely tapered continuations of the ridged waveguide walls (acting as a TEM parallel transmission line) to opposing walls of a rectangular waveguide port which is spatially oriented transverse to the ridged waveguide.

Abstract: A dual band array antenna is disclosed having interleaved waveguide and dipole arrays, each operating in a different frequency band. The orientation of the waveguides and dipoles is such that polarization of the signals of the two frequency bands is perpendicular to each other, thus reducing mutual coupling. The waveguides are used for the higher frequency band and their cutoff frequency is selected to be above the lower frequency band at which the dipoles operate, in order to reduce mutual coupling into the waveguides. In one embodiment the dipoles are printed on a substrate having a dielectric constant selected so that dipole spacing is the same as the waveguide spacing. This eliminates grating lobe formation in the radiation pattern of the waveguide array. A low pass filter is included in the dipole feed circuit to reject the frequencies at which the waveguides operate.

Abstract: A dielectric trough waveguide antenna composed of a metallic guide having a dielectric substrate covering the bottom of the guide and a plurality metal radiators placed periodically on the dielectric at the dielectric-air interface provides a low loss antenna suitable for millimeter wave applications.

Abstract: A generally fan shaped electrically conducting base member defining a waveguide cavity with a waveguide input/output in communication with the cavity at the apex thereof and a plurality of output/input waveguides in communication with the cavity equal angularly spaced along the arc of the base member. The inputs and outputs are formed in the plane of the cavity so that losses are substantially reduced and all of the output/input waveguides are equally spaced along radii of the base member and are of equal length so that signals at the outlets thereof are of equal amplitude and phase without requiring phase shifters and the like.

Abstract: An electronically scannable microwave antenna having a minimum physical size suitable for mounting in the leading edge of an aircraft wing or the like. A multiplicity of waveguide radiators form a horizontal array having a common horn for limiting the vertical beamwidth. The radiators are fed by a common continuous sinuous waveguide having a plurality of coupling apertures for feeding the radiators in phase. The sinuous waveguide includes coupling sections above and below the radiators to minimize the horizontal size of the antenna. The coupling apertures are formed to provide a linear Taylor distribution of energy to the radiators to produce a narrow horizontal beamwidth having very small side lobes. The antenna beam is scannable in azimuth by varying the frequency of the input signal or by periodically varying the phase of a constant frequency input signal at each radiator.

Abstract: A primary radar antenna has a secondary radar antenna or an IFF antenna integrated therewith. Excellent properties with respect to compactness, radiation and frequency dependency are achieved by providing a bilevel pillbox antenna having radiation deflection on a cylindrical parabolic reflector from one interplate space to another. The lower interplate space has, in proximity of the primary radar signal radiator, which is arranged with its radiation center in the focal line of the parabolic reflector, an additional feed for in-coupling of the IFF signal. The antenna is particularly suited as a combined primary and IFF radar antenna for smaller vehicles.

Abstract: An antenna for the short-range reception of an emitted signal comprises at least two independent sectors for the coarse location of an emission-beam source in two predetermined directions. Each sector is constituted by a waveguide having a single open face oriented in the intended direction of surveillance. A microwave diode is placed within each sector at right angles to, and at the geometrical center of, the supporting wall of the waveguide which is associated with the diode. The frequencies detected by the antenna are within the range of 10.sup.9 Hz to 30.times.10.sup.9 Hz.

Abstract: An antenna array comprising a plurality of antenna elements formed from ml-clad boards and conductive pins. Two metal-clad boards are placed together to form a sandwich, the metal-clad surfaces of the boards forming the top and bottom walls of a waveguide. Pins are placed perpendicular to the clad surfaces to form the sidewalls. The signal is introduced by a coaxial probe in the broad wall of the waveguide in a conventional manner. A row of pins defines the backwall of the waveguide.

Abstract: A wide band monopulse antenna includes a plurality of contiguous square quad-ridged waveguides arranged in a geometric array. Proper orientation of the array permits connection to circuitry to permit use of the individual waveguides for development of azimuth, elevation and sum pattern signals. Further, orientation of concentric arrays permits extension of the frequency band.

Abstract: A means for retaining radar elements in a structural configuration for a sed array. The elements are inserted in connectors and are held between two cap plates. The array face and retention configuration is to satisfy electrical and mechanical requirements in order to minimize surface-wave propagation and to predict scanning performance.