Abstract: A low cost tapered horn with desirable equal E and H plane pattern beamwidths is achieved with one or more annular channels in the tapered wave translation surfaces of the horn. These channels extend concentric and parallel with the axis of symmetry of the horn to permit the horn including the channels capable of being formed using molding techniques.

Abstract: The present invention relates to vertical antenna systems employing an improved artificial ground system. In a low frequency design, the artificial ground system provided is in the form of a counterpoise or ground screen that is provided with an efficient, economical and practical electrical radial wire design. A high frequency design is also provided in the form of an integral antenna structure. This high frequency integral design entails a vertical antenna, a counterpoise in the form of a metal plate, a ground plate, and wherein said metal plate forming the counterpoise is insulated from the ground plate. In either type of antenna system, the counterpoise functions to collect antenna return currents and direct them back to the feed point of the antenna in an efficient and effective manner.

Abstract: A dual antenna is provided for energizing and receiving a response from a closely coupled marker providing an identifiable signal. An elongated drive coil is wound on a substantially flat winding template and defines a longitudinal axis of the antenna. Each winding of the drive coil extends in a plane substantially perpendicular to the longitudinal axis. A receive coil has at least one elongated loop extending substantially parallel to the antenna axis with a first portion of the loop being overlapped by the drive coil; said first portion extending substantially perpendicular to the longitudinal axis of the antenna. One portion of the receive coil is outside the drive coil; the drive coil being substantially the same length as the marker with the receive coil being substantially as wide as the marker to optimize the signal. In one embodiment, a plurality of receive coil loops is provided to decrease the longitudinal sensitivity.

Abstract: A sinuous antenna having N identically generally sinuous arms extending outwardly from a common point and arranged symmetrically on a surface at intervals of 360.degree./N about a central axis. Each antenna arm comprising cells of bends and curves. Each cell being interleaved without touching between adjacent cells of an adjacent antenna arm.

Abstract: An antenna is disclosed which is particularly suitable for use with a cellular mobile phone. The antenna may be mounted on the rear window of a vehicle, and it includes a current fed one-quarter wavelength radiator adapted for mounting on one side of the window. An electrically conductive inner transfer member is mounted on the inside of the window in alignment with the radiator and a pair of spaced field-cancelling conductors are attached to the inside of the window and are spaced from the inner transfer member. The central conductor of an RF coaxial cable is coupled to the inner transfer member and the surrounding ground conductor of the coaxial cable is coupled to the field-cancelling conductors. In one embodiment, the one-quarter wavelength radiator comprises a pair of parallel, spaced radiator elements. RF energy is transferred through the vehicle window and the drilling of a hole for coupling the radiator to the coaxial cable is unnecessary.

Abstract: A plural band telescopic antenna, including a band for frequencies much higher than the frequencies of the AM/FM band, is realized by making one telescopic section into a dipole high frequency antenna with its coaxial cable feed line extending through the telescopic antenna to the feed point of the one section. A double-tuned dipole embodiment and different arrangements for coupling the feed line through a rotational drive force applying mechanism are shown. In one embodiment, the line feed is also used for coupling mechanical extension and retraction forces to the one section.

Abstract: A tuned resonant circuit including inductive and capacitive components useful as a marker in electronic article surveillance systems, comprising a laminate of a dielectric sheet having a conductive layer on one side configured to form at least one multi-turn inductive spiral. The sheet is folded back upon itself at a fold line which is precisely defined by spaced apart areas of the conductive layer such that desired portions of the layer become precisely and uniformly juxtaposed.

Abstract: A radio frequency antenna element is provided comprising a waveguide having disposed within and adjacent to a rearward portion of such waveguide a ridge, such ridge having a relatively narrow forward portion and a plurality of feeds, disposed within the waveguide, for coupling energy from a plurality of sources to a relatively wider, rearward portion of the ridge. The waveguide has a pair of opposing, relatively wide upper and lower walls and a pair of opposing, relatively narrow side walls. The relatively wider, rearward portion of the ridge tapers to the narrower forward portion of the ridge in a plane parallel to the upper and lower walls of the waveguide. The narrow portion of the ridge tapers towards one of the wider walls as such ridge extends from the rearward portion of the waveguide to the forward portion of the waveguide.

Abstract: A compact, lightweight, wideband, wing-conformal phased-array antenna structure, the array elements of which are identical, log-periodic arrangements of electrically small, folded-monopole elements printed on both sides of a dielectric substrate. A significant reduction in the height of the array elements makes this array configuration feasible for many airborne applications.

Abstract: A structure for selectively transmitting electromagnetic energy therethrough which comprises a relatively thin insulative substrate having front and rear surfaces. The surfaces each have a pattern of regions thereon in each of which a first metallized Jerusalem cross is formed. In each region additional metallized Jerusalem crosses are formed in each of the quadrants of the first Jerusalem cross. The dimensions of the Jerusalem crosses on each surface are selected to provide suitable transmission resonances so as to permit transmission of electromagnetic energy through the surface over a selected portion of the frequency spectrum and to prevent transmission outside said portion of the spectrum.

Abstract: This invention concerns an antenna switchable between the VHF and UHF frequency bands. This antenna incorporates a capacitive element, disposed at a specified distance from a reflecting surface mounted on the body of the vehicle. For VHF, tuning is obtained by a fixed self-inductance in parallel and a variable self-inductance in series with the capacitive element. The latter comprises various sections which can be short-circuited by switches. For UHF, the variable self-inductance is totally short-circuited and the fixed self-inductance is disconnected by a switch; then, plates form, with the reflecting surface and the capacitative element, a "manchette" antenna. This switchable antenna can in particular be mounted on an airplane.

Abstract: A dual mode broadband antenna especially designed to provide an omni-directional low angle or high angle radiation pattern which is predominately horizontally polarized is disclosed herein. This antenna utilizes four wire radiators in the form of an inverted conical log-spiral supported in a vertically extending fashion a predetermined distance above the horizontal ground plane. In order to alternatively operate the antenna in its high and low angle modes, first and second oppositely phased AC currents are applied to the radiators in two different ways using a simple switching device rather than a more complicated network of four hybrid circuits.

Abstract: A hinge (5) having a first, relatively stationary yoke (8) and a second, relatively rotating yoke (10). A torquing means (17) fixed with respect to the first yoke (8) transmits torque to the second yoke (10) via a block (18) retained within a cavity (20) of an elongated hinge pin (15) that is aligned along the axis of rotation (z) of the two yokes (8, 10). The torquing means (17) is coupled to the hinge pin (15). The yokes (8, 10) self-align about two orthogonal axes (x, y) that are also orthogonal to the axis of rotation (z). The block (18) is free to pivot within the cavity (20) about the x axis, while the second yoke (10) is free to pivot about the y axis about the hinge pin (15) and block (18).

Abstract: In order to achieve temperature compensation in a microstrip linear array, the array is periodically loaded by means of a plurality of open circuited stubs coupled to the main transmission line through tightly controlled gap dimensions to provide increasing shunt susceptance which compensates for the decease in shunt susceptance of the line as temperature increases.

Abstract: An antenna is pivoted on a mounting about a first axis (3) and is driven by a screw threaded drive member (5) to which it is pivoted about a second axis (4). The drive member (5) engages a drive mechanism (6) which is pivoted about a third axis (7) all the axes being parallel. At one position of adjustment (illustrated) the second and third axes (4,7) are in line with each other enabling the drive member (5) to be pivoted to the position shown in broken lines thereby doubling the size of the arc through which the antenna can be rotated.

Abstract: A multilayer antenna aperture polarizer comprises a single continuous electrically conductive trace on a flexible thin dielectric strip, the trace being formed into a plurality of arrays of grid lines with adjacent arrays interconnected by shorting leads and with a ground lead connected to the last or end array. The strip and shorting leads are folded at the locations of the shorting leads to form a stack of plane parallel polarizer panels, each comprising an array on the strip, adjacent panels in the stack being spaced apart in a direction transversely of the planes of the panels by insulator spacers, respectively. The polarizer is inserted in front of the aperture of the antenna and the ground lead is electrically connected to the antenna frame for grounding the several arrays. The shorting and ground leads are located at the corners of the stack in the neutral or minimum field zone of the antenna.

Abstract: The invention relates to a plane periodic antenna, wherein it comprises a conductive plate having radiating elements formed from two lines of flat teeth, whereof the dimensions are deduced from one another on the basis of a homothetic transformation of ratio .tau. and expansion pole O, the teeth of one of the two lines being inserted between the teeth of the other line and the end of one given tooth being separated from the edge of the plate located between two teeth of the other line by a predetermined gap, a supply line place in a plane close to that of the plate making it possible to supply the teeth, from the predetermined gap, a ground plane located at a distance from each tooth varies as a function of the wavelength of each tooth.

Abstract: A spatial filter is provided for electromagnetic waves with circular polarization comprising three parallel conducting networks, the central network being totally reflecting for a rectilinear polarization of given direction and having a non zero reflection coefficient for a rectilinear polarization having a direction perpendicular to the preceding one.

Abstract: An improved miniature antenna is disclosed which provides an electrically short radiation pattern by providing shielding of selected portions of a current carrying conductor forming a loop antenna. The shielding is provided so that the shielded portion of the loop antenna does not cancel the radiation from an unshielded radiating portion of the antenna, thereby producing a uniform radiation pattern. A plurality of the current carrying elements formed by the shielded and unshielded portions may be coupled in a series and parallel relationship to provide optimum impedance matching at the frequency of operation of a transmitter or receiver.

Abstract: A pair of facing channel members, or a short length tube saddle about the upper end of a vertical post and pivotably mounts a rocker assembly in the form of back to back channel bars. A bolt projects across the top of the facing channel members or tubes to locate the rocker bar and facing channel member or tube on the top of a vertically upstanding post. Right angle ball and socket mounts within end plates joining the rocker assembly back to back channel bars have projecting bolts received within paired frame tangs projecting outwardly from an open frame rigidly mounted to the dish antenna. The upper frame tang bears a slot to permit declination adjustment. The sweep, azimuth and latitude axes intersect each other to provide the lowest possible center of gravity for the antenna mount and minimize the moment arms for the members forming the same to thereby provide a highly rigid, heavy wind resistant support for the dish type antenna.