Abstract: A dual mode antenna that allows both millimeter wave and infrared radiation o enter a single aperture and propagate through a common transmission device to a point where the respective energies are divided to follow separate paths for subsequent processing. An electromagnetic transmission guide or waveguide for the system comprises a tubular waveguide member, having a beam directing lens or lenses therein, for maintianing low-loss, gaussian beam propagation of millimeter wave energy therethrough. A waveguide fiber array is coupled into or adjacent to the tubular member at one end and retrieves the infrared radiation but allows the millimeter wave radiatin to pass. Cassegrainian optics are positioned adjacent the other end of the tubular member for directing incoming millimeter and infrared energy into the guide. Subsequently, the energy impinges on the beam directing lens means that separates the respective energies, dividing them into two separate and distinct paths.

Abstract: A circularly polarized microstrip antenna for microwaves has a two layer substrate with a first layer of dielectric material spaced above the ground plate by an air gap comprising the second layer of the substrate, so arranged that the effective dielectric constant of the substrate in the range of 1.25 to 1.4 (for an infinite ground plane) and 1.25 to 1.6 (for a finite ground plate).The preferred values of the effective dielectric constant are respectively 1.3 and 1.5 for the infinite and finite ground plane forms of the antenna.

Abstract: Antenna apparatus for use in introducing electromagnetic energy into subsurface earth formations and acquiring measurements relating to propagation of such energy therethrough. Antenna construction includes a resonant cavity-backed slot, the cavity being filled with a fluid. The slot receives an insulator plug serving as a floating piston whereby pressure differentials between the cavity and the surrounding borehole are accommodated. A metallic strap within the cavity grounded at one end to the tool body interconnects at the other end to a matching and tuning feed network. A lumped element resonant circuit behind the slot is thereby formed for either radiating or receiving transmitted or received electromagnetic energy, respectively.

Abstract: A shield for a satellite earth station located in a dense radio frequency environment. The shield includes a satellite earth station antenna position in a pit. Surrounding the pit is a tear-shaped earthen berm. Positioned on top of the berm is a wall made of a series of modular precast concrete panels specially designed to reduce the diffraction of radio frequency interference over the top of the panels and to minimize the internal reflection of radio frequency interference. The panels each include an inner face of two sets of horizontal slats set at alternating angles. The two sets of slats are designed to attenuate and disperse radio frequency interference in the range of the satellite communication downlink and uplink frequencies. In addition, the present invention includes specially shaped grooves cast into the top face of the panels which attenuate radio frequency interference passing over the top of the wall.

Abstract: There is disclosed a tag adapted to be attached to merchandise and the like to deter theft of the merchandise. The tag includes an electronically-detectable device and a frangible container to provide a telltale stain on the merchandise to show attempted unauthorized removal of the tag.

Abstract: A monopole antenna is mounted on a ground plane and incorporates a radiating structure in the form of a blade perpendicular to the ground plane, for loading the antenna. An elevated feed is formed by a biconical central post between the blade and the ground plane. Tuning is also accomplished by a capacitive strips spanning the biconical central post and by outboard inductive posts which connect between the ground plane and the blade to provide shunt inductance. Alternatively, additional tuning may be accomplished by a circuit between upper and lower portions of the central post.

Abstract: A circularly polarized microwave radio antenna which is constructed so that its phase center can be very easily and very accurately positioned with respect to a marker point over which the antenna is placed is disclosed. The antenna includes a ground plane, antenna elements in a common plane parallel thereto and supported by a perpendicular center post, separate feed lines for each element and a combining network all positioned symmetrically about an axial bore in the center post so that the phase center of the antenna is on the axis of the center post at the intersection with the upper surface of the ground plane. A graduated rod may be positioned in the bore to align the antenna with the marker point.

Abstract: A double grid reflector antenna for radiating different signals having pure linear orthogonal polarization comprises a couple of identical and superposed reflecting grids. One of said grids has been rotated its boresight to disengage its focus from that of the other, and feeds are set in the focal plane of the respective grids. The front grid reflects indifferently either horizontal or vertical polarization, while transmitting the orthogonal polarization to be reflected by the rear grid.

Abstract: Plastic-made parabola antennas are improved to get more wave gain in the process of manufacture thereof where a wave reflector material is embedded in other molding materials so as not to cause dislocation thereof during thermoset-molding.

Abstract: A plural band telescopic antenna, including an added band much higher than the frequencies of the AM/FM band, is realized by making one telescopic section into a center-fed, high frequency antenna and using its coaxial cable feed line for also coupling mechanical extension and retraction forces to that section.

Abstract: A parallel plate waveguide microwave antenna is presented in which transmission or reception of microwave energy is effected by radiating waveguide slots or apertures in a metallized glass plate or plate of other rigid dielectric material. The metallized glass plate cooperates with another metallized glass plate or other rigid dielectric material or a metal plate to define a parallel plate waveguide with air or an inert gas or vacuum as the dielectric between the plates. When used as a transmitter antenna, a central electrode propagates waves in the dielectric medium in expanding circles; and the slots or apertures in the metal layer act as scattering sites to couple the waves to free space. When used as a receiver antenna, the reverse will occur.

Abstract: An arrangement for a vehicle- or vessel-borne surveillance apparatus is provided with a two-axis, vehicle- or vessel-borne gimbal system (2, 3) and a platform (4) suspended by said gimbal system (2, 3). The platform (4) can be stabilized about the orthogonal axes (AA', BB') of the gimbal system (2,3) with respect to an earth-fixed reference position. The surveillance apparatus (5) is mounted rotatably about an axis (6) perpendicular to the platform (4). The arrangement comprises two linear actuators (7), being mounted directly on the vehicle or vessel, but acting on the platform (4), to permit the above platform stabilization through a mutually equidirectional or opposite motion. The arrangement further comprises a mechanical, universal coupling to transmit the rotational motion produced by a drive mechanism (8), being mounted directly on the vehicle or vessel, to the surveillance apparatus (5).

Abstract: An antenna apparatus including a small loop antenna element fabricated by printed circuit method, a variable capacitor for matching the antenna element to broadcasting frequency and an amplifier for the received signal. The variable capacitor and the amplifier are mounted on a printed circuit board containing the loop antenna element and the variable capacitor is rotatably mounted on the board centrally of the loop antenna element. A second loop antenna element may be mounted either concentrically on the said side of the printed circuit board or on the other side of the board. A second variable capacitor cooperates with the second antenna element and a single manual element controls both capacitors.

Abstract: An improved latch assembly which operates with a phased array radar antenna to fixedly retain the radar antenna in any one of several predetermined positions. The latch assembly comprises an elongated body member having a leading end section tapered to interfit into the detent means without jamming, a wedging member having a tapered wedge-like configuration which slidably interfits with the gradually tapered ledge of the body member, and a controllable spring-loaded actuating means operable to move the elongated body member and the wedge member into locking engagement with a predetermined detent and then to move the wedging member an additional small distance toward the predetermined detent, this causes the wedging member to be forced laterally an amount sufficient to contact the sides of the housing to effect a controlled wedging of the latch assembly in the housing to prevent any rotation of the radar antenna because of undesired clearances between the elongated body member and the housing.

Abstract: Antenna output for a planar antenna comprising an array of receiving elements provided by two networks (20, 30) of high frequency transmission lines and three sheets (10, 40, 50). The first sheet (10) comprises first cavities (11), the first and second transmission line networks are planar, located respectively on either side of this first sheet and, for signal reception, coupled to each of the cavities by a corresponding number of distinct ends forming exciting probes along two perpendicular axes. The third and second sheets (40, 50) are located on the other side of both of these networks and comprise second and third cavities (41, 51) which are in line with the first cavities. The third cavities are short-circuited in a plane parallel to the surfaces of the sheets, and these sheets are made of a metal or of a dielectric material having metal-plated walls of the cavities.

Abstract: Impedance matching between two conductor transmission lines and conventional antenna designs including a straight antenna element having an effective length of at least one-quarter wavelength in the operating frequency range and a zero impedance at one end is disclosed in which a straight coupling conductor having a length of about one-quarter wavelength in the operating frequency range is mounted in close spaced co-planar relation to such antenna element with one end electrically connected to the zero impedance end of the antenna element. The two conductors of the transmission line are coupled to the antenna element and coupling conductor, respectively, at the interconnected ends thereof and the spacing between the antenna element and the coupling conductor is adjusted along their coextensive lengths to achieve an impedance match at each frequency in the operating frequency range.

Abstract: An antenna mount for aiming a parabolic antenna towards a geosynchronous satellite characterized by four, pivotal sub-assemblies, each of which is rotatable around its own axis. The mount can be quickly adjusted to point the antenna at a particular geosynchronous satellite, or may be caused to sweep across the satellite belt in a scanning manner. The antenna mount can be attached to a support post of virtually any orientation ranging from vertical to horizontal.

Abstract: A compact, lightweight, printed circuit card antenna which is adaptable to a wide range of frequencies, including very low frequencies. The antenna includes a three-dimensional inductor formed on the card, a peripheral conductor stripe on one side of the card which provides a distributed capacitance to the end of the antenna (to cancel inductive effects and broaden its bandwidth), and a peripheral conductor on the opposite side of the card which provides a capacitance to ground (to tune the antenna to frequency), and a transmission line feed point which provides an impedance match to the associated printed circuit flat cable transmission line without the use of impedance matching circuits.

Abstract: Separate receive and transmit interleaved arrays are distributed throughout a defined area. Each array is interconnected, at opposite ends thereof, to a feed line so that the receive and transmit antennas are each associated with four beams. Feed through connections are employed between receive feed lines and the receive arrays of the antenna thereby permitting the utilization of a microstrip structure.

Abstract: A mechanically positioned phase steered transfer lens which is illuminated y a fixed collimation lens. Wide angle scan is accomplished by tilting the movable lens and electronically scanning the beam to the desired angle. The mechanical motion minimizes the required electronic scan angles, thus minimizing the number of phase shifters required.