Abstract: A dipole antenna consisting of a number of sub-elements, each sub-element comprising a plurality of thin electric conductors or strips of wires arranged on the surface of an insulating cylinder. The conductors in each sub-element have the same length and are distributed around the circumference of the cylinder, so that each such sub-element forms a so-called "thick" dipole element. The lengths of the conductors in different sub-elements are different, so that the sub-elements together will cover a broad frequency band. At least each conductor in the group having the longest conductors are provided with inductive reactances, to prevent excitation of said longer conductors in higher modes at resonance frequencies of the shorter conductors.

Abstract: Circularly polarized microstrip antennas consisting of thin electrically ducting, square-shaped radiating elements formed on one surface of a dielectric substrate and having a ground plane on the opposite surface of the substrate. Two feed points are used to provide a circular polarized radiation pattern. The feed points are located along the centerlines of the antenna length and width or along the diagonal lines of the element and the input impedances can be varied by moving the feed points along both centerlines or both diagonal lines from the centerpoint of the element. The antennas can be notched in from the edges of the radiating element along the centerlines of the element width and length, or along opposite diagonal lines of the element, to the optimum input impedance match feed point.

Abstract: Circularly polarized microstrip antennas consisting of thin electrically ducting, square-shaped radiating elements formed on one surface of a dielectric substrate and having a ground plane on the opposite surface of the substrate. Two feed points are used to provide a circular polarized radiation pattern. The feed points are located along the centerlines of the antenna length and width or along the diagonal lines of the element and the input impedances can be varied by moving the feed points along both centerlines or both diagonal lines from the centerpoint of the element. The antennas can be notched in from the edges of the radiating element along the centerlines of the element width and length, or along opposite diagonal lines of the element, to the optimum input impedance match feed point.

Abstract: A waveguide bandstop filter is described. Two ceramic dielectric disc resonators each having a resonant frequency f.sub.0 and separated by 3/4.lambda.go, where .lambda.go is the wavelength at f.sub.0, are each disposed in individual apertures in the waveguide wall. The substantial portion of each resonator is exterior to the waveguide cavity and surrounded by a metallic housing which isolates each resonator from each other. The resonators are oriented so that a coupling arrangement exists between the electromagnetic energy propagating through the waveguide and each resonator so that a resonant mode is excited therein at frequency f.sub.0.

Abstract: A miniature radio antenna formed integral with a molded plastic housing comprising a body 1 and a cover 2. The antenna 1', 1", 2', 2" includes sheets, foils or films of electrically conductive metal or coats of conductive paint laid on the inside surfaces of the opposing housing sections, or conductors embedded therein. The antenna is free from adverse acoustic effects due to resonant vibrations in sympathy with a speaker mounted in the housing, and the housing may be molded into any desirable external shape, including fully rounded corners, without increasing the size.

Abstract: An antenna system for producing from a fixed array of active antenna elements which are each omnidirectional in a plane, a sensitivity pattern that is directional in said plane and which pattern can be rotated around the array. The system consists of at least three antenna elements located at the corners of a regular polygon and are excited with substantially equal magnitudes of current that are in the same phase at two adjacent corners and different in phase by substantially 90 electrical degrees at the third corner. The antenna system further includes an electrical power dividing and phasing network as well as electrical switching means to effect proper rotation.

Abstract: An endfire-type phased array antenna comprises n antenna elements (n.gtoreq.3). The difference of current flowing through the antenna elements is controlled to one which is pre-determined by adjusting each length of the feeders and by coupling the phase inverting circuits to alternate antenna elements. The current amplitude ratio thereof is also controlled to a pre-determined value by using a mixing or distributing circuit. Thus an antenna having a high directivity in front and no radiation in other directions is provided which can be effectively used for preventing multi-path interference in TV or FM.

Abstract: A radio frequency array antenna system wherein an array of antenna elements in a multibeam array antenna is coupled to one of a pair of beam forming networks and a portion of such antenna elements is coupled to another one of the pair of beam forming networks. Radio frequency amplifiers are coupled between the array of antenna elements and the pair of beam forming networks. The beam forming network which is coupled to only a portion of the antenna elements is used in the transmission of continuous wave radio frequency energy and the other beam forming network is used in the transmission of pulsed radio frequency energy. During transmission of the continuous wave energy only the portion of the radio frequency amplifiers coupled to the corresponding beam forming network is powered and during transmission of pulse modulated radio frequency energy all of the radio frequency amplifiers are supplied with power.

Abstract: A four port directional coupler using two substantially identical transformers, each transformer having a turn ratio N with a substantially pure resistive impedance across both of the transformer's secondary windings and a substantially pure resistive impedance connecting the transformer's primary windings, whereby the coupling coefficient, C, of the directional coupler is a function of the said resistive impedances and N and is substantially a continuous function of the values of said resistive impedances for any independently selected value of N.

Abstract: An extendable half-wave dipole is capacitively coupled to a driven resonant helical antenna for use as on a hand-held, two-way portable radio, the helix being end fed. The dipole may be mounted adjacent to or collinear with the axis of the helix. The collinear mounting requires non-conductive portions on each end of the dipole. Optimum dimensional and performance characteristics are available without switching.

Abstract: An electrical branching filter which includes two dielectric filters each containing, in a casing of metallic material, exciting means, exciting rod member and at least one dielectric resonator disposed between said exciting means and said exciting rod member, while the exciting rod members of the two dielectric filters are connected to each other through connecting means so as to form coupling means, with input and output connectors being respectively connected to a junction between said exciting rod members and to one end of each of said exciting means.

Abstract: An omnidirectional broad band antenna employs a slot and a pair of radiating arms excited by the slot. In one embodiment slots are formed in a coaxial transmission line and covered by a resin bonded filament wound glass fiber tube which serves as an integral radome and permits pressurization. The arms are of substantial girth and arc upwardly, downwardly respectively and circularly, one clockwise and the other counterclockwise thus providing a large spacing between arms. The antenna is characterized by a broad bandwidth and low VSWR.

Abstract: A multi-director parasitic array attached at the center of a microstrip anna design to provide a simple, low cost, efficient feed.

Abstract: An extensible antenna assembly defined by a strip wound into a coil and extensible out of the coil through a guide for forming the strip into an elongated tubular length. In two embodiments the strip is made of a metal whereby the tubular length establishes the antenna for radiating and receiving radio frequency energy and the coiled or wound coil portion defines a coil integrally coupled and electrically continuous with the tubular portion to define a variable inductive reactance for automatically maintaining the antenna resonant to a predetermined frequency in correlation with and responsive to the extended position of the antenna. An insulating means, comprising a strip in the first embodiment and a conical spindle in the second embodiment, insulates the turns of the strip defining the coil and is configured to change the inductance of the coil non-linearly in response to linear movement of the antenna.

Abstract: A radio antenna which can be readily tuned to the exact frequency of operation, easily coupled to a coaxial feed-line with minimum standing wave ratio and/or which is normally vertical and can be used where horizontal space is at a premium, such as: indoors or on boats. The antenna has a center loading coil, the inductance of which is adjusted by means of a split coaxial sleeve axially moveable relative to the coil. The input impedance of the antenna is adjusted relative to the impedance of the feed-line by means of a coupling transformer, the transformation ratio of which is controlled by means of a coaxial split metal sleeve axially adjustable relative thereto. A coaxial cable wound into a coil around a ferrite core attenuates the high ratio frequency voltage on the end of the antenna to the feed-line. For indoor use, the antenna is housed in an extensible tubular housing which can be extended to engage the ceiling and floor of a room to hold the antenna in vertical position.

Abstract: An antenna for use in propagating or receiving microwave radiation having both left-hand and right-hand circular polarization. The left-hand and right-hand circularly polarized radiation may be transmitted or received simultaneously without interference with one another, that is, they are isolated from one another by 27 dB or more. The preferred antenna comprises an array of closely clustered waveguide elements each of which converts respective linearly polarized signals to left-hand and right-hand circularly polarized signals and vice versa. Isolation means also are provided in each of the waveguide elements for preventing radiation either propagated or received by a waveguide element from being coupled into the radiation being propagated or received by other waveguide elements in the array. Preferably, square waveguide is utilized for the array elements and the isolation is provided by a plurality of conductive elements mounted on each of the open ends of the waveguide elements.

Abstract: A tunable electrical filter is disclosed wherein an RC (resistor-capacitor) network comprising a plurality of switchable capacitors among the components determining the time constant of the filter provides a given minimum value of filter time constant and, therefore, a given minimum bandwidth, when all the capacitors are continuously connected in the network. Each capacitor is coupled to the network through the output means of an electronic switching means. A pulse generator connected to the input means of said switching means provides a train of pulses having an adjustable ON-time to OFF-time ratio. When all the capacitors are periodically switched by the output of the pulse generator, the effective filter time constant increases from said given minimum value as the ON-time compared with the OFF-time decreases. The pulse generator is provided with control means for adjusting the ON-time to OFF-time ratio.

Abstract: A stripline horizontally polarized dipole and passive director antenna ar, operative at L-band (1220-1280MHz), mounted in a 90.degree. corner reflector constructed of a grid of cylindrical rods which are hinged along its apex permitting folding of the reflector over the antenna array to protect the elements of the array, for example, during transport.

Abstract: An electromechanical filter has a plurality of mechanically coupled mechanical resonators disposed parallel to each other, in particular resonators of the flexural vibration type. The first and last resonators in the direction of transmission are each provided with an electrostrictive transducer element which has a feeder which is constituted, in particular, by an insulating bushing provided in a metallic base plate and is connected with an electrical input or terminal circuit, respectively, constructed as an LC resonant circuit. The capacitor of the input circuit or the terminal circuit is disposed within a trough-shaped recess in the base plate beneath the filter and the capacitors are encapsulated within an insulating material to provide a capacitor unit which fits into the recess in releasable engagement therewith.

Abstract: A bracket assembly for mounting a citizen band (CB) antenna on the hinge bolt of an automobile trunk lid is disclosed. When the trunk lid is closed, only the antenna and one end portion of the bracket assembly is outside of the trunk compartment. In order to completely conceal the antenna without disassembling the bracket assembly from the hinge bolt the trunk lid is lifted and the bracket assembly is pivoted about a first axis and then about a second axis that is preferably perpendicular to the first axis. In this manner the entire bracket assembly as well as the antenna mounted thereon may be stowed and completely concealed within the trunk compartment without disassembling the bracket assembly from the hinge bolt.