Abstract: A antenna system of the present invention comprises a radiator for radiating a radio frequency, which is converted from electric power, and which has a impedance matching unit and a power divider; a first reflector for reflecting and filtering the radio frequency; and at least one second reflector for filtering the radio frequency radiated in the sideward direction of the antenna system, which is vertically attached to the first reflector, and is able to be moved in a horizontal direction.

Abstract: A corner reflector antenna array capable of being driven by a coaxial feed line is disclosed herein. The antenna array comprises a substantially right-angle corner reflector having first and second reflecting surfaces. A dielectric substrate is positioned adjacent the first reflective surface, and defines first and second opposing substrate surfaces. In the preferred implementation the dielectric substrate is oriented substantially parallel to, but spaced from, the second reflective surface. The antenna array further includes a plurality of dipole elements, each of the dipole elements including a first half dipole disposed on the first substrate surface and a second half dipole disposed on the second substrate surface. A twin line interconnection network, disposed on both the first and second substrate surfaces, carries signal energy to and from the plurality of dipole elements.

Abstract: Microwave devices incorporate at least one photosensitive baffle that is selectively illuminated, changing the baffle's electronic characteristic from being transparent to microwave energy to being reflective thereof. That action selectively alters an electronic characteristic of the microwave device. The effect is shown applied in a number of devices, including a back lobe antenna. Undesired back lobes occuring at a principal frequency are reduced in a back plane antenna by alternately coupling and decoupling an extension to the antenna's back plane at a rate sufficiently high enough to shift the back lobes to adjacent frequencies. A photoelectrically controlled baffle suitably serves as the extension.

Abstract: A stacked, shorted double C-patch antenna (100) has gap-coupled parasitic elements (102a, 106a, 102b, 106b) and one directly fed antenna element (104a). A second fed element (104b) is conductively fed from the directly fed element. The antenna has a truncated ground plane (108) and a bandwidth that is equal to or greater than approximately 70 MHz at a frequency of approximately 850 MHz. The directly fed antenna element is conductively coupled to a transmitter and to a receiver of a communications device, such as a cellular telephone.

Abstract: An antenna for use in urban areas and the like, wherein the antenna is of a design that can be attached to the exterior corner of a building. The antenna is designed to be a low-profile configuration and conformal so as to maximize the aesthetic quality. The antenna also has a continuous backplane so as to create a radiation pattern that will allow substantially complete coverage of an intersection that is adjacent to the location of the antenna.

Abstract: A horizontally polarized antenna array having extended E-plane beam width, and a method for accomplishing beam width extension. In one embodiment of the invention, an antenna array is provided that comprises a driven dipole element mounted to a conductive means forming a ground plane, the driven dipole element having opposing arms, and a pair of collinear parasitic dipole elements disposed on opposite sides of the driven dipole element, the parasitic dipole elements having opposing arms inclined toward the ground plane such that the opposing arms of each parasitic dipole element are perpendicular to one another.

Abstract: A wide bandwidth, shorted, dual C-patch antenna includes a truncated ground plane, a layer of dielectric material having a first surface overlying the ground plane and an opposing second surface, and an electrically conductive layer overlying the second opposing surface of the dielectric layer. The electrically conductive layer is differentiated into a plurality of antenna elements including a driven antenna element and at least one non-driven, parasitic antenna element. Each of the antenna elements is in the shape of a parallelogram and has one of a rectangular and a non-rectangular (e.g., parabolic, triangular, pentagonal) aperture having a length that extends along a first edge of the electrically conductive layer and a width that extends towards an oppositely disposed second edge. The length has a value that is equal to approximately 20% to approximately 35% of a length of the first edge.

Abstract: A driven element is disposed on an antenna axis for transmission of electromagnetic energy in a transmission direction along the antenna axis. First and second parasitic arrays are disposed on opposite sides of the antenna axis in the transmission direction from the driven element. At least a portion of the antenna axis adjacent to the parasitic arrays is without parasitic elements. Each parasitic array has a plurality of parallel parasitic elements or directors spaced apart along a respective array line that includes a proximal portion adjacent to the driven element that extends in a general direction that is at an acute angle to the transmission direction. The first and second parasitic arrays are sufficiently close to the antenna axis to produce a radiation pattern that has a lobe with greatest magnitude in the transmission direction.

Abstract: An antenna system includes a first antenna positioned on a first device housing and a parasitic radiator positioned on a second device housing. The housings move relative to one another to collapse the device during a standby mode and extend the device during an active communication mode. The first antenna and the parasitic radiator are positioned on their respective housings such that they are parasitically coupled when the housings are collapsed and are not coupled when the housings are extended.

Abstract: A layered antenna is disclosed having at least one radiating element comprising a pair of colinear probes together forming a dipole and a distribution network therefor formed as a single printed conductive pattern layer, a separate metallic layer spaced at a uniform distance from said conductive pattern layer, the metallic layer acting as a ground plane for the distribution network only and further shaped to form a pair of substantially identical parasitic radiating elements for the probes of each radiating element dipole.

Abstract: The disclosure relates to broadcasting by means of rotary antennas using rigid dipoles. Each of two distinct channels passes through the joint between the fixed support of the mobile part of the antenna and rise vertically into the interior of the mast to respectively reach two distinct vertical groups of dipoles. It is thus possible to carry out two simultaneous transmissions from one and the same rotary antenna. Application to broadcasting in decameter waves.

Abstract: A television broadcast invention comprising an elongated vertical support, a plurality of transmission lines extending upwardly along the vertical support, a plurality of primary radiators spaced along the length of the vertical support and connected to the transmission lines for radiating vertically polarized signals, and a plurality of parasitic radiating elements disposed radially outwardly from the primary radiators for re-radiating the vertically polarized signals as elliptically polarized signals. The primary radiators are preferably open-sleeve dipoles mounted on and surrounding a central hollow mast and fed by transmission lines extending along the hollow interior of the mast.

Abstract: A tubular mast has a tubular boom detachably mounted thereon, and a plurality of tubular antenna elements are detachably mounted on the boom. An elastic cord is disposed within and is connected to the boom. A further elastic cord is disposed within and is connected to the mast. Additional elastic cords are disposed within and are connected to the antenna elements. The elastic cords disposed within the mast and the antenna elements are slidably connected to the cord portion disposed within the boom. The elastic cords maintain the components in operative position and allow the components to be detached from one another to fold the antenna into collapsed position.

Abstract: A multiple-frequency monopole or dipole antenna or antenna element that exhibits resonance at multiple arbitrary predetermined frequencies at a single feedpoint includes a driven conductor operative on a first arbitrary predetermined frequency and including a feedpoint. A number n of additional non-driven conductors, wherein n is at least one, resonant at respective n arbitrary predetermined frequencies different from the first frequency are disposed in substantially parallel spaced relationship at a predetermined spacing to electromagnetically couple the driven and non-driven conductors and produce a non-reactive impedance at the feedpoint at the first and at each n additional frequency. Preferably, the predetermined spacing of the driven and non-driven conductors is determined according to the equation: ##EQU1## where d.sub.

Abstract: A dual band signal receiver is provided with relatively coaxial antenna assemblies electromagnetically coupled to respective upper and lower band rectangular waveguides and ports through suitable polarization switching assemblies. The upper band rotatable antenna assembly consists of a dipole feed having driven dipole elements, parasitic dipole elements and a corner reflector element electromagnetically coupled to the upper band rectangular waveguide by a suitable transmission line extending substantially along the longitudinal axis or centerline of the lower band cylindrical waveguide.

Abstract: Disclosed is an array antenna (10) that may be reconfigured to point in multiple directions. The array antenna includes a driven element (12) coupled to a transmission line (14) and a pair of passive elements (22) and (24). The passive elements (22) and (24) each include three antenna segments that are coupled together by a pair of optoelectronic switches (26) and (28), respectively. When the optoelectronic switches coupled to a particular passive element are closed the element functions as a reflector; when the switches are open, the element functions as a director. Other reconfigurable antennas are also disclosed, including antennas with reconfigurable gain and field pattern characteristics.

Abstract: There is provided a new and useful field adjustable sectoral antenna comprising a flat reflecting surface having a front surface and first and second sides; at least one radiating element mounted in front of the front surface; and a pair of side panels each having front and rear edges and inner and outer surfaces; and wherein the panels are mounted with their inner surfaces along respective ones of the first and second sides of the reflecting surface for forward and rearward sliding movement of the side panels relative to the reflecting surface.

Abstract: A planar dipole antenna is arranged on a non-conductive substrate having an exposed, planar surface. The antenna includes a first quarter wavelength element having a first end and an opposite second end and a second quarter wavelength element having a third end and an opposite fourth end. The first, second, third and fourth ends, respectively, are arranged on a common straight line with the second and third ends adjacent to each other. A third quarter wavelength element, having a fifth end and an opposite sixth end, is arranged adjacent to the first element with its fifth end adjacent to the first end of the first element and its sixth end both adjacent to and physically connected with the third end of the second element. A signal source or sink is coupled to the first end of the first element and the fifth end of the third element, respectively, for providing electrical energy to, and/or receiving electrical energy from the antenna.

Abstract: Wideband antenna systems may provide continuous coverage over the VLF, HF, VHF, and UHF frequency ranges. Matching transformers, insertion resistors and damping elements are integral parts of these antenna systems.

Abstract: This Yagi-Uda-type antenna includes also a sleeve embracing the dipole. The sleeve may be a closed cylindrical element surrounding the dipole or it may comprise a pair of discrete elements forming an "open sleeve". The dipole, sleeve, reflector, and director elements may be in filamentary form, or they may be fabricated from stripline.

Abstract: A miniature microstrip dipole antenna is constructed on a high permitivity dielectric substrate for compactibility with microwave monolithic integrated circuit (MMIC) technology. The antenna comprises two dipole arms coupled to opposite faces of the substrate. The dipole arms are coupled to a microstrip transmission line through a tapered balun. The tapered balun comprises two conductors on opposite faces of the substrate which are coupled to corresponding dipole arms. The conductors are separated laterally (with respect to the width of the face of the substrate) a calculated distance, and are gradually tapered. This allows the balun to efficiently transform unbalanced signals at the microstrip transmission line to balanced signals at the plurality of dipole arms. Alternatively, the balun allows balanced signals at the dipole arms to be efficiently transformed to unbalanced signals at the microstrip transmission line.

Abstract: A radiating element comprises a groundplane, a dielectric layer and a conductive pattern comprising a folded dipole (20, 21), a feed line (18, 19) for the dipole and a plurality of closely spaced directors (22), all lying in a common plane parallel to the ground plane. An array of such elements with a suitable feed network provides a flat antenna with a squinted beam. The squint angle can be adjusted by adjusting the phase delay between columns of elements. The beam can be steered by selection of the appropriate squint angle and by rotationally adjusting the antenna in its own plane. The antenna is suitable as a less obtrusive alternative to a dish antenna.

Abstract: A dipole feed for a paraboloidal reflector antenna uses a conical reflector to direct the radiation of the dipole towards the concave reflecting surface of the parabola. The size and apex angle of the conical reflector are optimized to yield the desired feed pattern, the optimization parameters depending on the reflector size and focal length and being obtained numerically or experimentally to maximize reflector gain.

Abstract: A dipole antenna system includes a driven dipole element and two parallel parasitic dipole elements equally spaced from the driven dipole element. Dual polarization can also be achieved by using two such systems arranged orthogonally.

Abstract: Antenna for operation on a plurality of frequencies, the antenna including apex fed opposing swept elements and a plurality of stubs parallel to a central element, a plurality of capacitors connected between one end of the central element and ends of the stubs, and a coaxial cable connected to the opposing swept elements. Each swept element has a triangular configuration with a central element running from the apex to the base of the triangle at a perpendicular intersection. Plural matching stubs connect from the coaxial fed apex and parallel along the central tube, secured at the other end with clamps or capacitors. Ceramic doorknob capacitors connect between the coaxial fed apex and a free end of the first stub and between the first and second stub ends. A hairpin coil can be utilized between the apex fed and the first capacitor. A matching end can connect across the feed point at a common matching stub point for the swept elements.

Abstract: In general a coaxial feeder connected directly into the center of a half-wave dipole antenna disturbs electrical balance and therefore reduces the effectiveness of the screen of the feeder. In the present invention a dipole with two quarter-wavelength elements symmetrically connected through respective identical capacitors to the screen of the feeder is fed through an inductor connected to the junction between one element and its capacitor. By having equal reactances, the capacitors balance the dipole to earth and by means of its phase delay the inductor restores a resistive impedance termination for the feeder.

Abstract: To provide broad bandwidth in a multiple-band directional antenna, the antenna includes an array of parallel horizontal elements, which are: (1) an open-sleeve dipole as the driven element; (2) a trap director element; and (3) trap reflector elements. The driven element includes: (1) a trap central dipole which is center-fed and has sections self-resonant within the bands of 21.0 to 21.45 megahertz and 14.0 to 14.35 megahertz; and (2) two unequal-length sleeves self-resonant at 28.0 to 29.7 megahertz. The director and reflector elements are resonant in the same bands and are spaced and tuned for directivity of the array.

Abstract: Antenna for operation on a plurality of frequencies, the antenna including apex fed opposing swept elements and a plurality of stubs parallel to a central element, a plurality of capacitors connected between one end of the central element and ends of the stubs, and a coaxial cable connected to the opposing swept elements. Each swept element is of a triangular configuration with a central element running from the apex to the base of the triangle at a substantially perpendicular intersection. A plurality of matching stubs connect from the coaxial fed apex and substantially parallel along the central tube, secured at the other end with clamps or capacitors. Ceramic doorknob capacitors connect between the coaxial fed apex and a free end of the first stub and between the first and second stub ends. A hairpin coil can be utilized between the apex feed and the first capacitor, providing required circuit Q. A matching end can connect across the feedpoint at a common matching stub point for the swept elements.

Abstract: A microwave radiator comprises a generally cup-shaped, at least partly metallic cavity with a cylindrical wall and an open end which is bounded by an edge or rim with two diametrically opposite axial projections, in the form of acute-angled cusps or rectangular teeth, which are bisected by an axial plane perpendicular to a dipole disposed inside the cavity. The open cavity end may be covered by a dielectric radome of frustoconical or stepped cylindrical configuration.

Abstract: A zigzag antenna for broadcasting circularly polarized electromagnetic energy at a mean wavelength L. The zigzag antenna includes a zigzag shaped radiating element (10, 12) composed of plural essentially linear segments (20). These segments, each L/4 in length, are disposed end-to-end with each segment being at right angles to adjacent segments. L/2 non-radiating delay lines (22) are interposed between adjacent segments at alternate junctions between the segments, with the segments being directly joined at the remaining junctions. When fed with electromagnetic energy, the element will broadcast circularly polarized waves since each pair of adjacent segments are orthogonal in space and phase. In the described antenna embodiment, two radiators (10, 12) are arranged above a reflecting panel (16), and are fed from a central feed point (14).

Abstract: A UHF antenna for black and white and color television receivers embodies a dished reflector and coacting a dipole mounted a fraction of a wave-length in front of the reflector and being of bow tie configuration. The antenna possesses broad band characteristics for wide angle reception, and wide frequency deviation at UHF wave-lengths. The antenna structure which is for indoor use is fabricated from simple sheet metal components and embodies an integral support base which can be manually adjusted in any direction. Economy and simplicity of construction are featured.

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: This invention comprises an antenna array of collinear, end-fed dipoles spaced substantially less than one-quarter wavelength from the reflector. Consecutive dipoles are energized through phasing loops with the end dipole energized by a coaxial feeder or by one of the two output ports of a balun. A radome with a helically wound resistance heating wire is used to protect the array from the elements. Means comprising the addition of small auxiliary radiators at one of the ends of each dipoles are provided to reduce radiation polarized perpendicular to the axis of the array.

Abstract: A dipole antenna adjustable in span and distance to the reflector provides higher gain reception for a television receiver. By maintaining the ratio of span to distance constant optimum tuning is possible over a given band of frequencies. Tuning adjustment control is obtained from behind the reflector to eliminate interference with the radiation pattern of the antenna. BACKGROUND OF THE INVENTIONThe present invention relates to tunable communication antennas and more specifically to a directional antenna tunable over the UHF band of television frequencies.More and more in recent times VHF channels for television broadcasting in many areas of the country has become limited and the need has greatly increased for UHF channel utilization. Broadcasting in the UHF band, however, presents the problem of greater transmission path loss and higher gain antenna systems are required.

Abstract: Tactical radio navigation systems provide bearing information to an interrogating aircraft in response to pairs of interrogation pulses received at a beacon transponder, the system also provides distance measuring and identification information. To provide the required bearing information, pulses radiated from the central antenna array are modulated at a 15 Hz frequency and by 135 Hz frequency, by parasitic elements rotating around a stationary central array. Broadband operation of the system is provided by a distribution pattern of the 135 Hz parasitic elements mounted radially from the central antenna array on a dielectric disc. Nine groups of radially displaced 135 Hz elements are circumferentially arranged around the dielectric disc and each element of a group is tailored to a particular frequency band in the frequency spectrum allotted to radio navigation systems.