Abstract: The present invention provides a metrology antenna system that combines a sleeve dipole antenna having two coaxial input ports with a balancing network. This combination (1) minimizes or eliminates spurious radiation from the balancing network (2) provides for a symmetric pair of feed regions which may be made arbitrarily small, and (3) provides for an essentially perfect impedance match to a broad range of resistive source impedances. The present invention provides a fabrication of arbitrarily small feed regions such that dipoles can be realized at high frequencies at little manufacturing cost.

Abstract: A low loss, compact radio antenna and antenna loading method. For a monople antenna a tubular, conductive radiating element provided whose length is less than one-quarter the wavelength of the nominal frequency of the antenna. A tubular conductive series loading element disposed within the radiating element, the series loading element having a first end for connection to a radio and being electrically connected to the radiating element at a position spaced outwardly from the first end so as to provide inductance in series with the radiating element. An elongate conductive shunt matching element is disposed within the series loading element for electrically connecting the series loading element from a point therein to a mirror image thereof so as to provide shunt inductance that matches the impedance of the antenna to the impedance of a device connected thereto at the nominal frequency.

Abstract: A dipole antenna with a radiating structure comprises at least one device adapted to the conversion of analog signals into digital signals and/or digital signals into analog signals, said device being positioned in a part of the antenna that is insulated from electromagnetic waves or phenomena The antenna can be used in radiocommunications systems.

Abstract: The present invention provides a metrology antenna system that combines a sleeve dipole antenna having two coaxial input ports with a balancing network. This combination (1) minimizes or eliminates spurious radiation from the balancing network (2) provides for a symmetric pair of feed regions which may be made arbitrarily small, and (3) provides for an essentially perfect impedance match to a broad range of resistive source impedances. The present invention provides a fabrication of arbitrarily small feed regions such that dipoles can be realized at high frequencies at little manufacturing cost.

Abstract: Embodiments of a planar antenna suitable for use with a portable device for wireless communications are described. One such embodiment includes a microstrip line coupled to a radiating poise on one side of a circuit board, and a ground plane coupled to a structure on the other side of the circuit board that functions as a coplanar waveguide having an effective length of one quarter-wavelength. A further implementation includes a transformer portion configured and arranged to match the impedance of an RF signal source to the antenna driving impedance.

Abstract: An antenna comprising a center-fed coaxial dipole having a first element, configured as a whip and a second element having a first and second portion for transmitting/receiving in dual frequency bands. The first element, first portion and second portion having a length equal to one-quarter wavelength of the mid-range frequency of the frequency band. The first portion configured as an inner conductive cylindrical sleeve coaxially aligned with the whip. The second portion, an outer conductive cylindrical sleeve, coaxially aligned with inner sleeve. A coaxial conductor having an inner conductor electrically connected to the whip and an outer conductor connected to the second element. A coaxial choke axially aligned with the conductor, having a length of one-quarter wavelength of the mid-range frequency band, a first end of the choke connected to the outer conductor and a second end being spaced from the second element an equivalent distance as the choke length.

Abstract: Disclosed is a portable communication terminal usable at multiple frequencies while being capable of achieving a reduction in specific absorption rate (SAR). The terminal includes two dipole antennas mounted on an antenna printed circuit board (PCB) mounted to a PCB of the terminal and respectively adapted to operate at usable frequencies f1 and f2. A coaxial cable is connected at its end to the dipole antennas, and a cylindrical bazooka type balun (bazooka) for multiple frequencies is fitted around the end of the coaxial cable. The bazooka includes a first dielectric cylinder, a second dielectric cylinder, and a conductor cylinder. The dielectric cylinders are coaxially fitted in the dielectric cylinder. The dielectric cylinders are used for the frequencies f1 and f2 while having electrical lengths corresponding to the frequencies f1 and f2, respectively.

Abstract: An antenna comprising a center-fed coaxial dipole having a first element, configured as a whip and a second element having a first and second portion for transmitting/receiving in dual frequency bands. The first element, first portion and second portion having a length equal to one-quarter wavelength of the mid-range frequency of the frequency band. The first portion configured as an inner conductive cylindrical sleeve coaxially aligned with the whip. The second portion, an outer conductive cylindrical sleeve, coaxially aligned with inner sleeve. A coaxial conductor having an inner conductor electrically connected to the whip and an outer conductor connected to the second element. A coaxial choke axially aligned with the conductor, having a length of one-quarter wavelength of the mid-range frequency band, a first end of the choke connected to the outer conductor and a second end being spaced from the second element an equivalent distance as the choke length.

Abstract: The present invention provides a sleeved dipole antenna for radio wave communications, wherein the antenna includes a lossy material disposed about a coaxial feed line. The lossy material in combination with a lower radiator attenuates noise transmitted to the antenna through a ground.

Abstract: A cylindrical reflector having a through hole in conformity with the shape of an elemental portion is fitted to the elemental portion in a LAN antenna in which the elemental portion encloses a linear conductor therein and projects from a base table, and further, the reflector is turned to be set at a position at which the directivity is formed in a specific direction. A flat plate or a curved plate forming a reflecting surface of the reflector is arbitrarily set, thus forming a desired radiation pattern of a beam.

Abstract: A multiband antenna has a first antenna device for a first frequency band range and at least one second antenna device for a second frequency band range. The first antenna and the at least second antenna are arranged such that they are integrated and interleaved in one another. The associated dipole halves of the antennas are designed to be at least electrically in the form of, or similar to, sleeves or boxes. The dipole halves of the at least two antennas are short-circuited to one another at their respective mutually adjacent end, and extend from there with different lengths depending on the frequency band range to be transmitted. The dipole halves for transmitting the respectively lower frequency band range are located within the dipole halves which are intended for transmitting a respectively higher frequency or a respectively higher frequency band range.

Abstract: The present invention is directed toward a dual linear or circular polarized antenna comprised of two orthogonally linearly polarized radiative elements. More specifically, the present invention is for a slender slot-dipole antenna, where the slot and the dipole are located in the same physical structure. Feed line interference to the antenna can be eliminated by including a centrally located shaft. The antenna of the present invention can be used as either a receive antenna or a transmitting antenna and could be used to form an array. In one embodiment, the antenna is comprised of two substantially cylindrical members, wherein the slot is located on the outer surface of the antenna and the cylindrical members function as dipoles. Other embodiments are directed toward multiple slots and polygonal-shaped antennas.

Abstract: A dual band antenna for a mobile communication system which includes: a metal tube having an open end; a coaxial feed line having inner and outer conductors, with one portion of the coaxial line inserted into the metal tube, a ground plane connected to a portion of the metal tube opposite the open end and to the outer conductor of the coaxial feed line, and, a signal line electrically coupled to the inner conductor and protruding from the metal tube at the open end thereof. Preferably, the dimensions of the metal tube, the coaxial feed line and the signal line are selected such that the antenna is impedance matched to the coaxial feed line over the dual operating band, thereby obviating the need for a separate matching network.

Abstract: An enhanced antenna apparatus suitable for use with portable wireless devices. The antenna of the present invention comprises a conductive sleeve having an inner core that can accommodate one or more signal wires passing therethrough. The conductive sleeve functions as the radiating element of the antenna. The length of the conductive sleeve is made an integer multiple of one half the wavelength of the desired frequency. By passing the signal wires through the conductive sleeve the mutual impedance between the antenna itself and signal wires passing through the antenna is eliminated. Alternatively, the antenna can be constructed on a printed circuit board using elongated printed pattern on the top and bottom layers of the printed circuit board. The length of the printed pattern is made an integer multiple of one half wavelength of the desired frequency.

Abstract: The present invention represents an integrated antenna assembly comprising a cellular communications antenna and a satellite communications antenna. Such an antenna assembly can, therefore, be used for communications over either frequency range. A wireless telephone using this assembly can, therefore, operate with either a terrestrial cellular communications system or a satellite communications system. In a preferred embodiment of the invention, the satellite communications antenna is a quadrifilar helix antenna and the cellular communications antenna is a sleeve dipole. The whip portion of the sleeve dipole is positioned axially in the center of the quadrifilar helix antenna. This orientation permits operation in both the satellite and cellular frequency ranges without significant electromagnetic coupling.

Abstract: A planar sleeve dipole antenna compromises a dielectric substrate with conductive circuits on both sides. Upper circuits include an upper conductive area of the signal feeding microstrip line and its extended conductive area, bottom circuitry includes a lower ground conductor of microstrip line and its two extended conductive areas. Signals are fed from the end of microstrip line, by means of the 1/4 wavelength upper conductive area and the bottom 1/4 wavelength extended conductive area to form a half wavelength oscillating dipole to achieve radiation.

Abstract: A delay line, suitable for use as a feeder stage in an antenna array, comprises a single spiral revolution conductive strip formed on an insulating sheet. In one arrangement, the single spiral revolution conductive strip comprises first to fifth conductive strips connected end-to-end in series. The first and third conductive strips are positioned opposite each other, the third and fifth conductive strips are positioned opposite each other, and the second and fourth conductive strips are positioned opposite each other. The delay line finds particularly advantageous use in a collinear antenna array, particularly due to its very compact size.

Abstract: A narrow and light mobile radio antenna that requires convenient supporting metal fittings provided in a base station is provided. An inner conductor of a coaxial feed line extends upward by a length of ¼ wavelength from the upper end of an outer conductor. This extended inner conductor forms an antenna element. Outside the coaxial feed line, a ¼-wavelength sleeve-like metal pipe made of brass is located with one end connected to the upper end of the outer conductor. On a part of the inner surface of the open end of the metal pipe, an internal thread is formed by tapping. In the open end of the metal pipe, an insulating spacer having an external thread formed around its periphery is inserted. In other words, the insulating spacer is located between the inner wall of the metal pipe and the outer conductor of the coaxial feed line. At the lower end of the coaxial feed line, a coaxial connector for connection with an external circuit is provided.

Abstract: An antenna construction comprises a feed conductor (11, 21) and an antenna element (12, 22, 24, 25, 26, 27) which has a first end and a second end. The feed conductor is substantially electrically unshielded and coupled to the antenna element at a tapping point (13, 23) located between the first end and second end of the antenna element the tapping point dividing the antenna element into two portions having unequal electrical lengths. The antenna element may be a helix (12), a whip (22) or another known two-ended antenna element or a combination of those.

Abstract: An antenna apparatus with a coaxial cable used as a radiation element includes an antenna element having a first electrical length and a feeding point at an end. The coaxial cable is a second electrical length and both the inner and an outer conductors are coupled to a radio wave circuit at corresponding ends. An opposite end of the inner conductor connects to the feeding point of the antenna element. The first and second electrical lengths are selected to have resonance between the antenna element and the coaxial cable so that a radio wave signal is transmitted from both the antenna element and the outer conductor of the coaxial cable. The electrical length may be one quarter wavelength and the coaxial cable can be made of elastic material. Resonance is provided by generating a standing wave along the antenna element and the coaxial outer conductor at one quarter wavelength the desired frequency.

Abstract: An antenna for use with low-band, mid-band and high-band signals, including a coaxial member, a low-band and mid-band signal input connected between one end of the coaxial member outside conductor and the device chassis ground, and a high-band signal input connected between one end of the coaxial member outside conductor and the corresponding end of the coaxial member inside conductor. A first isolation filter adapted to block low-band and mid-band signals from the coaxial member is between the coaxial member and the high-band signal input. A parallel resonant circuit is at the other end of the coaxial member outside conductor and a solid conductor is connected to the parallel resonant circuit and to the other end of the coaxial member inner conductor. The low-band signal input is disconnected from high-band signals by, for example, an RF switch or a second isolation filter between the coaxial member and the low-band signal input.

Abstract: A coaxial dipole antenna element which has omni-directional radiation characteristics in azimuth and can be incorporated into linear antenna arrays to shape the radiation pattern in the vertical dimension is fed by coaxial conductors built into a electrically integral center support extrusion.

Abstract: A dual band antenna for mobile communications includes a rod-shaped radiating element having a first portion of a predetermined length connected to a coaxial feed line, and a second portion of a specified length integrally extended from the first portion. The coaxial feed line connects to a ground plate, and a first capacitive load connects to the first portion of the radiating element. A choke surrounds the second portion of the radiating element, and has a shorting end connected to a distal end of the second portion and an open end at a proximal end of the second portion. A second capacitive load connects to the shorting end of the choke. In a higher operating band of the dual band, the input impedance of the choke is high, such that only the first (lower) portion of the radiating element radiates. At a lower operating band of the dual band, the choke's input impedance is lower to allow for radiation from the entire length of the antenna.

Abstract: An antenna (1) comprises a first elongate antenna element (3) for connection, in use, to a signal carrying element of an apparatus with which the antenna is used, and a shorter second antenna element (5) extending substantially around a proximal end portion (9) of the first antenna element (3), a proximal end (6) of the second element (5) being connected to the proximal end (8) of the first element. A body (12) of a dielectric material is disposed between the first and second antenna elements (3,5). The antenna (1) has at least two optimum operating frequencies, each with an associated usable bandwidth, which bandwidths preferably overlap. The antenna (1) may include further antenna elements (20,22) which further extend the overall usable bandwidth (B.sub.u) of the antenna (1). One or more "ground plane" elements (16,17) are preferably also provided in the antenna for decoupling the first and second antenna elements (3,5) from an earthed screen or element in the apparatus with which the antenna is used.

Abstract: Although conventional antennas have characteristics suitable for mobile radio base stations, their vertical dimension is large, and locations of their installation are limited. A radiator for an first upper antenna 32 is arranged in a hollow nonconductive radome 2, using an internal conductor 7a and a metal pipe 10. A radiator for a second lower antenna 34 is arranged in the radome 2, using metal pipes 14 and 15. Two parasitic elements 31 are installed substantially in parallel with the first antenna 32 below a feeding point 9. Two parasitic elements 33 are installed substantially in parallel with the second antenna 34 above a feeding point 13. These allow the tilt angle to be freely set between -10.degree. and +10.degree. by adjusting the parasitic element length and the antenna to be reduced in size.

Abstract: A system of antennas for conserving space and concealing the separate identity of the individual antennas. The antennas may be a radio antenna and a telecommunications antenna. The antennas may have a common base to eliminate separate wires and holes in the vehicle on which they are mounted. The antennas may be housed within the same casing to protect them from the elements and from other harm.

Abstract: A feed line is coupled to a driven element of an antenna using capacitive coupling elements, such as coupling rods, coupling wires, or conductive tape. The capacitive coupling elements allow signal transfer to or from the radiating element at an optimal transfer point, despite the fact that the optimal transfer point varies with respect to frequency. Conductive extensions may be electrically connected to the capacitive coupling elements to increase the available capacitive coupling. The constant impedance matching system provides a broader frequency response and lower standing wave ratio (SWR) to create a more efficient signal transfer to or from the driven element. A switch may be provided to directly connect and disconnect the capacitive coupling elements from the driven element and allow a choice between the broader frequency response with a flatter SWR curve and a focused frequency response with a sharper SWR curve.

Abstract: A miniature antenna is mounted on a casing of a radio communication equipment such as a portable transmitter/receiver, a pocket telephone, or a mobile telephone of low power type. The miniature antenna is includes a semi-coaxial dielectric resonator and a radiator. The semi-coaxial dielectric resonator has a metal case, a center conductor surrounded by the metal case, and a dielectric material filled between the metal case and the center conductor. The radiator is formed by extending the center conductor approximately the same length as the center conductor and projected from the metal case without contacting the case. A skirt member can be added outside of the semi-coaxial dielectric resonator. According to the above-described structure, the directivity becomes maximum in a horizontal plane and an effect caused by holding the casing with a human hand is decreased.

Abstract: An antenna structure has a rotatable dipole array constituting a driven antenna element, a cup mounted around the dipole, a first conductor connected to and extending from the antenna, and a first dielectric mounted around the first conductor. A second conductor is mounted around the first dielectric, and a second dielectric is mounted around the second conductor. A third conductor is mounted around the second dielectric, and the first and second conductors form a quarter-wavelength transformer. The first dielectric maintains a uniform spacing between the first and second conductors, and the third conductor defines a radio-frequency coupling cavity. The second dielectric electrically enlarges the cavity. Thus the physical dimensions of the structure can be reduced without sacrifice of its electrical properties.

Abstract: A dual frequency vertical antenna for radiating a first and a second airwave signal in response to a first and a second conducted signal, the first airwave signal having a first frequency and the second airwave signal having a second frequency lower than one-half the first frequency. The antenna includes a horizontal base member and a vertical mast, including a coaxially disposed rod, projecting upward from the base member to a masthead. For feeding the conducted signals, a lower mast extension projecting downward from the base member and a tuning sleeve projecting either upward or downward from the base member are tuned to 1/4 wavelength at the first frequency and a single coaxial cable is connected between the base member and a feedpoint on the rod. The first airwave signal radiates from a dipole formed of an 1/4 wavelength upper rod extension extending upward from said masthead and a concentric 1/4 wavelength upper sleeve external to the mast projecting downward from said masthead.

Abstract: A combined AM/FM/cellular telephone antenna system comprises a coaxial cable with an upper portion of the inner conductor of the coaxial cable and an adjacent section of the coaxial cable together forming a cellular telephone dipole antenna. The coaxial cable forms a transmission line connecting the cellular dipole antenna to cellular telephone equipment. The outer conductor of a portion of the coaxial cable below the cellular dipole antenna serves as the AM/FM antenna. The combined antenna is encaged in a fiberglass housing and mounted on a metallic base having an upper shell and a lower shell. The upper shell is electrically connected to the outer conductor of the coaxial cable forming the antenna and the lower shell is connected to a ground plane. A coaxial cable having a center conductor connected to the upper shell and an outer conductor connected to the lower shield provides connection to AM/FM receiver equipment.

Abstract: A flexible dipole antenna comprising a flexible center fed coaxial cable (12) having an insulated center conductor, comprising a second radiating element emerging from a first radiating element connected to the outer conductor of the cable (12) and a basket to attach said antenna to a desired apparatus. The antenna also has a first strain relief member (18) coaxially surrounding said cable where said cable emerges from said first radiating element.

Abstract: In the preferred embodiment of the invention, a broadband dipole antenna 10 for transmitting and receiving electromagnetic energy constructed of coaxially aligned radiating elements 14 and 16 is provided. Each of the radiating elements 14 and 16 has a charge collector 40 and 42 affixed to its free end, that function to collect charges forming a current sink for collecting the current generated by the radiating elements. Coupled with the radiating elements is an isolation choke 44 to isolate the radiating elements against electrical disturbances caused by the antenna support platform 130 and 138 effecting a match of the impedance between the radiating elements and the transmission lives. Another preferred embodiment is a monopole 86 equipped with a charge collector 96. The dipole 10 and monopole 86 are provided pairs of open-sleeves 28 and 26 and 92 and 94 to enhance the instantaneous bandwidth of the radiating elements.

Abstract: A dual function antenna structure transceives in first and second modes. A first feed (120) feeds a primary antenna element (110) for operation in the first mode. A second feed (240) connects to the first feed (120). An upper choke (150) and a metal layer (160) are tuned to a wavelength of the radio frequency energy to be transceived in the second mode. The primary antenna element (110) and the metal layer (160) thus realize a secondary antenna element for operation in the second mode. In a portable radio, dual function operation is thus possible by a compact structure by the first and second feeds (120, 140).

Abstract: A dual frequency vertical antenna for radiating a first and a second airwave signal in response to a first and a second conducted signal, the first airwave signal having a first frequency and the second airwave signal having a second frequency lower than one-half the first frequency. The antenna includes a horizontal base member and a vertical mast, including a coaxially disposed rod, projecting upward from the base member to a masthead. For feeding the conducted signals, a lower mast extension projecting downward from the base member and a tuning sleeve projecting either upward or downward from the base member are tuned to 1/4 wavelength at the first frequency and a single coaxial cable is connected between the base member and a feedpoint on the rod. The first airwave signal radiates from a dipole formed of an 1/4 wavelength upper rod extension extending upward from the masthead and a concentric 1/4 wavelength upper sleeve external to the mast projecting downward from the masthead.

Abstract: An improved coaxial-collinear antenna comprising a pair of continuous inner conductors each having a plurality of dielectric spacers mounted thereon for supporting a plurality of individual outer conductors in coaxial alignment with the continuous inner conductor. The outer conductors are equidistantly spaced along each continuous inner conductor by an amount substantially equal to the length of each outer conductor. The pair of continuous inner conductors are parallel, and the outer conductors mounted on each continuous inner conductor are electrically connected to the other continuous inner conductor between outer conductors consecutively mounted on that other inner conductor.

Abstract: An antenna comprises a feed port, a 1/2 wavelength radiator (20), and a double resonant transformer (10). The feed, port, having a signal feed portion (34) and a ground portion (44), is at a low impedance while the 1/2 wavelength radiator (20) has opposed high impedance ends (21 and 22). For transforming low impedance to high impedance, at two resonant frequencies, the double resonant transformer is coupled between the feed port and the 1/2 wavelength radiator.

Abstract: A dual-band antenna in which EHF signals are connected to one end of a wauide and radiated from the other and wherein a half-dipole for VHF signals is connected to the radiating end of the waveguide and the other half-dipole for VHF is formed by a shield that is coaxial with and surrounds all of the waveguide except the radiating end. VHF signals are coupled to the half-dipole formed by the shield via a matching network.

Abstract: An antenna for a personal communication device designed for reducing RF emissions to a user's head and body comprises a single half-wave dipole antenna element mounted on the top of a telescoping rod such that the antenna element is raised above the user's head when the rod is extended. The rod is completely inactive and serves only to elevate the active antenna element above the user's head and away from the body. A built-in switch is provided which reduces the transmission RF power when the rod is retracted to further protect the user. In a second embodiment, a co-linear array of dipole antenna elements is used. The full array is active for reception. However, a proximity detector senses the proximity of a human body, and lowers the RF transmission power to those antenna elements in the array that are closest to the user's head.

Abstract: An omni-directional, collinear, vertical base station antenna having an adjustable or variable radiation beam tilt capability. Terminations at the drive or feed points are provided by an adjustable, capacitive coupling structure at the feed points between the conductive elements of a feed structure and a radiator assembly for adjusting the physical position of the feed points and thereby the phase of the feed points relative to the upper and lower portions of the antenna to alter the deflection angle of the radiation produced. A signal feed, having first and second conductive feed elements, is connectable to a signal feed line to couple a signal between the feed line and the radiator assembly.

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: An antenna of special form--to wit: a tube and more precisely a tubular dipole--is positioned inside an electrically non-conducting tubular post, typically made of fiberglass, that serves to support an electronic device, typically an irrigation controller, that communicates both by wire and by radio. Wired connection is via wires that are channeled and contained, preferably axially centrally tightly, within the tubular support post. The wires are substantially at radio frequency ground, and serve to connect the irrigation controller to one or more remote electrical devices such as soil moisture sensors and electric valves. The tubular dipole antenna is preferably formed as a fiberglass tube having a conducting exterior surface, normally made of metal and preferably copper, that is divided equally into two tubular segments.

Abstract: An antenna assembly for use with a portable transceiver provides improved communication between the portable transceiver and a base station. A novel antenna assembly is created wherein the radiating portion is elevated above the handset by combining a half wavelength sleeve dipole antenna with a coaxial line section followed by a quarter wavelength choke. Such a configuration reduces the antenna-housing interaction. The quarter wavelength choke prevents the coaxial transmission line from radiating RF energy, and therefore limits the radiation to the sleeve dipole portion of the antenna assembly.

Abstract: A small size helical antenna for radio communication equipment such as a portable transmitter/receiver, a pocket telephone, or a mobile telephone of small power type. The helical antenna is comprised of first and second parallel conductors wound in a coil shape. The second conductor is folded in parallel to the remaining part of the second conductor at some length in accordance with the transmitting/receiving frequency from the top end. The folded part and the upper part of the first conductor form a radiator of the dipole antenna structure and the parallel part of the first and the second conductors form a parallel feeder. The third conductor having the same length as the folded part may be provided on the lower part of the second conductor.

Abstract: An array of collinear coaxial lines utilizes standard size brass tubing with brass rods inserted therein to establish each half-wavelength coaxial section. A coupler positioned between each half-wavelength section has an outer conductor supports and through passages for the inner conductor. Inner conductors of the transmission line elements are soldered to the outer conductors of the respective adjacent transmission line elements so that all elements are excited with the same phase and polarity. Air dielectric between the inner and outer conductors provides a transmission line wavelength equal to that of free space so that the length of each element in the array is a free space half-wavelength long, thereby providing an antenna gain greater than that achievable with transmission lines having solid dielectric supporting the inner conductor.

Abstract: An antenna used for a plurality of frequencies in common according to the present invention has two signal feeding systems for an integrated antenna. The antenna is so constructed that the signal feeding systems are perfectly isolated in DC from each other through a capacitor and at the same time in high frequency, only the signal system for the car telephone frequency band, which is a communication with a moving body, is coupled with the whole antenna, while the signal system for the AM/FM radio frequency band is separated from the antenna radiator portion (radiating element) working at the car telephone frequency band. Owing to a great difference in the frequency between the AM/FM radio frequency band and the car telephone frequency band, no disturbance such as mutual interference, etc. is produced and thus it is possible to obtain stable signal systems separated from each other.

Abstract: An improved bracket is disclosed formed by a tube element (10). Opposing slots (26, 28) are formed into the tube element a predetermined distance from a first end (22) of the tube element. The opposing arcuate sections (30, 32) defined by those slots are deformed by cooperating dies (34, 36) to form the bracket. The tube element (10) can be a tubular antenna (206) secured along an antenna rod (202).

Abstract: An antenna device shared by three different waves has a single two-stage collinear antenna constituted by half-wave dipole antennas which are adapted for a vehicle telephone signal and are stacked one upon the other. The device allows an AM-FM radio receiver to receive AM and FM broadcast signals via a first coaxial cable and a vehicle telephone transceiver to receive a telephone signal via a second coaxial cable. A first impedance converting circuit is implemented as a field effect transistor and connected to the base end of the antenna for matching the antenna and the first coaxial cable in the event of reception of the AM broadcast signal. A second impedance converting circuit matches the antenna and the first coaxial cable at the time of reception of the FM broadcast signal. The impedance converting circuits convert the input/output impedances of the AM and FM signals.

Abstract: A multi-band antenna is adapted to receive signals in the AM/FM bands and to receive and transmit signals in a significantly higher frequency band such as that used for cellular telephone. An AM/FM band antenna is formed of a tubular rod, and a higher frequency band antenna is formed using a centerfed coaxial dipole mounted on top of and coaxially with the AM/FM antenna. The dipole is fed by a coaxial rod attached to a coaxial cable extending through the AM/FM antenna. A cylindrical choke is disposed about the coaxial rod and is spaced a predetermined distance from the dipole antenna to reduce coupling between the AM/FM antenna and the high-frequency antenna. The choke functions to position the input impedance of the high-frequency antenna at the base of the choke in a manner so that a short matching transformer may be used at the base of the choke for connection to the coaxial cable.

Abstract: An omindirectional antenna includes one or more dipole radiators. Each dipole radiator comprises a first and second cylindrical radiating element. Each radiating element includes an end plate for mounting the radiating element coaxially on a tubular mast. The cylindrical radiating elements, end plates and tubular mast are all DC connected. A feed line is provided which may extend through the center of the mast and exit at an opening for connection to a secondary feed line. The secondary feed line is connected to an end of one of the cylindrical radiating elements of each pair of elements for each dipole radiator. The feed line is connected to the end of the cylindrical radiating element opposite the end plate. The configuration of the dipole radiators is such that the radiator functions an an RF choke for the adjacent radiators. An additional single cylindrical element can be provided at the end of a plurality of dipole radiators to provide RF choking for the immediately adjacent dipole radiator.