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: A telecommunication system antenna including: a non-resonating three-wire type folded element which generates an unbalanced mode current and has a matching function; a sleeve element which consists of a conductive sleeve with its one end near the non-resonating three-wire type folded element and a conductive disk in a flange shape around the circumference of the other end of the conductive sleeve, so that the sleeve element radiates electromagnetic waves based on the unbalanced mode current generated by the non-resonating three-wire type folded element; and a coaxial line with its tip end inserted into the conductive sleeve of the sleeve element from the other end of the conductive sleeve so that the coaxial line is electrically connected to the conductive sleeve and to the non-resonating three-wire type folded element.

Abstract: An antenna for mobile communication includes a sleeve antenna having a feed point; at least one linear parasitic element insulated electrically form the sleeve antenna; and a supporting means for supporting the sleeve antenna and the linear parasitic element. The supporting means supports the sleeve antenna and the linear parasitic element so that the feed point of the sleeve antenna is located at a different elevation from an elevation of a central point of the linear parasitic element.

Abstract: A shell structure for a collinear coaxial element array antenna is made of electrical conducting material and includes first and second circular sections separated by a web. The first circular section has an inner diameter that is slightly larger than the diameter of an inner conductor in a coaxial line element of the array antenna, while the second circular section has an inner diameter that is equal to that of an outer conductor of a coaxial transmission line element. The separations of the centers of the first and second circular sections are established by the wed to be equal to the distance between the centers of two adjacent coaxial transmission line elements in the array antenna. The inner conductor of a coaxial transmission line element is inserted in the first circular section and is electrically connected thereto.

Abstract: A monopole radiating blade antenna comprising a driving, high impedance stub mounted to the face of the blade that functions as part of the radiator as well as part of a shunt path between the blade and the base plate. The shunt path is completed by an air coil inductor connected between the center conductor of the stub and the base plate. One embodiment provides the input connector wire and stub in vertical alignment along the center vertical axis of the blade. Another embodiment arranges the stub to be off-set from the input wire. Some advantages over conventional blade antennas include increased gain at low angles of elevation above the horizon, good impedance match over a wide range of frequencies without using conventional 1/4 wave length stub matching that can introduce dielectric losses, low resistance to ground to bleed off static electricity and lightning, non-loading of the high impedance path at design frequencies, and good accommodation of 5/8 wavelength radiator blade dimensioning.

Abstract: A cable for use as a distributed antenna in intrusion detection systems comprises an internal open transmission line in parallel with a periodically loaded structure which supports an external transmission line mode of operation, specifically a surface wave, and is "driven" by the open transmission line. The periodically loaded structure may comprise transmission line segments for example cylindrical conductor elements intercoupled by serial inductive coupling. There are no fewer than three and no more than fifteen conductor elements in one wavelength (.lambda..sub.S) of the external transmission line modes. Preferably the length of each transmission line segment is about one quarter of the wavelength (.lambda..sub.S) of the external transmission line modes. The inductive coupling may be provided by resistance wires extending alongside the conductor elements.

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: A radio antenna which takes the form of a flexible elongated transmission cable. This cable encloses a pair of conductors which are insulated from each other. The cable is encased in an electrically conductive sheath. The received signal is picked up by the sheath and transmitted through an impedance matching network and into the pair of conductors. The length of the sheath is correlated to a preselected fractional value of the wavelength of the received signal.

Abstract: An antenna comprises a quarter-wavelength skirt antenna adapted to be disposed over an artificial ground and comprising a vertical cylindrical tube closed at the upper end and a coaxial feed inside the tube. The radiation pattern of the skirt antenna is essentially omnidirectional with a low elevation angle. The skirt antenna is combined with a helical antenna disposed vertically above the skirt antenna and coaxially therewith. The surface closing the upper part of the tube of the skirt antenna constitutes a reflective plane for the helical antenna favoring a hybrid radiation mode specific to the latter, partially axial and partially radial, by lowering the receive lobe of the radiation pattern towards an elevation angle suitable for receiving signals transmitted via satellite. A coupling device combines the signals received by each of the two antennas and feeds them to a common coaxial line.

Abstract: A base station for a mobile communications system including an antenna for transmitting a radio carrier wave to a mobile communications device and receiving signals therefrom, a coaxial external conductor including a skirt in the form of a sun shade having a length equal to a quarter wavelength of the radio carrier wave, a radio section located inside the coaxial external conductor for providing radio communication with the mobile communication device via the antenna, and a connecting section connecting the radio section to a telephone line and where the antenna is configured in the form of an upper disk of a discone antenna and where the skirt is a lower conical member of the discone antenna.

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 antenna (100) includes a quarter-wave monopole radiating element (110, 110') having a signal feed point end (110A). The antenna (100) further includes a reactive element (150) in the form of a conductive sleeve. The sleeve (150) includes a grounding end (150A) and is coaxially positioned around a portion of the monopole radiating element (110, 110'). A spacer (140) is coaxially situated between the monopole radiating element (110, 110') and the reactive element (150), for electrically insulating the monopole radiating element (110, 110') from the reactive element (150). The spacer (140) is sufficiently dimensioned such that the monopole radiating element is tightly coupled to the reactive element (150) at substantially around the feed point end (150A).

Abstract: Method and apparatus for in vivo or in vitro sensing of complex dielectric properties of lossy dielectric materials, particularly biological tissue. Configured as a needle-like dielectric sensor, a coaxial cable (1) having a circumferential gap (12) in the shield (2) is wrapped with an electrically thin dielectric substrate (18). The cable center conductor (6) extends immediately past gap (12) and is shorted to cable shield (2). A thin conductive dipole resonator (16) is positioned on substrate (18) and over feed gap (12) to achieve inductive coupling between the cable center conductor (6) and the dipole resonator (16) through gap (12). Superstrate (22), which could be a dielectric catheter, covers the entire sensor assembly (10). By measurement of the resonator resonant frequency and the input impedance matching factor at the resonant frequency, the real and imaginary dielectric components (.epsilon.', .epsilon.") of the test material into which the sensor is inserted are determined.

Abstract: A multiple-frequency stacked microstrip patch antenna structure is disclosed which provides substantially increased isolation between the multiple radiating elements and between the multiple feed elements. In one embodiment of the present invention having two radiating elements, such isolation is afforded by disposing shielding around a portion of the feed pin connected to the upper radiating element by electrically connecting the reference surface with the lower radiating element. Additional isolation and improved response characteristics can be provided by employing a tuning network for each radiating element. Additionally, two or more sets of stacked radiating elements can be arranged in an array to provide increased gain or directivity capabilities.

Abstract: An antenna system particularly suited for wind profiling produces a radio beam which can be oriented in each of four directions and optionally in a fifth, vertical direction and four intermediate directions. The antenna has a single array of strings of coaxial-colinear antenna elements. The strings are formed into sections, with each section having a first string portion formed of cable elements which are longer than one-half wavelength of the radio frequency drive signal in the cable and a second string portion formed of cable elements which are shorter than one-half the wavelength of the drive signal, with the two strings being connected together and mounted parallel to and above and below one another. Power is directed to the strings so that the radio frequency power flows in opposite directions in each string portion. The beam radiated from each string portion in each section adds to produce a beams tilted from the normal to the string portions by the same angle for both string portions.

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: The present invention pertains to an end-fed rod antenna which is tuned, e.g., to the VHF range and has additional transmitting and/or receiving antennas for the mm-wave range.

Abstract: A system for attaining an impedance match uses an array of collinear dipoles. By the shifting of the feedpoints away from the centers of the dipoles, the match may be made to any desired input feedpoint impedance.

Abstract: A discone antenna has a conducting cone having an apex and a conducting disc with a disc feed conductor extending from its center. The conducting disc is mounted at the apex of the cone in spaced relation therewith such that the disc feed conductor extends down into the cone through the cone's apex. A coaxial connector is mounted within the cone at the apex of the cone and defines a tuning cavity therein. A tuning slug is received in the tuning cavity through the apex of the cone and is vertically adjustable within the tuning cavity to tune the antenna.

Abstract: An antenna is provided which includes a half wave helical element RF coupled to a monopole element. The monopole element is situated on the axis of the helical element and extends into the helical element a distance sufficient to permit resonant coupling between the helical element and the monopole element. The monopole element is driven by a source of radio frequency energy such that the helical element coupled thereto is excited by such radio frequency energy.

Abstract: A leaky coaxial cable is designed to produce a defined coupling between its interior and exterior. A bonded and insulated outer conductor of relatively large width relative to the cable diameter, is spirally wound at a low pitch angle to provide at high frequencies a coupling level having minimal effect on the coaxial properties of the cable.

Abstract: In a system for launching RF energy as a traveling surface wave onto a single wire transmission line and causing such energy to be radiated away from the line at a downstream location, a series of window radiators of annular shape are spaced along the line, coaxial therewith, each for radiating a portion of the surface wave energy. Each radiator has a conductive component that causes decoupling and radiation of a portion of the RF energy, and a dielectric window that allows the remaining portion of RF energy to pass therethrough and continue, as an attached surface wave, downstream to a succeeding, similarly formed radiator where the decoupling and partial radiation occurs again. Thus, from the same surface wave transmission line system, it is possible to radiate RF energy from two or more discrete locations along the line.

Abstract: A three-wave common antenna for AM/FM and ultra high frequency waves combined in a single unit and mounted on vehicles including AM/FM antenna element mounted on a vehicle body at its base, a non-grounded type ultra high frequency antenna element disposed on top of the AM/FM antenna element such that the beam in a vertical plane thereof is close to the horizontal direction, a coaxial feeder cable for ultra high frequency which, along the AM/FM antenna element, is led into a vehicle body with one end thereof connected to the ultra high frequency antenna element, a characteristic compensating circuit connected to the AM/FM antenna element, and a feeder cable for AM/FM waves connected to the characteristic compensating circuit.

Abstract: An elongated active element for an antenna has an internal resonator providing a high quality matching impedance. The internal resonator is formed by a pair of conductors including an outer conductor and a coaxial inner conductor that is connected to signal ground. The signal connection of the active element is made to one end of the outer conductor in the neighborhood of the ground connection to the inner conductor. The inner conductor is shorted to the outer conductor at approximately a quarter of a wavelength, plus an integral number of half wavelengths, from the signal and ground connections to provide a parallel-resonant condition complementing the series resonant characteristics of the radiation impedance of the active element. Preferably, the active element is approximately a quarter wavelength long, and may be lengthened or shortened to obtain a desired radiation resistance. The antenna is easily fabricated from a length of coaxial cable.

Abstract: A vertically polarized array comprised of both bottom fed and top fed conurations having a driven element comprising at least one but, when desirable, two generally horizontal wire conductor segments of a length substantially equal to one half the operating wavelength of the array and with the ends of the half-wave conductor segments being connected to or extending into generally vertical quarter wavelength wire conductor segments. In a bottom fed configuration the feedpoint is at the bottom end of one vertical quarter wavelength conductor segment while in a top fed configuration one vertical quarter wavelength segment comprises a quarter wavelength of coaxial transmission line having one end configured into signal isolation means, comprising a cable choke, while the feedpoint is located at the other end.

Abstract: An antenna, suitable for being deployed from an aircraft or other vehicle and characterized by broadband, omnidirectional radiation/reception is provided by a coaxial transmission feed line that is terminated by an electrically conductive ball that is electrically and mechanically connected to an extension of the center conductor of the coaxial line, and by a telescopically adjustable sleeve choke having the end adjacent the ball conductor, electrically bonded to the outer conductor of the coaxial line. The choke is adjusted in length to form a matched counterpoise to the ball radiator.

Abstract: A modified line antenna, having reduced length and space of occupancy, each element of which is divided into a plurality of segments which are made of coaxial lines connected in series with a novel inventive technique and folded into a short and compact structure at the points of connection without any loss of overall efficiency.

Abstract: A linearly polarized omnidirectional antenna includes one or more dipoles having an elongated tubular conductive radiator of a length that is about half the wavelength of the midband frequency, and an elongated inner conductive member extending longitudinally through the interior of the radiator and spaced therefrom. A coaxial cable or other feed means conducts signals to and from one end of the radiator and to and from the inner conductive member. The impedances of the dipole and the feed means are matched over a selected frequency band, such as by the use of a series inductive reactance between the feed means and the radiator. Two such dipoles can be connected to a colinear, center-fed pair, and two or more such dipole pairs can be arranged in a colinear array having a common inner conductive member.

Abstract: A VHF monopole antenna unit, particularly adapted for operation in the 30 MHz frequency range, yet capable of embodiment in a compact structure only approximately 11/2 feet in height is described. Coarse tuning is accomplished in a number of switched bands, for each of which is provided a specially designed matching network comprised of inexpensive L-networks of inductors and capacitors. Tuning is accomplished through adjustment of inductor elements. The simple, inexpensive design of the matching circuits eliminates need for intricate mechanisms typically used for automatic impedance matching over a wide band and also for a broadband impedance matching transformer. The compactness made available by the unique top-load structure design is further made possible by provision of a specially designed dielectric filled vertical antenna element, accomplishing the same range and efficiency in an even more compact antenna.