Abstract: A coaxial type impedance matching device includes a matching device body including an external conductor and an internal conductor arranged in the external conductor, an input side dielectric disposed in the matching device body and including a first dielectric and a second dielectric, and an output side dielectric disposed in the matching device body and including a third dielectric and a fourth dielectric. Distance between opposed surfaces of the first dielectric and the second dielectric is a predetermined distance, which is in a range of N?/4??/6 to N?/4??/6, where ? represents a guide wavelength of an input signal in the matching device body and N represents odd number. Distance between opposed surfaces of the third dielectric and the fourth dielectric is the predetermined distance.

Abstract: The present invention discloses a low-cost coaxial cable fed inverted-L antenna with a structure using only one coaxial cable and extending an internal conductor outside one end of the coaxial cable to a predetermined length outside an external conductor on the other end, and then bending the coaxial cable backward in an opposite direction along the external conductor and parallel to the direction of the external conductor to extend to a predetermined length outside to define a radiating member, which doesn't require additional components or any other manufacturing procedure, and will greatly lower the production and manufacturing costs of the antenna and improve the yield rate of production.

Abstract: A wideband antenna system is capable of radiating or receiving signals in a low-frequency band [Fbb, Fbh] covering more than one octave and a high-frequency band [Fhb, Fhh] with Fhb>=2Fbh comprising at least one power supply device (4) powering at least one upper radiating element (1) and at least one lower radiating element (2). The lower radiating element (2) is provided with at least one antenna assembly (10) adapted to radiating in the high-frequency band [Fhb, Fhh]. Application to RF signals. FIG. 3 to be published.

Abstract: A complex antenna apparatus including a base, a circular polarization antenna and a capacitance (inductance) cylinder loading monopole antenna. The base has a central through hole. The circular polarization antenna is disposed on the base and has a hollow feeding portion corresponding to the central through hole. The capacitance (inductance) cylinder loading monopole antenna is fixed on the base by inserting one end of the capacitance (inductance) cylinder loading monopole antenna into the central through hole.

Abstract: A dual-frequency broadband antenna mainly comprises a dipole antenna set and an inductive shield, in which a positive and a negative pole are substantially two cup-like tubular hollow poles spaced out from a distance apart equal to ¼&lgr; of a high frequency band approximately; and the inductive shield is a tube made of an insulating material, having a open end. The dipole antenna set is assembled in a cavity of the inductive shield without contacting the inner rim of the latter.

Abstract: A wireless communication system for closed environments including a plurality of antennas parallel line coupled to the coaxial cable of a coaxial cable radio frequency transmission system. Each antenna includes a quarter wavelength long conductor positioned between the center and outer conductors of the coaxial cable. The conductor is axially aligned to the cable and insulated from the center and outer conductors by the cable's dielectric core. The conductor is connected to a quarter wavelength radiator supported by a conductive bar clamped to the exterior of the coaxial cable.

Abstract: An antenna unit and a computing system utilizing the antenna unit are disclosed. The antenna is compact and can be fabricated at low cost and with high accuracy. The antenna unit comprises an antenna and a connection cable. The antenna unit is constructed by forming the antenna and the connection cable integrally on a preferably flexible insulating film using preferably the FPC (Flexible Printed Circuit) technique. The computing system comprises a body having its main operational circuits and a hinged cover having a display. The flexible printed antenna is formed integrally with its module of electric components using the FPC technique and is made to span the body and the cover. The antenna itself and the connection cable can be freely bent or folded, resulting in higher freedom in their positioning within the computer system body and cover.

Abstract: The present invention provides a support for an antenna. In particular, the present invention provides a substrate with conductive transition pads for a co-linear coaxial antenna array. The transition pads are constructed and arranged to properly provide power and phase shifting to the antenna array.

Abstract: The present invention is to provide to a planar multiple band omni radiation pattern antenna having first and second patch lines printed on a planar dielectric substrate material, wherein a plurality of radiation members are formed bifurcately, symmetrically along both sides of a longitudinal axis of either patch line. Each of the radiation members comprises at least two post-shaped conductors each having a length slightly less than one-quarter wavelength of a central frequency of each operating frequency so as to form a choke and the radiation members of multi-frequency, and enable the operating frequencies not to be harmonically related.

Abstract: The invention relates to an antenna of colinear type.

Abstract: A substance structure of a dual-band dipole antenna, it consists of: an internal conductor, which is formed by a lead coated with an internal insulation layer; an external conductor, which is formed by a grounding layer coated or coiled to the said internal insulation layer, and an external insulation layer coated to the grounding layer; and a metal tube with a tip connected with the external conductor; thus, by means of the exposed end section of the internal conductor that is diverged into two branches, a dual-band dipole antenna is accomplished.

Abstract: The present invention relates to a collinear antenna structure. The structure comprises a dipole antenna, a coil, and a set of stacked radiator, wherein the length of the dipole antenna is ½&lgr;, the ground end and the signal end of the dipole antenna are connected to a coaxial cable, the length of the cable line is less than ¼&lgr;, one end of the cable line is connected in series to the top of the signal end, wherein the stacked radiator comprising at least two parallel radiators in series, the length of each radiator is ½&lgr;, the distance between the two radiators is about 1.0 to 4.0 mm, one of the stacked radiator is axially connected in series to the other end of the coil, thus forming the structure of the antenna.

Abstract: A conventional method for giving reducing properties uses medication or medium and thus, a range in which the method can be utilized is limited, and there is apprehension that the method adversely affects the environment of ecological system. Further, an apparatus for giving reducing properties is large in scale, and there is an adverse possibility that the apparatus adversely affects other electronic equipment. It is an object of the present invention to solve these problems. A plurality of coaxial cables are arranged as radiators 3 in a form of comb teeth-like shape. Each of the coaxial cable has a predetermined length and a dielectric 3c between an internal conductor 3a and an external conductor 3b. The coaxial cables are connected to an oscillator in series for supplying high frequency alternating current.

Abstract: A multi-band radial horn antenna is disclosed that has a precision 50 ohm feed air line to ensure a match to a 50 ohm transmission line. The feed probe of the antenna has a threaded section that allows the antenna to be tuned quickly and precise in the field to provide maximum antenna performance. Once adjusted, a small locking nut is tightened to retain the physical location position. The antenna is economical to build as it has only four major parts. In operation, the antenna was found to have a 1.15 to 1 Standing Wave Ratio, a decade of frequency bandwidth and a low angle of radiation.

Abstract: A wideband antenna system is capable of radiating or receiving signals in a low-frequency band [Fbb, Fbh] covering more than one octave and a high-frequency band [Fhb, Fhh] with Fhb>=2Fbh comprising at least one power supply device (4) powering at least one upper radiating element (1) and at least one lower radiating element (2). The lower radiating element (2) is provided with at least one antenna assembly (10) adapted to radiating in the high-frequency band [Fhb, Fhh]. Application to RF signals.

Abstract: A common aperture UHF/horizontally polarized low- and mid-band VHF antenna is disclosed that includes a coaxial antenna that has an inner conductor, an outer conductor, a batwing assembly mounted to the outer conductor of the coaxial antenna, and a feed line for feeding the batwing assembly separate from the coaxial antenna. The disclosed slotted coaxial antenna accomplishes simultaneous UHF and VHF broadcast.

Abstract: A transceiver, which may be a telephone for mobile networks, includes a metal or screened casing, an antenna support mounted on the casing at one end of the antenna support, and an antenna mounted on the other end of the antenna support. The antenna support has a physical or electrical length substantially equal to one quarter of the wavelength of waves emitted by the antenna. The transceiver has improved link efficiency.

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: 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 multi-band radial horn antenna is disclosed that has a precision 50 ohm feed line to ensure a match to a 50 ohm transmission line. The feed probe of the antenna has a threaded section that allows the antenna to be tuned quickly and precise in the field to provide maximum antenna performance. Once adjusted, a small locking nut is tightened to retain the physical location position. The antenna is economical to build as it has only four major parts. In operation, the antenna was found to have a 1.15 to 1 Standing Wave Ratio, a decade of frequency bandwidth and a low angle of radiation.

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: 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: 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: The dual polarization antenna includes a substrate having a ground plane and a dielectric layer adjacent thereto, and at least one antenna unit carried by the substrate. The antenna unit includes four adjacent antenna elements arranged in spaced apart relation from one another about a central feed position on the dielectric layer opposite the ground plane. Preferably, diagonal pairs of antenna elements define respective antenna dipoles thereby providing dual polarization. The antenna unit also includes an antenna feed structure having four coaxial feed lines, each coaxial feed line including an inner conductor and a tubular outer conductor in surrounding relation thereto. The outer conductors have parallel adjacent ends joined together about an axis and are connected to the ground plane. The ends of the outer conductors are tapered and arranged so that portions thereof adjacent the axis extend further beyond the ground plane in the dielectric layer and toward the antenna elements.

Abstract: A cable antenna includes a circuit board to which first ends of two antenna cables and a coupling cable are soldered. A second end of the coupling cable forms a connector for connection with a signal receiving/transmitting circuit. Each of the antenna cables has a second free end exposed to the atmosphere for receiving/transmitting electromagnetic signals. An outer jacket of each antenna cable is removed along a first predetermined length measured from the free end thereof to expose a braided shield. A second predetermined length of the braided shield measured from the free end is removed for exposing an inner dielectric layer that surrounds a core conductor. The second length is less than the first length thereby leaving a portion of the exposed braided shield on the inner dielectric layer. The braided shield that is cut from the cable is twisted to form an elongate consolidated conductor.

Abstract: A holder is eliminated when installing an antenna to a radio case, the installation operation is simplified, and a feeding mechanism is improved. A slit is provided in a stopper of an antenna so that the outer diameter can be reduced, and the antenna is inserted directly into a cylindrical section of the radio case from the bottom of the stopper. A plate-like feeding spring is provided at the cylindrical section, and is directly attached to a connection point of a circuit substrate of a radio; one end of the plate-like feeding spring pressingly contacts the side of the stopper of the antenna, thereby forming a feeding mechanism.

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 assembly for transmitting a radio signal from a radio signal transmitting device includes an antenna unit comprised of a dipole driven antenna member for transmitting a radio signal from the radio signal transmitting device. A radiation reflector reflects the radio signal transmitted by the driven antenna member, and a support member supports the driven antenna member and the radiation reflector so that a predetermined gap is precisely maintained between the driven antenna member and the radiation reflector. A shielding member shields a portion of the radio signal transmitted by the driven antenna member in a direction toward the shielding member. The antenna unit is pivotally mounted so that it is disposable at selectable positions relative to the shielding member. The output of the radio signal transmitted by the driven antenna member can be controlled depending on a position of the antenna unit. The dipole driven antenna member comprises a first and a second segment made from a metal foil.

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 with a simple and compact structure includes an inductor, first and second rod-like radiating elements connected to opposite ends of the inductor, with dielectric material surrounding both the inductor and the joining portions of the first and second radiating elements on the respective ends of the inductor. A conductive housing surrounds the dielectric and supports the inductor and the joining portions of the first and second radiating elements. The housing and dielectric create a capacitance, so that an LC resonant circuit is formed in conjunction with the inductor. The LC circuit is designed such that only one radiating element radiates at the higher band of the dual operating band, whereas both radiating elements radiate at the lower band.

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: An UHF antenna system having inner antenna conductor and an outer antenna conductor having end caps. The inner conductor is supported by one of the end caps. This provides an electrical short to the outer antenna conductor and a thermal short to ambient.

Abstract: A switched gain antenna array comprising a plurality of dipole elements disposed in series with a phasing stub coupled between adjacent ones of the dipole elements. An antenna feed line is coupled to a first one of the dipole elements to couple the RF signals into and out of the plurality of dipole elements. The phasing stubs are adapted to adjust phase of the RF signals provided to each of the dipole elements so that the dipole elements operate in phase. A switch is disposed between the first one of the dipole elements and a second one of the dipole elements. The switch is adapted to disconnect the first one of the dipole elements from remaining ones of the dipole elements during transmit operations of the antenna array and to connect each of the dipole elements together during receive operations of the antenna array. As a result, the antenna array has greater gain during receive operations than during transmit operations.

Abstract: The present invention relates to antennas and in particular relates to a multi-resonant antenna. The present invention addresses the requirement for dual frequency antennas operable in two distinct frequency bands. In accordance with a first aspect of the invention, there is provided a multi-resonant antenna comprising first and second conductive elements which antenna elements extend relative to a ground plane; wherein the elements of the antenna structure are adapted to couple between themselves to provide a variable phase velocity for surface currents of the radio signals. A method of operation is also disclosed.

Abstract: A stable coaxial antenna for broad band and narrow band applications is described. The antenna disclosed is preferably made of a conventional coaxial cable having a center conductor, tubular outer conductor surrounding the center conductor and an insulator between the conductors. A gap is formed in at least the outer conductor to form two outer conductor sections. In a first embodiment the field is provided between the gap and a feed end. In a second embodiment the gap is between both center and outer conductors and the ends of the conductors in the gap are cross connected to form a radiating section and feed section. The coaxial antennas disclosed may be adjusted to synchronize the energy to react favorably to an uncontrolled environment.

Abstract: The invention relates to a particular structure of high-frequency antenna, which comprises a support element (1) provided with a cylindrical coil conductor which forms a helix (2). On the support element (1) there is formed, for example by means of a conductive coating, the electrical parts of the antenna, such as the attachment points (3b) for the helix and for other parts, such as feeder lines (4), radiators (5) or impedance matching devices. By varying the number and size of the helices (2), the number and form of the feeder lines (4) and radiators (5) and the quality of any impedance matching devices, it is possible without difficulty to obtain a very wide choice of different antenna structures. The feeder lines and radiators extend, at least in part, within the helix.

Abstract: An antenna (100) operable over a predetermined broad band and connected to a transmission line (102) includes a tip radiator (106) having a series capacitance (129) and a base radiator/choke (104) operatively connected to the tip radiator for changing feed point reactance values to values that provide a desired bandwidth to minimize the antenna's voltage standing wave ratio (VSWR) over frequencies in the predetermined broad band. The antenna also includes a choke assembly (108) operatively connected to the transmission line for suppressing current below a predetermined point of the antenna to maintain the desired bandwidth and VSWR.

Abstract: The present invention provides a radio communication device having a multi-band swivel antenna assembly. The antenna assembly includes a multi-band radiating antenna element and a multi-band sleeve which allows the antenna to be tuned to multiple resonances. The multi-band antenna element and sleeve are attached to the chassis of the communication device via a coaxial feeding cable which serves to isolate those elements from the chassis.

Abstract: The present invention provides a microstrip collinear antenna having cable connector assembly means and a collinear microstrip printed circuit board means. The cable connector assembly means responds to a radio signal, for providing a cable connector assembly radio signal. The collinear microstrip printed circuit board means responds to the cable connector assembly radio signal, for providing a collinear microstrip printed circuit board radio signal. The microstrip line collinear antenna is constructed with a number of one half .lambda. printed circuit board elements on both sides of a double-sided board. These one half .lambda. sections are the radiators. On the other side of the board opposite each radiator is a respective section of corresponding microstrip transmission lines to provide radio frequency power to each radiating element.

Abstract: An antenna structure includes a center feed dipole antenna having first and second radiating sections that extend along a substrate from a center feed point. A feed section is electrically coupled to the center feed point. The feed section includes a radio frequency input line and a ground line extending along the substrate adjacent one another. A balun extends along the substrate between the first radiating section and the ground line. The first radiating section, the radio frequency input line, the ground line and the balun preferably extend along the substrate in parallel. A tuning shunt may also be provided across the balun for dual band operation. Accordingly, compact dual band antenna structures including baluns may be provided.

Abstract: A novel and improved dual band antenna system comprising an inner antenna element surrounded by an outer antenna element. In a first embodiment, the inner antenna element radiates and receives RF signals in a first RF band, and the outer antenna element radiates and receives RF signals in a second RF band. Optionally, the inner and outer antennas may be coupled together when operating in the first RF band in order to improve the antenna gain pattern of the dual band antenna. In a second embodiment, the inner antenna element radiates and receives RF signals in both the first and second RF bands. In this second embodiment, when operating in the second RF band, the outer antenna element is grounded, thus altering the signal length of the inner antenna element to resonate in the second RF band.

Abstract: A conformal antenna assembly disclosed has a first antenna portion sensitive to a UHF band of frequencies. A thin, flat, low-profile, weather-resistant housing encloses the first antenna portion. The housing has a conformal back surface that conforms to the shape of a support surface on which said housing is mounted. The housing has an arrangement to mount the housing to a support surface. In one form the housing is flat to mount on the side of a building and in another form is double curved to mount on the back of a satellite dish. A coaxial cable has a center conductor and a tubular outer conductor with an insulator between the conductors. The center conductor and outer conductor are connected at one end to the first antenna portion. The inner conductor terminates at the other end in an end terminal to conduct signals from the first antenna portion to the end terminal.

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 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 monopole antenna for aircraft, vehicles, marine vessels and the like comprises a coaxial cable radiator and a metal tube radiator surrounding the lower half of the coaxial cable. The center conductor of a coaxial cable connector applies radiant energy to the jacket of the coaxial radiator. The center conductor of the coaxial radiator extends from the bottom of the cable and is connected to the outer lower surface of the metal tube radiator. In operation, the distributed L-C and R-C values at resonance couple radiation energy to the metal tube radiator while the tube suppresses radiation from the jacket except for radiation from the upper portion thereof. Tests comparing the radiation pattern of the above antenna without ground plane and a conventional monopole antenna with ground plane indicate that the radiation pattern is extended in the forward, axial (zero degree) direction although some loss occurs in the + and -90 degree direction.

Abstract: A base station antenna includes a matching network that broadbands transmission without requiring adjustment. Using a one-quarter wavelength (1/4 .lambda.) or less sperrtopf sleeve in a coaxial arrangement, broadbanding is achieved by adding a second conductor parallel to the transmission line center conductor. A ring inductor is tapped at one end off-center by the second conductor. The inductor's step-up end is connected to the antenna with the primary end connected to the transmission line center conductor. Mutual inductance may be present, but is not required, between the transmission line center and second conductors. Fringing capacitance between the antenna and the sleeve establishes an "L" network in conjunction with the inductor. To protect the inductor from the elements, it is placed inside the antenna near the sleeve.