Abstract: A dual mode antenna system for a wireless transceiver is provided, and includes a retractable antenna element having a first, retracted position and a second, extended position. The antenna element operates as a first type of antenna in the first position and a second type of antenna in the second position. In the first position, the retractable antenna element is connected to a loading structure to form a low-profile antenna, and in the second position, the antenna element forms a monopole antenna.

Abstract: A radio frequency communication device and methods of testing and tuning an antenna attached thereto are disclosed. A radio frequency communication device according to the present invention is disclosed comprising internal circuitry and an antenna having a plurality of antenna segments associated therewith. Each antenna segment is associated with the antenna in either series or parallel relation through at least one of a fuse and an antifuse. In testing and tuning, a comparison is made to indicate whether the antenna is too short or too long. If the antenna is too short, an antenna segment may be attached to the antenna by initiating an antifuse. If the antenna is too long, an antenna segment may be detached from the antenna by blowing a fuse. If it is indeterminate whether the antenna is too short or too long, an antenna segment may be either attached or detached, the test repeated, and the results of the repeated test compared with the prior test to determine whether the correct action was taken.

Abstract: A spiral antenna having a horizontal member that terminates wires for conducting and radiating signals provides increased efficiency over the HF transmission range in a smaller size construction. A load having a parallel RLC circuit is provided at about the center of the horizontal member. The wires are provided in an elliptical pattern with the spacing between wires provided arithmetically. The wires are further configured symmetrically around a vertical support member. A balun transformer is also provided for impedance matching with a feed line.

Abstract: An electromagnetic bandgap material is electrically attached to an edge, and enables high isolation between antennas due to the attenuation of surface waves. The disclosed embodiments further provide narrow reactive edge treatments in the form of artificial magnetic conductors (AMCS) whose physical width is less than {fraction (1/10)} of a free space wavelength for the frequency of surface currents intended to be suppressed. These embodiments still further provide several AMCs suitable for this purpose, along with several exemplary manufacturing techniques for the AMCs.

Abstract: A monopole antenna for use with at least two wireless communication services, having a monopole element (10) disposed along a straight line (11) and connected with a roof capacitor (1) that is designed as a flat area, the area normal line (12) pointing in the direction of the straight line (11). The roof capacitor (1) has rotational symmetry, and is formed by flat ring structures (2) that are separated from one another by ring-shaped gaps (3), the structures being oriented concentric to the straight line (11). Reactance circuits (4) connect the ring structures (2) with one another so that they are active for a wireless communication service having the lowest frequency, and the outermost ring structure (2) is essentially ineffective for the wireless communication service having the next higher frequency, because of the high impedance of the reactance circuit (4).

Abstract: A quadrifilar helix antenna is provided having a feedpoint for the antenna connecting to individual helical antenna elements. A capacitive network, distributed along the length of the antenna, constitutes a variable frequency shunting network. At each position a first capacitive structure, that may comprise a single capacitor or multiple capacitors in series, interconnects a first pair of opposite antenna elements; a second capacitive structure interconnects the second pair of opposite antenna elements. As an applied frequency increases, the capacitive structures progressively short the opposite antenna elements thereby electrically reducing the antenna length.

Abstract: A monopole wire-plate antenna comprising a ground plane (10), a first radiating element in the form of a capacity top (11, 12) adapted to be connected to a generator, and a second radiating element in the form of a conductor wire (14, 14′, 15, 15′) connecting the capacity top to the ground plane is disclosed. It comprises a plurality of at least one of said radiating elements.

Abstract: An antenna arrangement comprises a patch conductor (102) supported substantially parallel to a ground plane (104), a feed pin (106) connected to the patch conductor at a first point and a ground pin (108) connected between a second point on the patch conductor and the ground plane. The feed and ground pins are connected by a linking conductor (510) and have shunt capacitance means coupled across them. Suitable values of the capacitance means and the location and dimensions of the linking conductor enable a good match to the antenna to be achieved. The linking conductor may be directly connected to the patch conductor or there may be gaps between the feed and ground pins both above and is below the linking conductor. An impedance transformation may be provided by the feed and ground pins having different cross-sectional areas and/or by the provision of a slot in the patch conductor.

Abstract: A dual mode, substantially planar antenna utilizes a dipole or monopole structure for receiving and transmitting high-frequency signals. Layers of conductive strips are disposed on opposite sides of an insulating (dielectric) substrate, such as printed circuit board material. First and second antenna elements are connected via an LC trap, the first antenna element corresponding to a first mode and the combined elements corresponding to a second mode. The LC trap is a single component inductor with parasitic capacitance sufficient to implement the LC trap or a set of patterns printed on the substrate. In one embodiment, the LC trap is constructed with only a single via through the substrate. The antenna is ideally suited for combined 5.5 GHz and 2.4 GHz RF operations.

Abstract: A wideband meander line loaded antenna is provided with a capacitive feed to lower the reactance of the meander line antenna such that at lower frequencies the antenna reactance goes negative to cancel out the reactance of the meander line and distributed capacitance. The resultant lowering of the low frequency cut-off for the antenna permits the antenna to be used, for instance, in cellular phone applications in which not only are the cellular frequencies accommodated by the antenna, but also PCS and GPS frequencies as well. With the capacitive, feed the low frequency cut-off is lowered by as much as 30% over standard meander line loaded antennas.

Abstract: A multi-resonant antenna device of the present invention contains an antenna element 22 and an LC parallel resonance circuit 31 making the antenna element 22 resonate in a plurality of frequency bands, and the LC parallel resonance circuit 31 contains a T-type circuit or PI-type circuit composed of an inductance element 26, acting as a shunt element, and capacitance elements 29 and 30, which prevents the impedance from becoming infinite in a certain frequency band. In this way, a drop, that is, a notch portion, in the frequency characteristic causing deterioration of the gain can be eliminated.

Abstract: A dual-polarized, stub-tuned, proximity-fed, stacked patch antenna includes a ground plane layer and a dielectric substrate overlying the ground plane layer. An active patch antenna element is disposed on the dielectric substrate. A parasitic patch antenna element is supported in spaced relation to the active patch antenna element. Dual feed lines are spaced from and field-coupled to the active patch antenna element. Each feed line has a tuning stub for producing a distributed antenna resonance. The dual feed lines are configured to provide dual polarization and minimize coupling between the feed lines. The feed lines are positioned substantially orthogonal to each other to provide orthogonal linear polarizations. Each feed line includes a feed line tip that extends towards the center of the active patch antenna element and spaced from each other to minimize tip-to-tip coupling. Each feed line tip includes a 90 degree bend.

Abstract: A beam steering, frequency agile antenna having low insertion loss, fast tuning speed, high power-handling capability, high IP3 and low cost in the microwave frequency range. The beam steering, frequency agile antenna comprising an array of antenna elements, said antenna array elements loaded with tunable dieletric capacitors in order to tune their frequency response; and an electronic phase shifter controlling said array of antenna elements in order to spatially scan the main radiation beam, said tunable dielectric capacitor comprising a substrate having a low dielectric constant with planar surfaces, a tunable dielectric film on said substrate of low loss tunable dielectric material, metallic electrodes with predetermined length, width, and gap distance; and low loss isolation material used to isolate an outer bias metallic contact and a metallic electrode on said tunable dielectric.

Abstract: An improved tuning method is used in conjunction with a set of nested electrically conducting cones to increase the frequency band over which the resulting radiating system functions as an electrically small antenna with controlled variation in input impedance. This technique enables switching of the frequency band by means of simple circuits that can be activated by a control voltage.

Abstract: An antenna device having a high gain is presented. The device includes an antenna element, a variable capacitor disposed closely to the antenna element and connected to the antenna element in series or parallel to form a resonance circuit, a tuning voltage supply terminal for supplying a tuning voltage for varying a capacitance of the variable capacitor, and an signal power terminal capable of at least one of sending a signal power to the resonance circuit and receiving a signal power from the resonance circuit.

Abstract: The invention is a low profile antenna array, particularly beneficial for AM broadcasting stations, which dramatically reduces the height of the antenna. The antenna array is constructed of at least two conductors oriented horizontally or sloping slightly up and extending away from a center location where they have upright sections extending above the ground plane by as little as 0.01 wavelength. The individual conductors are each approximately one-quarter wavelength long. The multiple conductors of the antenna array are each fed by impedance matching sections to achieve high individual impedances, which, when connected in parallel can be made to match any desired impedance with dimensional changes.

Abstract: A broadband loaded antenna and matching network with related methods for design optimization are disclosed. The loaded antenna structures may preferably be either monopole or dipole antennas, but the particular methods and techniques presented herein may be applied to additional antenna configurations. The load circuits positioned along an antenna may comprise parallel inductor-resistor configurations or other combinations of passive circuit elements. A matching network for connecting an antenna to a transmission line or other medium preferably includes at least a transmission line transformer and a parallel inductor. Various optimization techniques are presented to optimize the design of such broadband monopole antennas. These techniques include implementation of simple genetic algorithms (GAs) or micro-GAs. Component modeling for selected components may be effected through either lumped element representation or curved wire representation.

Abstract: An antenna assembly (10) for RF communication of signals representing utility meter data. The antenna assembly (10) comprises a first conductor (30) forming at least a portion of an antenna radiating element, a second conductor (28), and a dielectric (34) disposed between the first conductor (30) and the second conductor (28), such that the first conductor (30), the second conductor (28) and the dielectric (34) form a capacitor. The antenna assembly (10) further comprises an inductance (36) in cascade with the capacitor to provide a selected L-C circuit impedance in relation to the antenna radiating element. The second conductor (28) is disposed opposite to the first conductor (30) and at least one of the first and second conductors (28, 30) is movable from a first to a second position to adjust the capacitance of the L-C circuit to a selected frequency of operation.

Abstract: The invention is a low profile antenna array, particularly beneficial for AM broadcasting stations, which dramatically reduces the height of the antenna. The antenna array is constructed of at least two conductors oriented horizontally or sloping slightly up and extending away from a center location where they have upright sections extending above the ground plane by as little as 0.01 wavelength. The individual conductors are each approximately one-quarter wavelength long. The multiple conductors of the antenna array are each fed by impedance matching sections to achieve high individual impedances, which, when connected in parallel can be made to match any desired impedance with dimensional changes.

Abstract: A dual mode, substantially planar antenna utilizes a dipole or monopole structure for receiving and transmitting high-frequency signals. Layers of conductive strips are disposed on opposite sides of an insulating (dielectric) substrate, such as printed circuit board material. First and second antenna elements are connected via an LC trap, the first antenna element corresponding to a first mode and the combined elements corresponding to a second mode. The LC trap is a single component inductor with parasitic capacitance sufficient to implement the LC trap or a set of patterns printed on the substrate. In one embodiment, the LC trap is constructed with only a single via through the substrate. The antenna is ideally suited for combined 5.5 GHz and 2.4 GHz RF operations.

Abstract: A wideband meander line loaded antenna is provided with a capacitive feed to lower the reactance of the meander line antenna such that at lower frequencies the antenna reactance goes negative to cancel out the reactance of the meander line and distributed capacitance. The resultant lowering of the low frequency cut-off for the antenna permits the antenna to be used, for instance, in cellular phone applications in which not only are the cellular frequencies accommodated by the antenna, but also PCS and GPS frequencies as well. With the capacitive, feed the low frequency cut-off is lowered by as much as 30% over standard meander line loaded antennas.

Abstract: A broadband folded dipole antenna has a pair of load resistors in the vicinity of the edges of the antenna element for obtaining a unidirectional beam pattern.

Abstract: A patch antenna device includes an antenna patch, and one or more capacitors loaded into the antenna patch for increasing an equivalent working area to the antenna patch. The capacitor may be any suitable capacitor, such as the chip capacitor. The provision of the capacitor into the antenna patch allows the electricity to flow into and to flow out of the capacitor, and consumes less electric power. A ground board and a dielectric plate are attached to the antenna patch. One or more feeds and probes are loaded into the antenna patch for exciting various modes.

Abstract: A directionality switching antenna apparatus of the present invention is provided with radiator 102 in folded form, folded at a length of predetermined length from a feeding point of ground plane 101, with one end thereof connected to the feeding and with the other end thereof shorted with ground plane 101, a plurality of parasitic elements 103 spaced in the vicinity of radiator 102 each with an element length set to provide the parasitic elements with an electrically symmetrical relation to the center axis of radiator 102, inductors 104 loaded on respective parasitic elements 103, diodes 105 connected to ground plane 101, switching elements 106 that connects in parallel respective inductors 104 and respective diodes 105 between respective parasitic elements 103 and ground plane 101.

Abstract: An antenna (20) operable over a predetermined range of frequency includes a transmission line (36), a transformer network (42) connected to one end of the transmission line, and at least one inductor-resistor network (46) connected to an opposite end of the transformer network. The inductor-resistor network (46) changes the effective electrical length of the antenna (20) such that as the frequency of operation changes, the current distribution above and below the inductor-resistor network changes in a corresponding manner. A second inductor-resistor network (56) may be serially connected to the other network (46), wherein both function to reduce the current thereabove. Accordingly, as the frequency of operation increases, the electrical height of the antenna decreases.

Abstract: The invention concerns detachable whip antennae with capacitive load wherein the load does not need to contribute to the antenna mechanical strength. To achieve this, the entire load (3) is inserted in the conductor strand (2f-21-33-32-2n) of a radiating segment of the antenna, the mechanical strength being provided by a hollow plastic insulating tube (20) reinforced with glass fibres, which acts as support for the conductor strand and as housing for the load and said load consists of a metal enclosure (33) wherein penetrates the insulated part of an electric cable (32). The invention is particularly applicable to whip antennae designed for mobile stations.

Abstract: An antenna with a loading coil (26), is constructed with the spacing between turns of the coil and the diameter of the coil being precisely fixed in a mass-produced loading coil. Three rib members (80, 82, 84) are provided that have slots (90) that receive the turns of the coil, with the rib members being circumferentially spaced about about the axis (32) of the coil. The lower ends (94) of the rib members are fixed in radial position to the bottom (144) of the loading coil frame (140), and the upper ends (92) of the rib members are connected to a ring (130) that braces the tops of the rib member to each other and that expands the diameter of the upper portion of the coil, to form a rigid combination of coil and rib members.

Abstract: A ferrite core antenna having two spaced signal pick-up coils coupled through a transformer so that the signals from the two coils are additively combined in the primary of the transformer. A variable capacitor connected to the two coils tunes the antenna to selected frequencies. This results in amplification of the signal.

Abstract: An improved tuning method is used in conjunction with a set of nested electrically conducting cones to increase the frequency band over which the resulting radiating system functions as an electrically small antenna with controlled variation in input impedance. This technique enables switching of the frequency band by means of simple circuits that can be activated by a control voltage.

Abstract: A disk antenna for use in a PCMCIA card or the like having a disk made from conventional moldable plastics and a radiating element that has a low capacitive impedance relative the inductance of the antenna feed such that the tuning element is capacitive. The disk antenna maximizes the ratio of bandwidth to disk size by maximizing the surface area of the radiating element. The antenna is application specific in that it can be adapted for various environmental resonant variations.

Abstract: In a preferred embodiment, a spiral or helical antenna offering expanded operation at low frequencies while retaining a package size roughly equivalent to an unmodified antenna having a bandwidth not extended in low frequency. A preferred embodiment is a planar spiral antenna incorporating a pair of spiral arms, one arm of which has been modified to incorporate a capacitance at selected intervals along upper and lower surfaces of that arm so as to cause a phase shift in one of the input signals to the antenna. The input signal is provided by splitting at a balun a single signal into two equal amplitude signals 180° out of phase with each other. The subsequent phase shift permits the two out of phase input signals to be brought back into phase at calculated intervals prior to termination of the signals at the arms' ends.

Abstract: An antenna element (1) includes, a film (10) of dielectric material having thereon a radiating antenna element (14) that radiates at a first order harmonic frequency within a desired first frequency band, a conducting capacitive load element (90) and the radiating antenna element (14) being capacitively coupled across a thickness of the film (10) at a second order harmonic frequency, to tune a radiated second order harmonic frequency to correspond with a desired second frequency band, thereby providing a dual band antenna element (1).

Abstract: An earthing conductor is disposed on the reverse of a print board, and a signal process circuit section including a transmit-and-receive circuit is disposed on the right side of the board. A loading coil is mounted on the right side of the board across a print pattern of the signal process circuit section and a print pattern of an antenna. A vertical portion of the antenna projects from the print pattern of the antenna on the print board, and a horizontal portion of the antenna horizontally extends from a top end of the vertical portion in parallel with the print board.

Abstract: A dual band antenna (12) includes a coil (14) and a reactive element (30). The coil (14) has a plurality of windings (20) including first and second selected windings (22,24) between the first and second ends (16,18). Reactive element (30) includes a conductive element (32) disposed on a dielectric film (40), the conductive element (32) having a selected area and shape and extending to first and second ends (34,36) associated with the first and second selected windings (22,24). The reactive element (30) is at least partially wrapped around the coil (14) with the film (40) adjacent to the windings (20) and extending therealong at least between the first and second selected windings (22,24) such that the first and second ends (34,36) of the conductive element (32) are adjacent to and insulated from the first and second selected windings (22,24).

Abstract: The disclosure relates to an antenna device for radio communications apparatus operating in the frequency range of 800-3000 MHz and including a radiator. A dielectric resonator is connected to the supply line of the antenna device, the resonator being galvanically discrete from the radiator but being operative to supply it.

Abstract: A dual-notch loaded microstrip antenna has a single-medium substrate, a metal layer and a microstrip antenna layer, wherein the microstrip antenna layer of the microstrip antenna is etched into a double dual-notch or a single dual-notch structure. The microstrip antenna layer and the metal layer adhere respectively to opposite sides of the single-layer substrate, wherein the metal layer works as the electrical ground. The single-layer substrate contains a penetrating opening whose diameter and location are predetermined. The task of transmitting and receiving dual-band or multi-band signals is carried out by feeding the microstrip layer with signals from a connector, such as a coaxial connector, through the penetrating opening.

Abstract: A radio antenna is disclosed with improvement in a radiation efficiency obtained by changing a directivity pattern of an antenna toward a direction not interfered by an obstacle and thus reducing radio wave interference by the obstacle. A whip antenna is connected to a transceiver unit in a radio set housing through a feeder line. A passive element is grounded to the radio set housing through a load impedance element. The whip antenna changes the horizontal directivity pattern in dependence upon the electromagnetic coupling with the passive element. The passive element operates as a wave director or a reflector for the whip antenna in accordance with the value of the load impedance element. When the passive element operates as a wave director, the radiation becomes much stronger in the direction toward the passive element. On the other hand, when the passive element operates as a reflector, the radiation in the direction away from the passive element becomes much stronger.

Abstract: In one preferred embodiment, a dual band antenna having a radiating element which includes: a one-quarter PCS wavelength radiating portion which serves as a base; a one-half PCS wavelength radiating portion; a PCS phasing coil joining the one-quarter PCS wavelength radiating portion to the one-half PCS wavelength radiating portion, wherein the PCS phasing coil substantially allows energy in the AMPS band to pass therethrough; a one-half AMPS wavelength radiating portion; and an AMPS phasing coil joining the one-half AMPS wavelength radiating portion to the one-half PCS wavelength radiating portion, wherein the AMPS phasing coil substantially prevents energy in the PCS band from passing therethrough, and wherein the AMPS phasing coil provides a 180 degree phase shift for energy in the AMPS band.

Abstract: A self-resonant vertically polarized folded unipole antenna for long wave (LW), medium wave (MW) broadcasting and for the 160 meter amateur radio band with a grounded tower connected to radially descending fold wires terminated near the base of the tower in an open polygonal ring, possibly a C-ring with a reactive load in series with this ring. This reactance cancels the reactive component of the antenna input impedance causing the input impedance to appear resistive at the feed point. This leads to outstanding linearity and bandwidth up to and possibly exceeding plus or minus 16 kHz, sometimes exceeding plus and minus 20 kHz. The antenna is particularly useful for AM broadcasting of high quality music with response capable of being better than that of FM.

Abstract: A transponder (30), intended to exchange data during a half duplex communication, includes a coil (3), a capacitor (8) connected to the coil to form a resonant circuit, and processing means (33) arranged to process the data. The transponder further includes switching means (32) arranged so that, under the control of the processing means, the switching means connect the processing means in series with the capacitor and the coil which are connected to form, during the entire duration of the reception phase, a parallel LC circuit and, during the entire duration of the transmission phase, a series LC circuit to optimize the electric power exchanged between an antenna and the processing means.

Abstract: An AM/FM/CB/cellular telephone antenna includes a first frequency self-resonant circuit at a position above the lower end of the antenna such that the electrical length of the lower section of the antenna is equivalent to one-quarter wavelength for a frequency in the FM frequency range and a second frequency self-resonant circuit disposed below the first frequency self-resonant circuit. The first self-resonant circuit presents a high impedance in the FM frequency band and the second self-resonant circuit presents a high impedance in the cellular frequency range. The entire length of the antenna is equivalent to one-quarter wavelength in a frequency in the CB frequency band. The antenna wire is wound around a fiberglass core, and the FM self-resonant circuit is formed by a tightly wound, coiled section of the wire together with a thin-walled brass tube extending over the core in the area of the tightly wound section.

Abstract: An antenna with loading coil is described, which has an especially high Q for longer range communication. The inside of the coil is left empty of solid material while a frame that surrounds the coil is of dielectric material. The wire that forms the coil is constructed so upper and lower wire portions that extend radially inwardly from the ends of the coil, extend at inclines much greater than the wind angle of the coil, and hold metallic coupling slugs away from the opposite ends of the coil. Strips of silicone extend between adjacent coil turns and are mounted on the coil, to minimize vibrations while using a minimum of dielectric material close to the coil. By combining these improvements into a practical commercial coil, applicant has raised the coil Q by 29.5% from the Q of his previous antenna which had the highest Q of citizen band antennas on the market.

Abstract: A top-loaded, vertically polarized antenna (10) comprised of two ring radiators (108, 110) formed into loops to provide a dual resonant frequency antenna less than 8 inches on a side for use in the 130 to 150 MHz frequency band. By using separate transmit and receive elements, separate resonant frequencies can be provided without the use of lossy duplexers. The antenna can be concealed inside a housing also containing the radio equipment.

Abstract: An antenna apparatus for a communication device operating in the frequency range of between 800 and 3000 MHz, comprises at least one radiator (1), which is galvanically connected to one end of a spiral conductor (2). This is, in turn, connected to a transceiver (4). An earthed conductor (6) extends along the extent of the spiral (2) to form a capacitance therewith distributed along the spiral.

Abstract: An antenna arrangement of sufficiently small size to be accommodated in the housing of a portable communications device includes a pair of spaced folded monopole antennas. Each antenna includes a first printed circuit board having a conducting surface that forms a ground plane. Mounted on the first circuit board is a second printed circuit board having a right-angled strip of conducting material, which forms a folded monopole radiating element. The folding of the monopole reduces its height, to thereby enable it to fit into small casings and the like. To compensate for the effects of the folded monopole on the electrical match, frequency bandwidth and electromagnetic fields, a shunt inductance is introduced between the monopole and the ground plane. The antennas are mounted within cavities that can be lined or coated with metallic material, to improve the radiation patterns of the antennas and isolate them from the electronic components of the communications system.

Abstract: The invention relates to an antenna structure D with at least two resonance frequency bands. It comprises a first antenna element (P2; P3) which is preferably a straight conductor, and a second antenna element (HX3; HX4) which is preferably a conductor wound into a cylindrical coil, the antenna elements having different resonance frequencies. A rod element (P2; P3) is partly inside a helical element (HX3; HX4) and they can comprise the same feed point (A4) or separate feed points (A5; A6). The antenna can comprise a third antenna element (HX5) which is preferably a conductor wound into a cylindrical coil comprising a different resonance frequency from the other two antenna elements. The antenna according to the invention is well-adapted to be used in a mobile phone operating in at least two cellular telephone systems using different frequencies.

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 adapted for surface deployment is provided. A coaxial feedline, erminated at one end thereof at a feedpoint, has a center conductor and a shield at ground potential. A continuous length of antenna wire having first and second ends is electrically connected at its first end to the center conductor at the feedpoint. A first portion of the continuous length is spooled adjacent the first end. A second portion of the continuous length is deployed from the first portion by means of tension at the second end. The second portion extends to the second end along a substantially straight line away from the first portion. The second portion is typically at least as long as the first portion. The first portion serves as a variable tuning inductor for the antenna as the second portion is deployed therefrom.

Abstract: An antenna includes a dipole (20) with upper and lower elongated conductors (22, 24) and a feedline (40) for carrying radio frequency currents to the dipole by connecting the feedline to the lower end (30) of the upper conductor and to the upper end (32) of the lower conductor, which produces maximum gain. A spacer (50) spaces the center of the feedline by a distance (A) of about 3 centimeters from the center of the lower conductor, to produce minimum losses while providing a compact antenna. A toroidal ferrite core (110) lies at the bottom of the lower conductor and the feedline is in the form of a wire pair that is wrapped a plurality of times about the ferrite core to prevent signals radiated by the lower conductor and picked up by the feedline, from passing to the radio. A tuning member (150) of electrically conductive material can be slid along the spacer to tune the antenna without changing its height (B).