Abstract: An antenna element includes a balun configured to convert an unbalanced signal to a balanced signal and having an input, a first output, and a second output. The antenna element further includes a feed layer having a first feed coupled to the first output of the balun, a second feed coupled to the second output of the balun, a first ridge coupled to the first feed, a second ridge coupled to the second feed, and a center post.

Abstract: An antenna element comprises one or more directors, a resonator, and a three dimensional ground assembly. Parts of the antenna element are arranged on three metal layers. A top layer has an unconnected metal bar which forms a beam director, a resonator and a top part of the ground assembly. The resonator is an integral piece substantially in the form of a loop connected to a feed line and a feed line terminal ending. The feed line terminal ending serves as the ground plane for the feed line as well as providing impedance matching from the external transceiver circuit to the resonator. The ground assembly includes a top layer ground connected to a plurality of metallized half cylindrical hole channels (or metallized via holes) which connect to a ground terminal in a bottom layer.

Abstract: A dipole antenna includes a planar reflector and a radiating element. The radiating element includes first and second pairs of dipoles on a surface of the planar reflector. The first and second pairs of dipoles respectively include arm segments arranged around a central region in a box dipole arrangement. The arm segments may be printed circuit board portions having respective metal segments and respective inductor-capacitor circuits thereon. The inductor-capacitor circuits define a filter aligned to a frequency range higher than an operating frequency range of the first and second pairs of dipoles.

Abstract: A WIFI antenna, including: a dipole including a first radiator and a second radiator that are arranged opposite to and spaced apart from each other; a feeding port provided at adjacent ends of the first radiator and the second radiator; a balun structure including a first access portion, a second access portion provided opposite to the first access portion, and an intermediate portion connecting the first access portion with the second access portion, and the intermediate portion having an annular structure; the first access portion of the balun structure is connected to the first radiator at the feeding port, and the second access portion is connected to the second radiator at the feeding port. Setting of the WIFI antenna provides characteristics of omnidirectional radiation, high gain and high physical stability, which not only improves the gain, but also fully covers the WIFI frequency band.

Abstract: An electronic device is provided. The electronic device includes a metal housing, an insulation element, and an antenna unit. The insulation element is disposed on the metal housing and includes a first heat dissipation hole. The antenna unit is disposed on the insulation element and includes a radiation portion and a feeding portion. The radiation portion is composed of a conductor. The feeding portion is electrically connected to the radiation portion and a grounding plane. In this way, according to the electronic device, space configuration inside the electronic device is saved and a shielding effect of the metal housing is prevented from affecting stability of sending and receiving a signal.

Abstract: A microwave energy source that generates a microwave energy is disclosed. The microwave energy source has an on-state and an off-state. A control circuit is coupled to the microwave energy source and includes an output to generate a control signal that adjusts a pulse frequency of the microwave energy. A voltage generator applies a non-zero voltage to the microwave energy source during the off-state. A frequency and a duty cycle of the non-zero voltage is based on a frequency and a duty cycle of the control signal. A waveguide is coupled to the microwave energy source. The waveguide has a supply gas inlet that receives a supply gas, a reaction zone that generates a plasma, a process inlet that injects a raw material into the reaction zone, and an outlet that outputs a powder based on a mixture of the supply gas and the raw material within the plasma.

Abstract: An electronic device may be provided with an antenna for receiving signals in first and second ultra-wideband communications bands. The antenna may include a first arm that radiates in the first band and a second arm that radiates in the second band. The antenna may be fed by a stripline. A microstrip may couple the stripline to the first and second arms and may be configured to match the impedance of the stripline to the impedance of the first and second arms in the first and second bands, respectively. Sets of antennas tuned to different frequencies may be fed by the same transmission line and may collectively exhibit a relatively wide bandwidth. A conductive shielding layer or other conductive components may be layered over the antennas to mitigate cross-polarization interference at the antennas.

Abstract: Pulsed radiation is generated at a power level that depends on a voltage level, frequency and duty cycle of a pulsed high voltage. A pulsing switch generates the pulsed high voltage from a high voltage and a pulse control signal. The pulsing switch has first and second bi-polar active switches connected in series between a high voltage conductor and a ground conductor. The pulsed high voltage is produced at a connection between the first and second bi-polar active switches when the first and second bi-polar active switches are repeatedly pulsed on and off to alternatingly connect the high voltage conductor and the ground conductor to a pulsed voltage output.

Abstract: A broadband stacked multi-spiral antenna array comprising two or more spiral antennas with a dielectric layer having a generally uniform thickness positioned between each pair of stacked antennas, which are all center-fed and in-phase. The antenna array may be embedded in a non-conductive material, such as fiberglass embedded in a resin, a honeycomb core sandwich, or structural foam, that may be used to form a structural element of a mobile platform. The structural element may include a via providing a pathway for coaxial cables. If two structural elements are hatch covers on the port and the starboard sides of an aircraft, the use of a stacked multi-spiral antenna array in each structural element provides two roughly hemispherical coverage patterns which together provide an omni-directional coverage pattern. The stacked multi-spiral antenna array may also include a reflecting cavity placed at the bottom of one of the spiral antennas.

Abstract: A balanced wideband impedance transformer can include a first conductor layer including a first metal line and a second metal line, a second conductor layer including a first feed line and disposed on the first conductor layer, a third conductor layer including a second feed line and disposed on the second conductor layer, and a fourth conductor layer including a third metal line and a fourth metal line, and disposed on the third conductor layer.

Abstract: A circular dipole antenna (e.g., for a magnetic imaging system) according to exemplary embodiments of the present disclosure can comprise a circular conductor with a feed point on one side and a gap on the other. A surface coil loop antenna (e.g., for magnetic imaging system) is provided with a capacitor arrangement selected for non-uniform or unbalanced current distribution, with corresponding magnetic and electric dipole fields provided in a single structure referred to as a loopole.

Abstract: A disclosed antenna device includes a substrate made of a dielectric material, an antenna element formed on one side of the substrate, and a ground element formed on another side of the substrate.

Abstract: The planar antenna has a dielectric substrate; an antenna main body portion including first and second antenna elements on first and second sides, respectively, of the dielectric substrate and functioning as a balanced antenna; a signal line portion including first and second feed lines on the first and second sides, respectively, and a coplanar line on the first side and formed by a signal line and the first ground conductors, the signal line connected to the first feed line; a second ground conductor on the second side and connected to the second feed line; and via holes connecting the first ground conductors to the second ground conductor provided at ends of edges of the first ground conductors facing the end of the signal line where the signal line connects to the first feed line, to allow the first and second feed lines to function as balanced transmission lines.

Abstract: Antenna elements are described that may include a radiator, a feeding portion, a first impedance transformer, a balun, and a second impedance transformer. The first impedance transformer, balun, and second impedance transformer may be disposed above a ground plane of an antenna array to reduce a bulk of the array. The array can also include a dielectric top layer for loading apertures of the antenna array. The antenna elements can also include anomaly suppressors can be provided to cancel common-mode resonances from the radiators.

Abstract: Embodiments of the present invention disclose a dipole antenna and a wireless terminal device, which relate to communications technologies and enable an antenna to have a relatively high performance and a relatively low production cost. The dipole antenna includes a first radiation arm, a second radiation arm, and a balun. The first radiation arm and the second radiation arm are both soldered on a dielectric substrate. The first radiation arm and the second radiation arm are separately connected to the balun electrically. The balun is electrically connected to a feeding point and a reference ground separately. The present invention may be applied to a terminal device.

Abstract: A dipole antenna is disclosed. The dipole antenna includes a feed-in terminal, a balun, a first radiator and a second radiator. The feed-in terminal is used for feeding in a radio-frequency signal. The balun is electrically connected to the feed-in terminal for driving out a return current of the dipole antenna to balance a feed-in impedance of the dipole antenna. The first radiator is electrically connected to the feed-in terminal and the balun for radiating the radio-frequency signal in a first frequency band. The second radiator is electrically connected to the first radiator, the feed-in terminal and the balun for radiating the radio-frequency signal in a second frequency band.

Abstract: A broadband dipole antenna is provided, in which a radiator includes a plurality of radiation pattern units for transmitting and receiving a radio signal, the radiation pattern units have radiation patterns of resonators formed thereon, and a power supply and balun structure supports and supplies power to the radiator. Each of the plurality of radiation pattern units of the radiator has at least a dual radiation pattern structure having an inner radiation pattern and an outer radiation pattern.

Abstract: A broadband radiation unit includes first and second pairs of symmetric dipoles operable to transmit communication signals and to receive communication signals. The first pair of symmetric dipoles has a polarization that is orthogonal to that of the second pair of symmetric dipoles. The first and second pairs of symmetric dipoles together define an annular structure. A plurality of baluns are associated with the first and second pairs of symmetric dipoles such that a given one of the baluns is associated with a respective symmetric dipole of the pairs of symmetric dipoles. Each one of the baluns feeds a balanced current to its associated symmetric dipole. Each symmetric dipole of the first and second pairs of symmetric dipoles has two unit arms which are disposed on and arranged symmetrically about its associated balun.

Abstract: A wideband antenna with backlobe elimination in a confined space is disclosed. Backlobe elimination is by an array of electromagnetically conductive members disposed between the spiral element and the ground plane and almost contacting the ground plane so as to bleed a backlobe away from the spiral antenna to the ground plane. In one embodiment, the members are conical elements disposed between the spiral element and the ground plane of a spiral antenna such that the apexes of the conical elements almost contact the spiral element and the bases of the conical elements contact the ground plane. In some embodiments, other means may be employed to perform this function. In operation, conical elements bleed the backlobe of the signal away from the spiral element to the ground plane.

Abstract: An antenna apparatus that has a base and an antenna element with a balanced RF output, which receives RF signals within a first band of frequencies. The apparatus includes a mount engaged with the base that rotatably supports the antenna about an axis of rotation. The apparatus has a balun with a balanced RF input and an unbalanced RF output. A feed line is coupled between the balanced RF output and the balanced RF input. The feed line includes two electrical conductors that have a predetermined length and that are aligned substantially in parallel, and supportively spaced apart a predetermined distance by plural insulators. The feed line is further arranged to maintain the predetermined distance between the two electrical conductors as the antenna element rotates with respect to the base.

Abstract: A dipole antenna is disclosed. The dipole antenna includes a feed-in terminal, a balun, a first radiator and a second radiator. The feed-in terminal is used for feeding in a radio-frequency signal. The balun is electrically connected to the feed-in terminal for driving out a return current of the dipole antenna to balance a feed-in impedance of the dipole antenna. The first radiator is electrically connected to the feed-in terminal and the balun for radiating the radio-frequency signal in a first frequency band. The second radiator is electrically connected to the first radiator, the feed-in terminal and the balun for radiating the radio-frequency signal in a second frequency band.

Abstract: The height of crossed-dipoles antenna elements can be reduced by including an additional bend/segment in the feed-line and/or tuning-stub of the antenna dipole having the upper slot. The extra bend allows the crossed-dipoles antenna element to be shortened by as much as twenty percent without reducing the feed-line length. Additionally, the height of crossed-dipoles antenna elements can be reduced by shaping a winged portion of the balun-fed dipoles to match the contour of a radome contour, which allows the crossed-dipoles antenna element to accommodate a shallower radome and achieve a thinner antenna module. Additionally, the height of crossed-dipoles antenna elements can be reduced by positioning periodic structures around the base of low-band radiating elements to provide artificial magnetic conductor (AMC) functionality, which enables constructive interference between reflected and non-reflected signals at profile spacings of less than one-quarter wavelength.

Abstract: Provided herein are devices, systems and techniques for establishing a variable height conformal antenna array having a planar backplane. More particularly, positioning of radiating elements can be made insensitive to variable ground height by selecting a suitable radiating element, such as a flared notch and arranging them to have a profile such that their outer extremities are positioned along a conformal, curved shape. Differences in radiator heights can be taken up by the addition of parallel vertical ground planes disposed between the radiating elements and the backplane. Adjacent vertical ground planes effectively form cutoff waveguide sections that naturally isolate the backplane from the radiating elements. The vertical ground planes edges effectively form a virtual curved ground for the radiating elements, following curvature of the array profile. Accordingly, heights of radiating elements are uniform with respect to the virtual ground, while being allowed to vary with respect to the backplane.

Abstract: A polymorphic antenna, including a metallic template configurable in at least first and second possible different three-dimensional shapes, the antenna, when configured in the at least first and second different three-dimensional shapes, having a common antenna feed point, a common balun coupled to the common antenna feed point; and a common dipole coupled to the common antenna feed point and to the common balun. The antenna operates in a common frequency band when configured in either of the at least first and second different three-dimensional shapes when fed via the common antenna feed point.

Abstract: This document describes designs and techniques for directly feeding an unbalanced transmission line with a balanced antenna using Composite Right and Left Handed (CRLH) and balun structures. According to various examples, first and second radiating elements, first and second antenna structures, or first and second portions of an antenna structure can provide a left-handed (LH) mode resonance and a right-handed (RH) mode resonance. A feed port can provide an unbalanced signal, and a balun structure can be coupled to the first and second radiating elements, first and second antenna structures, or first and second portions of an antenna structure, to adapt the unbalanced signal from the feed port to a balanced signal for coupling to the first and second radiating elements, first and second antenna structures, or first and second portions of an antenna structure.

Abstract: An integrated differential high power amplifier-radiator array that overcomes the prior art impedance match issues is described. An impedance matching balun is used to feed a high output impedance, differential HPA, which in turn drives a wide band radiator or array of radiators having a matching input impedance to provide a highly efficient, compact transmit system. In one exemplary embodiment, the HPA may be a high impedance Class-B HPA configured as a push-pull cascode amplifier. A high impedance isolator or circulator may be used between the HPA and the radiator. One of ordinary skill in the art will readily appreciate that a receive implementation, using a properly matched low noise amplifier in place of the HPA, is also possible. Similarly, with the addition of a slotline circulator, transceiver operation is also attainable with the addition of an impedance matched receive chain.

Abstract: The invention relates to a balanced antenna system comprising a radiator connected via a matching circuit to a balun. In certain embodiments, the radiator comprises a first radiating element and a second radiating element and the matching circuit comprises a first impedance-matching circuit connected to the first radiating element and a second impedance-matching circuit connected to the second radiating element. The first and second matching circuits may be identical and are connected through the balun to a single port. To minimise the component count, the design of the matching circuit and balun is co-optimised.

Abstract: A polymorphic antenna, including a metallic template configurable in at least first and second possible different three-dimensional shapes, the antenna, when configured in the at least first and second different three-dimensional shapes, having a common antenna feed point, a common balun coupled to the common antenna feed point; and a common dipole coupled to the common antenna feed point and to the common balun. The antenna operates in a common frequency band when configured in either of the at least first and second different three-dimensional shapes when fed via the common antenna feed point.

Abstract: A wideband dual-polarized radiation element includes two pairs of cross polarized dipoles and baluns which correspondingly feed current to each dipole in a balanced manner. Each dipole includes a pair of unit arms aligned on a top end of the corresponding balun. One end of each unit arm is connected on top of the balun, and the other end of one unit arm is bending inwards to form inward loaded line, and the other unit arm is bending downwards to form downward loaded line. An antenna includes a metal reflector and at least one wideband dual polarized radiation element, which has excellent radiation and polarization performance.

Abstract: An antenna apparatus that can be miniaturized without causing inference caused by antenna currents to be occurred if the high band of a dual band wireless system is close to the band of another wireless system in a wireless communication apparatus incorporating the dual band wireless system and another wireless system is provided. A first switch 5 blocks passage of a signal of a high band (first frequency) and allows passage of a signal of a low band (second frequency). A second switch 6 blocks passage of a signal of the low band (second frequency) and allows passage of a signal of the high band (first frequency). Accordingly, the antenna apparatus operates as a dipole antenna with no antenna current flowing into a feeder line at the first frequency and operates as a monopole antenna wherein a radiation element and a feeder line making up the dipole antenna becomes a radiation element at the second frequency lower than the first frequency.

Abstract: An antenna module having a side-edge balance-to-unbalance (BALUN). The antenna module may include a flexible substrate with one or more layers that may be configured to receive one first and second conductive patterns, the substrate may have opposed first and second ends which may define a longitudinal length and/or opposed side edges situated between the first and second ends. The first conductive pattern may form an antenna loop situated adjacent to the first end of the flexible substrate and be suitable for transmitting or receiving signals at one or more frequencies. The second conductive pattern may form at least part of the BALUN and may include one or more of a center portion, side portions which may extend from the center portion at opposite sides of the center portion, and electrically neutral slots situated between a corresponding side portion and the center portion.

Abstract: An antenna structure includes first and second antennas. The first antenna has a first geometry corresponding to a first frequency. The second antenna has a second geometry corresponding to a second frequency. The second antenna is proximal to the first antenna and utilizes electrical-magnetic properties of the first antenna to transceive signals at the second frequency.

Abstract: A double balun dipole antenna element includes a dielectric substrate having a first surface and an opposing second surface, a pair of coplanar Marchand baluns positioned in a mutually antiphase configuration on the first and second surfaces, and at least one feed line connected to the pair of Marchand baluns. A doubly polarized antenna element includes a pair of orthogonally interleaved double balun dipole antenna elements, which can be further configured into an array of such antenna elements.

Abstract: A polymorphic antenna, including a metallic template configurable in at least first and second possible different three-dimensional shapes, the antenna, when configured in the at least first and second different three-dimensional shapes, having a common antenna feed point, a common balun coupled to the common antenna feed point; and a common dipole coupled to the common antenna feed point and to the common balun. The antenna operates in a common frequency band when configured in either of the at least first and second different three-dimensional shapes when fed via the common antenna feed point.

Abstract: Aspects of a method and system for matching an integrated system to an antenna utilizing on-chip measurement of reflected signals are provided. In a chip comprising at least a portion of a receiver and at least a portion of a transmitter, a best impedance match between an antenna and the chip may be determined based on on-chip measurement of one or more signals reflected from the antenna. The best impedance match between the antenna and the chip may be determined utilizing a correction algorithm. The correction algorithm may be determined utilizing data from an external test set that measures signals transmitted by the chip via the antenna. The reflected signals may be routed to a signal analyzer via on on-chip directional coupler. The best impedance match may be determined for each of a plurality of frequencies and/or each of a plurality of transmit signal strengths.

Abstract: A broadband antenna system is disclosed. The antenna system relates to a modified conical structure, wherein the feed region of the cone is cut away to form a hollow “coneless” cylinder, and the distribution of one or more tapered feed points around the circumference of the cylinder allows a plurality of feed lines, cables, piping, or other structures to be run through the center of the antenna without interfering with the performance of the antenna system. The invention further relates to a stacked broadband antenna system wherein additional coneless elements, as well as other types of antennas or devices, may be stacked collinearly on, or disposed coaxially to, the cylindrical antenna structure, and fed, powered or operated via the plurality of feed lines, cables, piping or other structures. The overall system may thus provide a wide range of transmitting, receiving, sensing and other capabilities.

Abstract: A polymorphic antenna, including a metallic template configurable in at least first and second possible different three-dimensional shapes, the antenna, when configured in the at least first and second different three-dimensional shapes, having a common antenna feed point, a common balun coupled to the common antenna feed point; and a common dipole coupled to the common antenna feed point and to the common balun. The antenna operates in a common frequency band when configured in either of the at least first and second different three-dimensional shapes when fed via the common antenna feed point.

Abstract: A balanced dipole antenna, comprising: a left dipole arm having a center end, a right dipole arm having a center end, a coaxial cable having an outer conductor and a single inner conductor and a top end electrically located between the center ends of the left and right dipole arms, a left stub coupling the left dipole arm and the coaxial cable, and a right stub coupling the right dipole arm and the coaxial cable, wherein the inner conductor of the coaxial cable is connected to one of the left and right dipole arms, and the outer conductor of the coaxial cable is connected to the other of the left and right dipole arms.

Abstract: A CPW fed planar log-periodic antenna is provided. The antenna includes: an upper substrate; a planar log-periodic antenna structure formed beneath the upper substrate; a CPW-fed structure formed on the upper substrate for feeding energy into the planar log-periodic antenna structure; a lower substrate disposed beneath the upper substrate; and a wire structure formed beneath the lower substrate. The antenna of the present invention features efficient reduction of cross polarized radiation and thereby enhancing the performance.

Abstract: A feed module is provided for an array antenna. The feed module comprises a multi-layer printed circuit board (PCB) feed structure for coupling signals between connections to transmitters or receivers and connection points for connecting to antenna elements of the array antenna. The multi-layer PCB feed structure comprises a body portion, incorporating coupling components, and a number of line sections for connecting to elements of the array antenna. The planar layers of the multi-layer PCB are arranged to be mounted substantially perpendicular to a planar array of antenna elements of the array antenna when the feed module is integrated therewith.

Abstract: A device for transmitting and/or receiving electromagnetic RF signals, in particular a UWB antenna, has a planar, ultra-wideband antenna structure made of a plurality of dipole elements. Each dipole element comprises two poles having substantially elliptical base shapes. A measuring machine, in particular a locating and/or material identifying device for identifying objects encased in a medium and/or for identifying material parameters, in particular the moisture of a material, has at least one UWB sensor comprising at least one device for transmitting electromagnetic RF signals. A machine tool monitoring device has a detecting device for detecting the presence of a material type, in particular of tissue, in a machine tool working area, and has a working mechanism wherein the detecting device comprises a sensor unit having at least one device for transmitting electromagnetic RF signals.

Abstract: An antenna element and balun are described. The antenna includes a plurality of droopy bowtie antenna elements disposed on dielectric block and a feed point. The balun includes a central member having dielectric slabs symmetrically disposed on external surfaces thereof. At least one end of the balun is provided having a shape such that conductors on the dielectric slabs of the balun can be coupled to the the droopy bowtie antenna elements.

Abstract: Disclosed is a tapered double balun for use with rotationally-symmetrical, frequency-independent antennas that are fed using spiral-mode number 2. The tapered double balun may be used to provide a four-terminal line, where all terminals carry the same voltage, but adjacent terminals are out of phase and opposite terminals are in phase. The antennas may be spirals, sinuous, or other four-arm antennas. The tapered double balun is a stripline device comprising two outer ground planes and a center conductor that is dielectrically separated from the ground planes. The outer ground planes each taper from a wide dimension at the connector end of the device to a narrow dimension at the antenna end of the device. The narrow opposing strips comprising the ground planes are configured to connect to two opposed arms of the antenna.

Abstract: Aspects of a method and system for matching an integrated FM system to an antenna utilizing on-chip measurement of reflected signals are provided. In this regard a portion of a signal output by an integrated FM radio transmit block and reflected by an antenna may be routed to an on-chip signal analyzer. Accordingly, measurements of the reflected signals may be utilized to configure a matching network in order to provide a best impedance match between the FM radio and the antenna. In this regard, a best impedance match may maximize radiation efficiency and/or radiated power. Additionally, the configuration of the matching network may incorporate a correction algorithm/offset experimentally determined via a calibration utilizing external components.

Abstract: This document describes designs and techniques for directly feeding an unbalanced transmission line with a balanced antenna using Composite Right and Left Handed (CRLH) and balun structures.

Abstract: An antenna structure includes first and second antennas. The first antenna has a first geometry corresponding to a first frequency. The second antenna has a second geometry corresponding to a second frequency. The second antenna is proximal to the first antenna and utilizes electrical-magnetic properties of the first antenna to transceive signals at the second frequency.

Abstract: The present invention provides a compact antenna system having multiple antennas exhibiting polarization and pattern diversity. The system comprises at least two antennas which may have different polarizations, operatively coupled to a passive element which operates as a Balun for a first antenna and which is configured to absorb and re-radiate electromagnetic radiation from the second antenna to produce a desired radiation pattern. The present invention also provides for additional antennas operatively coupled to the passive element or to the first antenna to provide additional diversity.

Abstract: A transmission line balun comprising a tubular ferrite having a longitudinal passageway concentrically positioned over a conductive sleeve having a longitudinal passageway. The end of a coax feeder is positioned in the longitudinal passageway of the sleeve and the sleeve is grounded at its proximal end to the shield of the coax cable. The sleeve buffers the effects of the parasitic line caused by using ferrite in a balun.

Abstract: An antenna is provided for GNSS and other applications and includes an adjustable-height vertical support PCB mounted on a ground plane and mounting a crossed-dipole radiating arm element assembly. The gain pattern of the antenna can be varied by constructing the vertical support PCB with different heights or adjusting the height and gain pattern in the field. Vehicles with significant pitch and roll can be provided with low-horizon tracking capability by providing a high-profile antenna configuration. Alternatively, low-profile configurations provide steeper gain pattern rolloff at the horizon for maximal multipath rejection and high accuracy. The droop angles of the radiating arm elements are also adjustable for varying the gain pattern and beamwidth. A matching and phasing network is connected to the radiating arm elements and provides a relatively constant input impedance for the various antenna configurations.

Abstract: An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed therein that enables the antenna to be used over a wide range of frequencies. The element is made of two longitudinally aligned, hollow support arms made of non-conductive material. Disposed longitudinally inside each element is a length adjustable conductive member electrically connected at one end. In the preferred embodiment, each conductive member is stored on a spool that is selectively rotated to precisely extend the conductive member into the support arm. The support arms, which may be fixed or adjustable in length, are affixed at one end to a rigid housing. During use, the conductive members are adjusted in length to tune the element to a desired frequency.