Abstract: An antenna comprises first and second radiating elements for connecting to a first and second potential levels respectively. The first and second potential levels are substantially different for generating an electrostatic field from the first and the second radiating elements. The antenna further comprises first and second field shaping structures for controlling field propagation in a first and second direction respectively. The first and second field shaping structures are interdisplaced for defining a field pathway while the first and second radiating elements are disposed adjacent to the first and second field shaping structures and along the field pathway for directing the electrostatic field in a propagation direction through a liquid medium. More specifically, the propagation direction is defined by the field pathway and substantially perpendicular to at least one of the first and second directions.

Abstract: A wireless local area network (“WLAN”) antenna array (“WLANAA”) is disclosed. The WLANAA may include a circular housing having a plurality of radial sectors and a plurality of primary antenna elements. Each individual primary antenna element of the plurality of primary antenna elements may be positioned within an individual radial sector of the plurality of radial sectors.

Abstract: A dual polarized variable beam tilt antenna having a superior Sector Power Ratio (SPR). The antenna may have slant 45 degree dipole radiating elements including directors, and may be disposed on a plurality of tilted element trays to orient an antenna boresight downtilt. The directors may be disposed above or about the respective dipole radiating elements. The antenna has a beam front-to-side ratio exceeding 20 dB, a horizontal beam front-to-back ratio exceeding 40 dB, a high-roll off, and is operable over an expanded frequency range.

Abstract: A portable Yagi antenna kit for being frequency/wavelength adjustable by virtue of being knockdownable, wherein the Yagi antenna is for mounting to a mast. The antenna includes a boom, a reflector element, a driven element, and a director element. The reflector element, the driven element, and the director element each extend outwardly from the boom, respectively. The boom, the reflector element, the driven element, and the director element are each knockdownable so as to be portable and form the kit, and as such, are length adjustable, and as such, are frequency/wavelength adjustable.

Abstract: The utilization of small antennas for mobile devices and for low frequency (long wavelength) applications is desired. Further, efficient use of transmission power is desirable, especially in mobile applications. For this purpose, a system is provided that includes one or more of: a multiple-resonator transmitter/receiver, a high bandwidth electrically small antenna, a resonator with a variable feed location, a resonator with a variable reactive component load, and a method for estimating a resonator system response to a component configuration and selected excitation.

Abstract: An aftermarket UHF parasitic antenna kit and method for a mobile television antenna includes: a base having an engagement surface and an extending boom; rivet holes in the engagement surface that correspond in size and location to a corresponding number of holes in the bottom of the mobile television antenna; push rivets that engage the rivet and bottom holes to hold the base to the bottom of the mobile television antenna; base foot holes in the engagement surface and boom; resilient base feet that engage the base foot holes; and at least one parasitic antenna element connected to the boom.

Abstract: A tire air pressure monitoring system has a plurality of sensor units and a receiver. The pressure sensor units are mounted near corresponding tires to measure tire air pressures and transmit transmission signals indicating the respective measured tire air pressures. The receiver has an antenna element, a variable capacitor and a power supply source. The variable capacitor is coupled to the antenna element. The power supply source supplies electric power to the antenna element. The voltage supplied to the variable capacitor is controlled so that a current flowing in the antenna element is changed and its directivity is changed. Thus, the transmission signals will be received more surely.

Abstract: A printed dual-band Yagi-Uda antenna is disclosed, which includes a substrate, a first driver, a first director, a second driver and a reflector. The first driver is formed on the substrate, and is utilized for generating a radiation pattern of a first frequency band. The first director is formed at a side of the first driver on the substrate, and is utilized for directing the radiation pattern of the first frequency band toward a first direction. The second driver is formed between the first driver and the first director on the substrate, and is utilized for generating a radiation pattern of a second frequency band. The reflector is formed at another side of the first driver on the substrate, and is utilized for reflecting both the radiation patterns of the first frequency band and the second frequency band toward the first direction.

Abstract: A RFID tag or label comprises a RFID tag module (comprising an electronic identification circuit and a coupling means) and an antenna structure coupled to the coupling means. The RFID tag module is separate from, separable or arranged to be severable from, the antenna structure. The tag module can be placed in or on an object and the antenna structure in or on packaging material for use with the object. A patch antenna type RFID tag antenna structure has a ground plane spaced from the patch antenna so as to increase the range of the tag. The ground plane is not substantially larger than, and electrically insulated from, the patch antenna. The ground plane is flexible, so the RFID tag structure can be worn by a human, and can be incorporated into a piece of clothing. A RFID antenna structure for use with a tag reader is made flat and robust so that it can be mounted on the ground to be walked upon or driven over.

Abstract: An antenna comprising an IMD element, and one or more parasitic and active tuning elements is disclosed. The IMD element, when used in combination with the active tuning and parasitic elements, allows antenna operation at multiple resonant frequencies. In addition, the direction of antenna radiation pattern may be arbitrarily rotated in accordance with the parasitic and active tuning elements.

Abstract: A portable Yagi antenna kit for being frequency/wavelength adjustable by virtue of being knockdownable, wherein the Yagi antenna is for mounting to a mast. The antenna includes a boom, a reflector element, a driven element, and a director element. The reflector element, the driven element, and the director element each extend outwardly from the boom, respectively. The boom, the reflector element, the driven element, and the director element are each knockdownable so as to be portable and form the kit, and as such, are length adjustable, and as such, are frequency/wavelength adjustable.

Abstract: The present invention relates to an antenna arrangement connectable to a transceiver for transmitting and receiving RF signals in at least two separate frequency bands. The antenna arrangement has at least two sets of antenna elements arranged on a reflector, and the antenna elements are arranged in an interleaved configuration along a single column. The two separate frequency bands are substantially non-overlapping but relatively close to each other, and the distance between adjacent antenna elements in said column is substantially the same along the column.

Abstract: There is provided an antenna arrangement for use in an ultra-wideband network, the antenna arrangement comprising an active element; and a plurality of passive elements arranged around the active element; each passive element being controllable to selectively reflect or transmit radio signals emitted by the active element so as to create a desired beam pattern from the active element.

Abstract: Systems and methods for communicating over multiple frequency bands include a driven antenna element and a parasitic element communicatively coupled to the driven antenna element, the parasitic element including at least a first and a second conductive section. The parasitic element can include two or more conductive sections, and the sections can be coupled using a connector (e.g., switching element or trap). Further, some driven antenna elements may be associated with two or more parasitic elements.

Abstract: An antenna comprising a reflective surface; and an array of dipole antenna elements disposed adjacent to the reflective surface. Each antenna element has a pair of arms which together define a dipole axis, and the dipole axis is tilted at an acute angle with respect to the reflective surface. The pair of arms may be dipole arms, or may be Yagi director arms. In some embodiments the dipole axis is tilted at an acute angle with respect to a feed axis. In some embodiments the antenna element comprises a feed portion defining a feed axis; and the feed portion has a mounting portion which is tilted at an acute angle with respect to the feed axis.

Abstract: An antenna array system includes a launcher comprising an antenna configured to establish and steer a wavefront, and an array of Yagi-Uda director trains coupled to the launcher and located in the path of the wavefront. The array of Yagi-Uda director trains is configured to influence a beamwidth of the launcher. A method for beam steering includes launching a wavefront generated by an antenna through an array of director elements, and steering the wavefront. The array of director elements focuses the wavefront and influences gain of the antenna over plural steering angles.

Abstract: An open Yaggi antenna array is disclosed wherein the reflector element and parasitic director elements of the antenna array are opened in line with the feed point of the driven element so that the reflector and director elements do not cause a shunting effect on the driven element of the antenna.

Abstract: An antenna array has a ground plane, a plurality of spacers, a radiating patch array and a feeding member. The spacers are mounted on the ground plane. The radiating patch array is mounted on the spacers, is separated from the ground plane at an interval and has three pairs of radiating patches. Each radiating patch is parallel to the ground plane and has a sub radiating patch formed on and inclined away from the ground plane. The inclined sub radiating patches and the interval increase gain of the antenna array.

Abstract: A radio frequency identification device including a substantially planar surface. Surface has a longitudinal axis and lateral axis. A plurality of discrete longitudinally spaced laterally elongate conductive dipole elements is mounted to surface. In the present embodiment these elements include a director element, a reflector element, and a driven element that is positioned intermediate of the director element and the reflector element. A radio frequency identification chip is conductively attached to driven element.

Abstract: The polarization-diverse antenna array includes three orthogonal loop antennas having a common center, e.g. together defining a sphere. Each loop antenna includes a loop electrical conductor. Two signal feedpoints are along the loop electrical conductor and separated by a fraction of a length of the loop electrical conductor. Each of the signal feedpoints includes a series signal feedpoint so that a polarization diversity controller coupled thereto may selectively provide vertical, horizontal, lefthand circular and righthand circular polarization for a single loop electrical conductor, including simultaneous (dual) polarizations. These signal feedpoints may supply signals with vertical, horizontal, lefthand circular and righthand circular polarization from each of the three orthogonal look-angles provided by the three loop electrical conductors.

Abstract: An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed. 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. Each conductive member is stored on a spool that is selectively rotated to extend the conductive member into the support arm. The support arms 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. The antenna can be optimally tuned at a specific frequency for maximum gain, maximum front-to-back ratio, as a bi-directional antenna, and to provide a desired feed point impedance. An electronic control system allows the length of the conductive members to be manually or automatically adjusted to a desired frequency.

Abstract: A method for forming an array antenna beam of a mobile terminal periodically compares transmit/receive characteristics of a three-dimensional adaptive beam with transmit/receive characteristics of an omnidirectional beam periodically. A beam direction having better transmit/receive characteristics is then selected. By horizontally rotating an array antenna beam toward up or down at an angle of 360° degrees, a direction having a maximum signal receiving value is searched, and a three-dimensional adaptive beam is set in the searched direction. By using position information of a mobile terminal together with the detected information, a beam direction is set. And, by comparing beam direction information set toward a maximum signal receiving direction with beam direction information set on the basis of position information of a base station/mobile terminal, an optimum beam is selected and formed, thereby improving transmit/receive characteristics of the mobile terminal.

Abstract: A center fed half-wave dipole antenna system includes first and second end brackets that are separated by a center bracket. The center bracket and each of the end brackets include a plurality of electrically isolated terminals allowing the center bracket to be coupled to each of the end brackets via a pair of dipole lines that may contain multiple dipole wires. As such, the antenna system is able to increase the effective length of the dipole antenna in a reduced amount of space, thus reducing the mounting area requirements of the antenna system.

Abstract: The method and apparatus described herein improves the bandwidth of a selected frequency band of a multi-band antenna. In particular, a selection circuit selectively applies capacitive coupling to the multi-band antenna to improve the bandwidth of a first frequency band without adversely affecting the bandwidth of a second frequency band. To that end, the multi-band antenna of the present invention comprises a main antenna element and a parasitic element disposed proximate the main antenna element. When the multi-band antenna operates in the first frequency band, the main antenna element capacitively couples to the parasitic element. However, when the multi-band antenna operates in the second frequency band, the selection circuit disables the capacitive coupling.

Abstract: An antenna array includes an upper antenna and a lower antenna. Each antenna includes a driver dipole element and a director element horizontally spaced apart approximately one eighth wavelength from the driver dipole element. The driver dipole element is preferably approximately one half wavelength in overall length and the director element is preferably one half wavelength in length. The upper antenna is vertically spaced above the ground by approximately one wavelength and the upper and lower antennas are vertically spaced approximately one half wavelength apart. A preferred use of the antenna array is as an amateur radio antenna and a preferred frequency band is 14.0 to 14.350 MHZ corresponding to an approximately 20 meter wavelength.

Abstract: An adjustable-frequency two-element bowtie antenna includes a support member on which first and second non-conductive hollow element support arms are mounted. Each support arm includes first and second opposing segments. The first and second segments of each element support arm include a first section extending outwardly from the support member, a curved transition section, and a second section extending in a direction towards and joining the second section of the other element support arm. The spacing between the first sections of each segment of each element support arm increase as a function of the distance from the support member. A length-adjustable conductive member is disposed in each element support arm. Length adjusters are coupled to the conductive members to configure the lengths of antenna elements. A connector may be provided to couple a transmission-line to a pair of the conductive members comprising a driven element.

Abstract: An antenna system comprises a parasitic element, which is an electrically tuned structural element, installed between antennas to reduce or eliminate antenna-to-antenna coupled electromagnetic interference by emitting destructive interference in the direction from one antenna to another antenna. The antenna system comprises a first antenna operating at a first wavelength, a second antenna operating at a second wavelength, and a parasitic element located between the first antenna and the second antenna for reducing the amplitude of signals from the first antenna that would otherwise create electromagnetic interference in a receiver connected to the second antenna. The parasitic element is typically spaced from the first antenna by a distance substantially equal to one quarter of the first wavelength. The parasitic element generally has a height that is greater than the height of the first antenna.

Abstract: An antenna device includes a first elliptic reflective surface, a first antenna and a second antenna. The first elliptic reflective surface has a first focus and a second focus. The first antenna is disposed on the first focus, and the second antenna is disposed on the second focus. The first antenna transmits a first signal and a second signal, and the second antenna receives the first signal and the second signal. The first signal is transmitted directly to the second antenna from the first antenna. The second signal is reflected by the first elliptic reflective surface and transmitted to the second antenna.

Abstract: An antenna (11) includes a patch antenna element (22) capacitively coupled to a load patch (27). A switch (33) connects the load patch (27) to one of one or more strip lines (35, 37, 40), each of which has a different length. Each strip lines causes the load patch (27) to have a different impedance, with one causing a short circuit, one causing an open circuit, and one causing an impedance in between these extremes. Different impedances of the load patch (27) cause different frequencies of operation of the antenna patch (22) by virtue of the capacitive coupling therebetween. The antenna (11) is thereby tuneable to three separate frequencies. Other frequency bands are unaffected by virtue of the location of the load patch (27) relative to the antenna patch (22). By allowing tuning by way of controlling the impedance of the load patch (27), the antenna arrangement can be made smaller than a corresponding passive antenna operable at the same frequencies.

Abstract: An impedance matching means according to the present invention is used with an antenna and is realized by a parasitic element (3) for tuning an impedance of the antenna. The antenna comprises a grounding plate (2), an radiating body (1) arranged on the grounding plate (2) and a transmission line (4) coupled to said radiating body (1) and grounding plate (2). The parasitic element (3) formed of a narrow metal sheet and configured as a bridge shape is arranged on the grounding plate (2). The parasitic element (3) has a first and a second ends (311, 321), both of which are electrically connected to the grounding plate (2). The arrangement of the parasitic element (3) results in a change of the impedance of the antenna, so the impedance matching between the antenna and the transmission line (4) can be achieved.

Abstract: A stacked patch antenna including a distributed reactive network proximity feed, preferably implemented in a microstrip metallization network, coupled to an active antenna patch element to feed the active antenna patch element to emit a field to parasitically stimulate a parasitic antenna patch element.

Abstract: An RF transponder comprises a transponder integrated circuit, an antenna connected to the transponder integrated circuit, and at least one parasitic element adapted to interact electrically with the antenna and thereby affect antenna impedance. The orientation of the parasitic element with respect to the antenna is selected to achieve a desired operational frequency band for the RF transponder. Specifically, the spacing between the antenna and the parasitic element is selected to achieve the desired operational frequency band. For example, a first selected spacing may enable an operational frequency band suitable for a first geographic region (e.g., the United States), a second selected spacing may enable an operational frequency band suitable for a second geographic region (e.g., Europe), and a third selected spacing may enable an operational frequency band suitable for a third geographic region (e.g., Japan).

Abstract: An antenna minimizes radiation from the outer conductor (44) of a coaxial cable (40) that is coupled to the antenna by providing a balancing tab (90) that lies near the connection (72) of the cable outer conductor (44) to the antenna. One antenna includes a Yagi structure (12) constructed of a plate of metal that forms a long boom (20) and a plurality of directors (28) extending laterally across the boom, with an electrical coupling loop mounted at a rear region of the Yagi structure. The coupling loop includes a folded dipole in the form of a metal coupling plate that forms a loop (54) with a gap (70), the loop having a laterally elongated front loop end (60). The Yagi structure is formed with a balancing tab (90) that lies forward of the loop, that has a lateral length (D) less than half that of one of the directors, and that extends from only one side (22) of the boom which is the side to which the outer coax conductor (44) is connected to the loop.

Abstract: A wireless communication device includes a mobile wireless communication signal creation and reception circuit (310) coupled to a resonator (320) capable of sending and/or receiving wireless communication signals. A parasitic element (340) is coupled to the resonator (320) in an approximately orthogonal arrangement such that the parasitic element (340) and the resonator (320) resonate together to send and/or receive a wireless communication signal. Preferably, the parasitic element (340) and resonator (320) are contained within a housing (520) of a wireless communication device handset (500) to provide improved communications with a satellite (700).

Abstract: An antenna array, especially for spacing ascertainment or speed ascertainment in the surroundings of motor vehicles, includes devices for transmitting and/or receiving signal waves, which includes a shielding layer construction, made up of at least two layers, which includes the transmitting or receiving devices at least in part. To achieve above all a good immunity to interference, the antenna array includes a differential input buried in a dielectric layer and it includes a transmitting and/or receiving dipole, which is composed of two separate dipole halves.

Abstract: A multiband antenna includes at least two resonators that are driven directly and resonate in different frequency bands and a parasitically coupled resonator that resonates in one of the frequency bands. The coupled resonator is grounded with a conductive trace at one end and is thus not directly fed by the RF feed of the antenna. The coupled resonator increases the efficiency bandwidth near the frequency of operation for the coupled resonator. The antenna is fabricated from a stamped metal that is bent around or overmolded by a spacer layer. A clip formed integrally with the antenna by bending a portion of the ground plane permits attachment to the metal shield of the display of a laptop computer and is thus grounded along its length.

Abstract: An antenna comprising a rectangular reflector; first and second dipole antennae disposed in front of the reflector and aligned parallel to the long edge of the reflector; rod-shaped first metal conductors arranged parallel to the first and second dipole antennae and separated from the dipole antennae by a distance X1 to the outside in the direction parallel to the short edge of the reflector, and separated by a distance Y1 in the direction perpendicular to the reflector; and rod-shaped second metal conductors disposed at a position separated from the dipole antennae by a distance X2 greater than distance X1 to the outside with respect to each other, and separated by a distance Y2 greater than distance Y1 forward in the direction perpendicular to the reflector.

Abstract: A directional antenna array is provided that includes a driven element and a first parasitic element separated from the driven element with the first parasitic element and/or the driven element having a width that is greater than about one-half a percent (0.5%) of an free-space wavelength of the directional antenna array. Alternatively or in conjunction, the directional antenna array includes a balun structure that is configured to couple the driven element to at least one of an electromagnetic energy source and an electromagnetic sink, and the balun structure includes a dipole structure, a first feed point extending from the dipole structure and a second feed point extending from the first parasitic element.

Abstract: An antenna array that uses at least two passive antennas and one active antenna disposed above a ground plane, but electrically isolated from the ground plane, and a respective resonant strip positioned beneath each passive antenna. The passive antenna elements are positioned about the active element, and each of the at least two passive antenna elements is individually set to a reflective or a transmissive mode to change the characteristics of an input/output beam pattern of the antenna apparatus.

Abstract: An antenna device is provided which is capable of dealing with two or more frequencies or of carrying out communications using two or more communication methods by a single antenna and of controlling its directivity and, therefore, of achieving improvements in communication performance of the antenna device. The antenna device is so constructed that its shape is freely changed and its directivity can be changed to deal with a signal in any frequency band. The antenna device is made up of two or more antenna elements and switches which put each of the antenna elements into a connected or disconnected state. By controlling the switches, a shape of the antenna is changed so as to have a 90-degree bent dipole configuration to provide directivity, and a length of the antenna is changed so as to allow a changeover of a frequency band. The antenna device has a reflector being similar to the dipole-type antenna, which enables improvements in its directivity.

Abstract: Navigation apparatus that may include a radio receiver, at least one directional antenna communicatively coupled to the radio receiver, and a navigation computer including a memory and a processor. The navigation computer may be communicatively coupled to the radio receiver to receive relative bearing information from the directional antenna to a set of known radio transmitters, such as (but not limited to) commercial broadcast radio or television stations. Using a database stored in the memory that includes a record of position information and a record of radio frequency information for the set of known radio transmitters, the apparatus allows for the calculation of one or more reference positions using relative bearing information to the set of known radio transmitters and the stored, known positions of the set of known radio transmitters.

Abstract: The invention provides a dual-access antenna fabricated on a substrate. In one embodiment, the antenna includes a first monopole element, at least one grounded parasitic element located proximate the first monopole element, wherein the separation between the monopole and the grounded parasitic element exhibits a conductive profile which varies the waveguide characteristics of the antenna assembly. The conductive profile is provided by a stepped or angled profile on the or each grounded parasitic element which faces and extends away from first monopole element. This antenna covers the frequency range 900 to 2300 MHz. The antenna includes a secondary grounded element located at an outer position relative to the or an associated grounded parasitic element. In a preferred embodiment, the antenna includes two grounded parasitic elements located on opposite sides of the first monopole element.

Abstract: A printed circuit board has an inverted-L-shaped antenna pattern, which is provided with a conductor pattern connected to a ground pattern, so formed thereon as to be in close proximity to the outside of an inverted-F-shaped antenna pattern which is provided with a conductor pattern connected to a feeding point and with a conductor pattern connected to a ground pattern. By making resonance frequency of each of the inverted-F-shaped antenna pattern and the inverted-L-shaped antenna pattern different, it is possible to compose a frequency antenna using different frequency bands.

Abstract: A compact microstrip antenna having elements comprising a Yagi-Uda array is provided for use in an apparatus communicating through the antenna. The microstrip Yagi-Uda antenna is adapted for use in an apparatus such as a cellular phone, PDA, laptop computer, or a vehicle having a telematices device.

Abstract: An antenna on a printed circuit board (PCB) with a compensating capacitor. The antenna has a radiator disposed over a first surface of the PCB. Wherein the radiator includes a signal feeding section and a tuning section coupled together at a joint. The tuning section includes a bending portion. Also and, a ground layer with or without a protuding portion is disposed on a second surface of the PCB, wherein the bending portion of the tuning section is overlapping with the ground layer to form the compensating capacitor. In addition, the radiator can also have a short circuit stub section, electrically coupled to the ground layer.

Abstract: An improved dual-polarized antenna element arrangement has half-dipole components which interact with each other and, from the electrical point of view, each form of dipole half connected via an electrical connector or a transverse strut, to be precise offset with respect to the outer corner region in the direction of the center of the antenna element arrangement.

Abstract: An adaptive antenna unit is adapted to a mobile terminal for making mobile communication and adaptively forms an antenna directivity in a direction of a base station which exchanges signals with the mobile terminal. The adaptive antenna unit is provided with an azimuth sensor to detect at least one of rotation, inclination and present position of the mobile terminal, a transmitter-receiver section to control the antenna directivity in a direction in which a reception characteristic improves based on reception signals received from a plurality of antenna elements forming the antenna directivity, and a mechanism for correcting the antenna directivity in the direction of the base station, based on the at least one of rotation, inclination and present position of the mobile terminal detected by the azimuth sensor.

Abstract: A radio frequency antenna structure includes a base station antenna and an auxiliary antenna mounted within a common antenna assembly. The base station antenna is configured to transmit or receive signals in a first frequency range and to develop a main beam that is substantially wider in azimuth than in elevation, and the auxiliary antenna is configured to transmit or receive signals in a second frequency range at least partially overlapping the first frequency range and to develop an auxiliary beam at least partially overlapping the main beam. Means are included for decoupling the base station and auxiliary antennas to thereby suppress interference between the main and auxiliary beams, and for suppressing interference between the auxiliary antenna and any co-located antennas.

Abstract: An antenna array that uses at least two passive antennas and one active antenna disposed above a ground plane, but electrically isolated from the ground plane, and a respective resonant strip positioned beneath each passive antenna. The passive antenna elements are positioned about the active element, and each of the at least two passive antenna elements is individually set to a reflective or a transmissive mode to change the characteristics of an input/output beam pattern of the antenna apparatus.

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.