Abstract: An electronic device comprising a first conductive unit and a second conductive unit disposed such that a gap exists between the first component and the second component. The electronic device further includes one or more components disposed along the gap and configured to counteract one or more capacitance effects in the gap, wherein at least one of the first conductive unit and the second conductive unit represents a part of an antenna. By counteracting the capacitance effects in the gap, certain radiation attributes of the antenna, such as radiation efficiency, can be improved. The one or more components are also employed to counteract one or more capacitance effects in a slot of a conductive unit in an electronic device.

Abstract: A ground radiation antenna is disclosed. Herein, the ground radiation antenna provides a radiator-forming circuit, which is formed to have a simple structure using a capacitive element, as well as a feeding circuit suitable for the provided radiator-forming circuit. Thus, the structure of the antenna becomes simpler and the size of the antenna becomes smaller. Accordingly, the fabrication process of the antenna is simplified, thereby largely reducing the fabrication cost.

Abstract: An antenna device for a portable terminal includes: a ground pattern provided on one surface of a circuit board; a first antenna pattern configured to resonate at a first frequency band and provided on an opposite surface of the circuit board; and a second antenna pattern configured to resonate at a second frequency band different from the first frequency band and arranged along a periphery of the ground pattern. The second antenna pattern is a zeroth order mode resonator including a plurality of capacitors and a plurality of inductors. The antenna device easily secures the operation characteristics of different operation frequency bands and contributes to miniaturization of the portable terminal. Thus, a user can conveniently carry and use the portable terminal.

Abstract: A multi-frequency antenna (1) comprises a dielectric substrate (100), an antenna element (110), a shunt inductor (120), a capacitor conductor (130), a series inductor (140), a grounded part (150) and a feeding point (160). The antenna element (110) is arranged on the substrate (100), and is electrically connected to the grounded part (150) through the shunt inductor (120). Moreover, the antenna element (110) is electrically connected to the feeding point (160) through a series capacitor formed by a part where the antenna element (110) faces the capacitor conductor (130) and the substrate (100) therebetween, and through the series inductor (140).

Abstract: A ground radiation antenna is disclosed. Herein, the ground radiation antenna provides a ground radiator inducing resonance by using the inductance of a ground. Since the ground radiator efficiently uses the inductance of the ground, the ground radiator may operate as a radiator of the ground radiation antenna by using a simple structure of combining a capacitive element with the ground. As described above, by providing an antenna radiator having a remarkably simple structure, the fabrication cost for the antenna may be decreased, and the size of the antenna may also be largely reduced.

Abstract: A transmission/reception element includes: a plurality of metal layers each disposed with space from another; and a switch for controlling electrical coupling between the metal layers. The switch includes a contact-point group including a plurality of contact-point pairs each disposed in parallel between each two of the metal layers, and a drive section mechanically driving the contact-point group for state change of each of the contact-point pairs between in-contact and no-contact.

Abstract: The present invention is a Radio Frequency (RF) apparatus. The RF apparatus may include a layer of photoconductive material. The RF apparatus may further include a plurality of conductive patches which are disposed within the layer of photoconductive material. The RF apparatus may further include a generating layer. The generating layer may be operatively coupled to the layer of photoconductive material and may be configured for generating light. The generating layer may further be configured for providing the generated light to the layer of photoconductive material. The generated light may be configurable for being provided at a selectable intensity and in a selectable pattern for causing the layer of photoconductive material to be a dynamically controllable optical switch. The dynamically controllable optical switch may be configured for providing a connection between conductive patches included in the plurality of conductive patches.

Abstract: An electronic device includes a helical resilient member serving as an electrical inductance element. The electronic device also includes an antenna, a signal feeding line, and a transmitting/receiving module. The helical resilient member has first and second ends with a predetermined number of turns of coil arranged therebetween the first and second ends, and is made of electrically conductive materials so that the turns of coil defines an electrical inductance. The signal feeding line is connected between the helical resilient member and a signal feed point of the antenna. The transmitting/receiving module is connected to the helical resilient member so as to couple the inductance of the helical resilient member to the transmitting/receiving module.

Abstract: An antenna device for a portable electronic device, preferably for the FM frequency range, generally includes a monopole radiating and/or radiation receiving element including a feeding portion adapted to be connected to an antenna connection point. An inductor is connectable between the antenna connection point and ground. The input of an amplifier stage is also connectable to the antenna connection point. An output of the amplifier stage is connectable to a radio circuit, all provided in the interior of the portable electronic device.

Abstract: An integrated multi-band antenna comprises a first conductor, a second conductor, at least one inductor member, an extension conductor, and a grounding plane. The first conductor and a first branch of the second conductor form a first coupling region. The inductor member is arranged near the first branch. The extension conductor is arranged near a second branch of the second conductor and extends therefrom to form a terminal. The terminal and first conductor form a second coupling region. The first and second coupling regions are arranged on opposite sides of the first conductor. The second branch connects to the grounding plane. The present invention adopts a design incorporating the capacitive coupling of the conductors and the choke of the inductor member, integrates the standard frequency bands of the low-frequency and high-frequency systems of the digital TV to achieve a miniaturized digital TV antenna spanning a wide range of frequency bands.

Abstract: A planar multi-band antenna includes a substrate and a metal pattern. The metal pattern includes a first metal wire, a second metal wire, a third metal wire and a fourth metal wire. The second metal wire is disposed opposite to the first metal wire and has a grounding point. Two ends of the third metal wire are connected to the first metal wire and second metal wire, respectively, and the first metal wire is divided into a first radiation portion and a second radiation portion. The fourth metal wire is partially located between the second radiation portion and the second metal wire and forms multiple bends, and has a first impedance matching portion and a feed point, and part of the fourth metal wire coincides with the second radiation portion in a projection direction. By the activation of the feeding point and the grounding point associates with the impedance matching portion, the antenna has plural bands.

Abstract: A three-dimensional multi-frequency antenna includes a substrate; a shorting wall vertically formed on a first edge of the substrate; a radiation element including a first radiator corresponding to a first resonance frequency band, and a second radiator corresponding to a second resonance frequency band, the first radiator and the second radiator capable of generating a frequency-multiplying third resonance frequency extending toward opposite directions; and a connection element, for connecting the shorting wall and the radiation element, separated from a second edge of the substrate by a gap; wherein the width of the radiation element and the gap conforms to a specific ratio.

Abstract: A secondary antenna in a wireless communication terminal is provided. The secondary antenna includes an electrically conductive planar element that includes a first edge that is substantially linear and that includes a first length. The electrically conductive planar element may include a second edge that is substantially linear, that is opposite the first edge and that includes a second length that is less than the first length. At least one curved edge may be arranged between the first edge and the second edge. At least one elongated slot that is substantially perpendicular to the second edge may originates from a transition portion between the at least one curved edge and the second edge.

Abstract: Dual-band and multi-band radiating elements are described based on composite right/left-handed (CRLH) meta-material transmission line (TL). These elements can operate as resonators and/or antennas depending on feed-line configuration. The radiating elements are based on the fundamental backward wave supported by a composite right/left-handed (CRLH) meta-material transmission line (TL). Unit-cells of the transmission line comprise conductive patches coupled through vias to a ground plane. The physical size and operational frequencies of the radiating element is determined by the unit cell of the CRLH meta-material. This radiating element is configured for monopolar radiation at a first resonant frequency and patch-like radiation at a second resonant frequency. The first and second resonant frequencies are not constrained to a harmonic relationship.

Abstract: An antenna system internal to a radio device, the system comprising separate antennas and having separate operating bands. The system is implemented as decentralized in a way that each antenna is typically based on a small-sized chip component, which are located at suitable places on the circuit board and possibly on also another internal surface in the device. The chip component comprises a ceramic substrate and at least one radiating element. The operating band of an individual antenna covers, for example, the frequency range used by a radio system or only the transmitting or receiving band in that range. At least one antenna is connected to an adjusting circuit with a switch, by which the antenna's operating band can be displaced in a desired way. In this case the operating band covers at a time a part of the frequency range used by one or two radio systems.

Abstract: An antenna includes a dielectric substrate and an antenna element. The antenna element includes a power feeding element and a reference potential element. The power feeding element includes a first conductive layer formed over the dielectric substrate, the first conductive layer extending in a first direction and having a first length along the first direction. The reference potential element includes a second conductive layer formed over the dielectric substrate, the second conductive layer extending in a second direction opposed to the first direction from a second position, the second point being apart by a first distance from a first position on an end of the first conductive layer, and a third conductive layer formed over the dielectric substrate, the third conductive element extending from the second point in the first direction apart by a second distance from the first conductive layer and having a third length along the first direction.

Abstract: An antenna is provided, in combination with an associated switch array, the antenna comprising a number of antenna elements mounted above a ground plane for providing coverage over a predetermined range of angles in azimuth using a number of beams. Each of the antenna elements is connected to a switch in the switch array and the switch array is operable to connect selected pairs of the antenna elements to a signal path to thereby generate each of the different beams, at the same time connecting unselected antenna elements to ground.

Abstract: The invention as disclosed is of a buoyant cable antenna for use with underwater vehicles having improved bandwidth through the use of discrete distributed loading along the antenna. The buoyant cable antenna is designed with an antenna wire that is divided into N equal length segments of length d/2. A capacitor is coupled between every other segment such that capacitors are separated by a distance d. A shunt inductor is coupled to the antenna wire between the adjoining segments not separated by a capacitor such that the shunt inductors are separated by a distance d. This antenna design provides a substantially improved impedance bandwidth over existing prior art antennas at high frequency without increasing the physical profile of the antenna and without the use of active circuit elements.

Abstract: A multiband single-strip monopole antenna includes a dielectric substrate, a ground plane, and a radiating portion. The ground plane is disposed on one surface of the dielectric substrate without completely covering the surface of the dielectric substrate. The radiating portion is disposed on the surface of the dielectric substrate without overlapping the ground plane, and is internally embedded with an inductive element, via which a continuous path through the inductive element is formed between a start point and an open end of the radiating portion. Since the inductive element can compensate for an increased capacitive reactance caused by a reduced antenna length, good antenna matching can still be achieved even when the size of the antenna is reduced.

Abstract: A vertical dipole-style antenna operable over a wide range of predetermined frequencies that is made up of two collinear dipole antennas fed either in parallel through a single input connector or individually through two input connectors, contained within the same enclosure, where one dipole covers the VHF portion of the band from 30 MHz to 115 MHz and the other dipole covers the remainder of the band from 115 MHz to 512 MHz and together the two dipoles cover the very wide frequency band of 30 to 512 MHz through a single input connector. The VHF dipole is comprised of an existing vehicular dipole antenna design, while the UHF dipole antenna is comprised of radiating elements fed with a specially design coaxial transformer feedline with wide-band capacitive elements coupling the radiating elements to ground, providing variable loading to control the electrical length of the antenna.

Abstract: The invention provides an antenna structure with reconfigurable pattern, which comprises a grounded plane, at least an active antenna electrically connected to an RF signal source, at least a current dragger electrically connected to the grounded plane, and a controller. The at least an active antenna and the at least a current dragger are distributed on or near the grounded plane. The controller disables or enables the at least a current dragger at an operating frequency band to switch the RF current applied to the grounded plane to flow into or against the at least a current dragger, thereby a plurality of radiation patterns may be configured.

Abstract: A linear antenna for operation in the HF frequency range, particularly for naval communications is disclosed, comprising a radiating arrangement (H1, H2, H3, W1, W2), adapted to be operatively associated with a ground conductor (20) and at least one electrical impedance device (Z1-Z4), characterized in that it includes: a plurality of wire radiating elements with a predominantly vertical extension, forming a first and a second conducting branch (H1, H2) adapted to be operatively coupled to a feed circuit, and a return conducting branch (H3) adapted to be operatively coupled to a ground conductor (20); and a plurality of wire radiating elements with a predominantly transverse extension, forming connecting conducting branches (W1, W2) for connecting the conducting branches (H1, H2) adapted to be coupled to the feed circuit (12), to the conducting branch (H3) adapted to be coupled to the ground conductor (20), the radiating elements being positioned in such a way as to form, in a plane in which the antenna lies,

Abstract: An antenna arrangement for radio communication in a first radio communication band and for communication in a second radio communication band including a multiple-resonance antenna element having a feed for connection to radio frequency circuitry; and a load connected to the feed and comprising a plurality of reactive components including a first reactive component that controls the impedance of the load for the first radio communication band and a second reactive component, separate from the first reactive component, that controls the impedance of the load for the second radio communication band wherein the plurality of reactive components of the load are configured to provide an impedance that changes between being inductive at a first frequency in the first radio communication band to being capacitive at a second frequency in the first radio communication band and that changes between being inductive at a third frequency in the second radio communication band to being capacitive at a fourth frequency in th

Abstract: First, second and third feed ports interface to an antenna that has an impedance disposed between its ends which are defined by the first and second feed ports. The third feed port interfaces to the antenna at an intermediate point between the ends. In a first mode (balanced mode) the impedance enables signals to/from the first and second feed ports to resonate along the whole of the antenna, and in a second mode the impedance enables signals to/from the third feed port to resonate along a portion of the antenna, the portion terminating at the impedance. In embodiments, the first mode is for RFID signals and the second mode is for any one or more of Bluetooth/WLAN/GPS/FM signals. The first and second mode may operate simultaneously. Also detailed is a method for making an electronic device having such an antenna.

Abstract: There is an antenna, three feed ports, two switches, and two impedances. In an embodiment, the first and second feed ports interface respective FM transmitter and FM receiver, and the third feed port interfaces Bluetooth, WLAN and/or GPS radios. The two switches are disposed along the antenna. A first throw of them renders a balanced mode for the antenna seen by the first feed port and a second throw renders an unbalanced mode for the antenna seen by the second feed port. The two impedances are disposed and configured such that the antenna, for signals in a second frequency band at the third feed port and which are impeded by the two impedances, is an unbalanced mode for the first throw of the switches and is an unbalanced mode for the second throw of the switches. Also detailed is a method for making an electronic device having such an antenna.

Abstract: An apparatus including a radiator having an electrical length; a first conductive element; an interconnector, connected to the radiator and to the first conductive element, having a first configuration and a second configuration, wherein the radiator has a first electrical length when the interconnector is in the first configuration and a second electrical length, different to the first electrical length, when the interconnector is in the second configuration.

Abstract: An antenna device for a portable radio communication device operable in at least a first and a second frequency band, includes first and second electrically conductive planar radiating elements. The first radiating element has a feeding portion connectable to a feed device of the portable radio communication device. The second radiating element includes a grounding portion connectable to ground. A controllable switch is arranged between the first and second radiating elements for selectively interconnecting and disconnecting the radiating elements. The state of the switch is controlled by means of a control voltage input. A first filter is arranged between the feeding portion and the control voltage input, to block radio frequency signals. By providing a high pass filter between the first and second radiating elements above a ground plane, quad-band operation is provided with high efficiency in a physically small antenna device.

Abstract: A radio antenna assembly for use in a communication device has an antenna element disposed adjacent to a ground plane to form a physical relationship with the ground plane. A mechanical device is used to change the physical relationship for changing the operating impedance of the antenna element or shifting the frequency band of the antenna assembly. The physical relationship can be changed by mechanically changing the shape of the antenna element. When the antenna element comprises a first radiating element and a second radiating element disposed at a lateral distance from the first radiating element, the physical relationship can be changed by changing the distance. When a physical object is disposed between the antenna element and the ground plane, the physical relationship can be changed by moving or twisting the physical object. The object can be electrically conducting, dielectric or magnetic.

Abstract: An antenna arrangement operable at a first resonant frequency f having a corresponding resonant wavelength ? the antenna arrangement comprising: an antenna comprising a feed; a ground plane coupled to the antenna comprising a first region and a second region; and a grounded conductive structure coupled to the first region of the ground plane, wherein the second region of the ground plane is configured such that, at the first resonant frequency f the current flows predominantly in the grounded conductive structure compared to the second region of the ground plane.

Abstract: A multi-band antenna is adapted to operate in a first frequency band and a second frequency band which is lower than the first frequency band. In the multi-band antenna, an antenna element has an electrical length of ¾ wavelength of the first frequency band. The antenna element has a first end adapted to be electrically connected to a power feeding point, and a second end. An inductor is electrically connected between the second end of the antenna element and a ground in a serial manner. The inductor has such an inductance that an electrical length of the antenna element and the inductor corresponds to ½ wavelength of the second frequency band.

Abstract: A multi-band antenna includes a ground portion, a radiating element spaced from the ground portion, a tuning conductor extending from the radiating element and parallel to the ground portion to form a gap therebetween, a short-circuit conductor interconnecting the ground portion and the radiating element, and a feed point disposed at the radiating element and adjacent to the short-circuit conductor. The radiating element, the short-circuit conductor and the feed point function as a first inverted-F antenna obtaining a first high frequency band, and a second inverted-F antenna obtaining a low frequency band and a second high frequency band higher than the first high frequency band. The ground portion and the tuning conductor cause a capacitance effect to shift the second high frequency band to be close to the first high frequency band. It can cover various wireless communication frequency bands.

Abstract: An antenna arrangement including a ground plane having an electrical length; an antenna element positioned for coupling with the ground plane; a first conductive element; an interconnecting mechanism, connected to the ground plane and to the first conductive element, having a first configuration and a second configuration, wherein the ground plane has a first electrical length when the interconnecting mechanism is in the first configuration and a second electrical length, different to the first electrical length, when the interconnecting mechanism is in the second configuration.

Abstract: An antenna device for a portable electronic device and an electronic device provided with such an antenna are disclosed. The antenna device is configured to provide in a combination a tuning element for tuning at least one electrical dimension of the portable electronic device and an antenna radiator element of the portable electronic device.

Abstract: An antenna or a printed-circuit board is formed using a plurality of unit structures which are repetitively aligned in a one-dimensional manner or in a two-dimensional manner. The unit structure includes a conductive plane and a conductive patch which are disposed in parallel with each other, a power-supply unit applying a high frequency signal between the conductive plane and the conductive patch, and at least one shunt which is aligned in the conductive patch and which is constituted of a transmission line having an open end aligned in a plane above or below the conductive patch and a conductive via electrically connecting the transmission line to the conductive plane. Alternately, the transmission line is aligned in a plane above or below the conductive plane so that the transmission line is electrically connected to the conductive patch via the conductive via.

Abstract: A distributed load monopole antenna system is disclosed that includes a monopole antenna including a radiation resistance unit, a current enhancing unit, and a conductive mid-section. The radiation resistance unit is coupled to a transmitter base and the radiation resistance unit includes a radiation resistance unit base that is coupled to ground. The radiation resistance unit also includes a plurality of windings of an electrically conductive material wherein each winding includes an elongated portion that is substantially parallel with an elongated central axis of the monopole antenna. The elongated portions are positioned at a plurality of angularly disposed locations around the elongated central axis of the monopole antenna. The current enhancing unit is for enhancing current through the radiation resistance unit, and the conductive mid-section is intermediate the radiation resistance unit and the current enhancing unit.

Abstract: An antenna arrangement including a first antenna branch and a second antenna branch having a common feed point is provided. The first antenna branch includes a first conducting portion, a second conducting portion, and a first gap between the first and second conducting portions, and a plurality of inductor elements is connected in parallel across the first gap.

Abstract: The planar or printed chip antenna is configured to enhance the gain relative to its area. The antenna includes a dielectric substrate having first and second opposing sides and a plurality of electrically conductive traces thereon configured to define a half-loop antenna element extending along an arcuate path on a first side of the dielectric substrate and having spaced apart first and second ends. First and second base strips are electrically connected together and aligned on the respective first and second opposing sides of the dielectric substrate adjacent the spaced apart first and second ends of the half-loop antenna element. A feed strip is on the second side of the dielectric substrate and aligned with the first end of the half-loop antenna element and electrically connected thereto. At least one capacitive element is associated with the half-loop antenna element.

Abstract: An antenna may be formed from conductive regions that define a gap that is bridged by shunt inductors. The inductors may have equal inductances and may be located equidistant from each other to form a scatter-type antenna structure. The inductors may also have unequal inductances and may be located along the length of the gap with unequal inductor-to-inductor spacings, thereby creating a decreasing shunt inductance at increasing distances from a feed for the antenna. This type of antenna structure functions as a horn-type antenna. One or more scatter-type antenna structures may be cascaded to form a multiband antenna. Antenna gaps may be formed in conductive device housings.

Abstract: In an antenna structure having an effect of capacitance in serial connecting, mainly a metallic planar antenna is provided thereon at least with a first metallic plane board, and a second metallic plane board being close to but not connected to the first metallic plane board to form the effect of capacitance in serial connecting. And more, the antenna structure further has an extension arm made from a microstrip extended from the antenna or the second metallic plane board, and can be optionally grounded or not grounded, for the purpose of adjusting the impedance value of the antenna structure.

Abstract: A mobile communication device (100) is operable in several physical configurations (202, 204, 302, 304) and has a main antenna (108). A non-resonant load (124) is selectively coupled to the main antenna during transmit time slots (808) to change the operating resonance of the antenna and reduce the field strength produced by the antenna at one or more select locations of the mobile communication device.

Abstract: An X, Ku, and K-band omni-directional antenna with dielectric loading is disclosed. It comprises a conductor with a loading dielectric resonator and a ground plane. Broad frequency coverage from 7.5 to 26 GHz includes uniform azimuthal coverage from +10 to +70 degrees. The antenna can be used generally in microwave communications including Digital Radio Frequency Tags (DRaFTs) communicating with airborne and satellite platforms.

Abstract: Techniques and devices based on antenna structures with a MTM loading element.

Abstract: A horizontally polarized antenna array allows for the efficient distribution of RF energy into a communications environment through selectable antenna elements and redirectors that create a particular radiation pattern such as a substantially omnidirectional radiation pattern. In conjunction with a vertically polarized array, a particular high-gain wireless environment may be created such that one environment does not interfere with other nearby wireless environments and avoids interference created by those other environments. Lower gain patterns may also be created by using particular configurations of a horizontal and/or vertical antenna array. In a preferred embodiment, the antenna systems disclosed herein are utilized in a multiple-input, multiple-output (MIMO) wireless environment.

Abstract: A heating line pattern structure is provided, in which the effect of the heating lines of a defogger on an antenna for a TV broadcast especially for a digital TV broadcast may be decreased. The defogger is structured by arranging heating lines between bus bars on both sides. The portion of an uppermost heating line in proximity to the monopole antenna are folded rectangularly at a regular interval to form a meander shape. One lateral heating line is extended under the meander-shaped heating line portion, and is connected to a vertical heating line to which four lateral heating lines are connected together.

Abstract: According to an aspect of the invention, there is provide an antenna apparatus including: a conductive element including one end connected to a ground plane via a terminating resistor and the other end to which a power is supplied; and at least one branch conductive element branching from the conductive element and having a tip end which is short-circuited to the ground plane, and an element length of the branch conductive element being approximately a quarter wavelength of an operation frequency.

Abstract: A low-profile antenna structure can control its directivity with great flexibility. Excited elements 11 and 12 are symmetrically arranged on a y-axis, whereas parasitic elements 13 and 14 are symmetrically arranged on an x-axis, with respect to an origin. The excited elements, as well as the parasitic elements, each have an inverted-F antenna structure and are a distance of ?/4 apart from each other. Feed circuits 21 and 22 are respectively connected to and feed signals to the excited elements 11 and 12, such that phases of the signals to be fed are different from each other by a desired degree. Variable reactors 23 and 24 (i) are respectively connected to the parasitic elements 13 and 14, and (ii) in accordance with reactance values thereof, can each change an electrical length of the corresponding one of the parasitic elements.

Abstract: A system having a UHF RFID transceiver is adapted to communicate exclusively with a single electro-magnetically coupled transponder located in a predetermined confined transponder operating region. The system includes a near field coupling device comprising a plurality of lines connected in parallel with an unmatched load. The near field coupling device may be formed, for example on a printed circuit board with a plurality of electrically interconnected traces and a ground plane. The system establishes, at predetermined transceiver power levels, a mutual electro-magnetic coupling which is selective exclusively for a single transponder located in a defined transponder operating region. Also included are methods for selective communication with the transponder in an apparatus such as a printer-encoder.

Abstract: An antenna arrangement for radio communication in a first radio communication band and for communication in a second radio communication band including a multiple-resonance antenna element having a feed for connection to radio frequency circuitry; and a load connected to the feed and comprising a plurality of reactive components including a first reactive component that controls the impedance of the load for the first radio communication band and a second reactive component, separate from the first reactive component, that controls the impedance of the load for the second radio communication band wherein the plurality of reactive components of the load are configured to provide an impedance that changes between being inductive at a first frequency in the first radio communication band to being capacitive at a second frequency in the first radio communication band and that changes between being inductive at a third frequency in the second radio communication band to being capacitive at a fourth frequency in th

Abstract: A magnetic field focusing assembly includes a magnetic field generating device configured to generate a magnetic field, and a split ring resonator assembly configured to be magnetically coupled to the magnetic field generating device and configured to focus the magnetic field produced by the magnetic field generating device.

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.