Abstract: The present invention discloses an RF device for a wireless communication device, including a grounding element, an antenna, including a radiating element, a feed-in element, a coupling element, a switch, coupled between the coupling element and the grounding element, for connecting or disconnecting the grounding element to the coupling element, such that the antenna respectively operates in a first frequency band and a second frequency band, and a grounding terminal, for coupling the grounding element, a capacitive sensing element, for sensing an environment capacitance within a specific range through the radiating element, at least one capacitor, for blocking a DC route from the grounding terminal to the grounding element.

Abstract: An antenna duplexer includes a transmission filter and a reception filter both coupled with an antenna terminal. A pass band of the transmission filter is lower than a pass band of the reception filter. The transmission filter includes a first series resonator coupled with a first terminal, a second series resonator connected to the first series resonator at a first node, a first parallel resonator connected to a first port of the first series resonator, a second parallel resonator connected to a first node and the first parallel resonator at a second node, a third parallel resonator connected to the first node, a fourth parallel resonator connected to the third parallel resonator at a third node, a first inductance element coupled with the second node and a ground, and a second inductance element coupled with the third node and the ground. The first and second parallel resonators and the first inductance element produce an attenuation pole at a frequency lower than a pass band of the transmission filter.

Abstract: Multiband antennas are disclosed that incorporate a high frequency antenna element connected to a low frequency antenna element by a choking circuit. The choking circuit couples the high frequency antenna element to the low frequency antenna at a low frequency band and decouples the high frequency antenna element at a high frequency band. The connection created by the choking circuit can be a direct connection or can be an indirect connection via coupling elements that are capactively coupled to the high frequency antenna element and/or the low frequency element to increase the bandwidth of the multiband antenna. One embodiment includes a high frequency antenna element including a feed, and a low frequency antenna element connected to the high frequency antenna element via a choking circuit.

Abstract: A multiband slot loop antenna apparatus, and methods of tuning and utilizing the same. In one embodiment, the antenna configuration is used within a handheld mobile device (e.g., cellular telephone or smartphone). The antenna comprises two radiating structures: a ring or loop structure substantially enveloping an outside perimeter of the device enclosure, and a tuning structure disposed inside the enclosure. The ring structure is grounded to the ground plane of the device so as to create a virtual portion and an operating portion. The tuning structure is spaced from the ground plane, and includes a plurality of radiator branches effecting antenna operation in various frequency bands; e.g., at least one lower frequency band and three upper frequency bands. On one implementation, a second lower frequency band radiator is effected using a reactive matched circuit coupled between a device feed and a radiator branch.

Abstract: Described are a notch antenna and an array antenna based on a low profile stripline feed. The notch antenna includes a planar dielectric substrate having upper and lower surfaces. Each surface has a conductive layer with an opening therein. A notch antenna element is disposed on the conductive layer of the upper surface at the opening. A stripline embedded in the planar dielectric substrate extends under the notch antenna element. The stripline is adapted to couple an RF signal between the stripline and the notch antenna element. A conductive via is electrically coupled to the stripline and extends from the stripline to the opening in the conductive layer on the lower surface so that the RF signal is accessible at the lower surface.

Abstract: A multi-band antenna including a conductive ground plane element, a conductive driven element having a feed point and a conductive coupling element located on at least one but not all sides of the conductive driven element and coupled to the conductive ground plane element and to the conductive driven element, wherein a resonant frequency associated with the conductive coupling element is independent of a size of the conductive ground plane element.

Abstract: An exemplary embodiment of an antenna device for operation in at least two operational frequency bands generally includes a loop element having a feeding end for connection to radio communication circuitry and a grounding end for connection to ground. The antenna device also includes first filtering means connecting the grounding end to ground, and switching means parallel with the first filtering means. The switching means is configured to connect the grounding end to ground parallel with the first filtering means in a first state, to match the loop element to a first operational frequency band of the at least two operational frequency bands. The switching means is configured to connect the grounding end to an open end parallel with the first filtering means in a second state, to match the loop element to a second operational frequency band of the at least two operational frequency bands.

Abstract: The present invention relates to an antenna device for a portable radio communication device adapted for receiving and/or transmitting radio signals in at least a first and a second operating frequency band, said antenna device comprising a half-loop radiating element, comprising a feeding portion and a grounding portion, and arranged to operate at FM frequencies. The antenna device comprises a capacitor at said feeding portion and an inductor at said grounding portion, and said half-loop radiating element is arranged to simultaneously with FM frequencies operate at frequencies at least ten times higher than FM frequencies, wherein said capacitor is arranged to short circuit said half-loop radiating element to ground for frequencies at least ten times higher than FM frequencies and said inductor is arranged to short circuit said half-loop radiating element to ground for FM frequencies.

Abstract: An exemplary embodiment includes an antenna arrangement for a portable radio communication device comprising an NFC (near field communication) antenna, a BT (Bluetooth) antenna and an FM (frequency modulation) antenna. The NFC antenna, BT antenna and FM antenna are positioned in close proximity to each other and are operable simultaneously. The NFC antenna is fed through a first decoupling filter and is grounded through a second decoupling filter.

Abstract: A broadband antenna for wireless signal transmission of an electronic device comprises a base board, a radiating element, a grounding element, a shorting element, and a feeding point. The radiating element, the grounding element, and the shorting element are disposed on the base board. The radiating element comprises a first slot and a second slot. The second slot is connected to the first slot substantially. The first slot and the second slot are used to adjust the operating band of the broadband antenna. The grounding element is used to ground the broadband antenna. The shorting element is used to connect the radiating element and the grounding element. The feeding point is disposed between an edge of the base board and the shorting element, and the horizontal extended range of the first slot does not exceed the position of the feeding point.

Abstract: An antenna device includes an antenna coil that receives a magnetic field transmitted from a reader/writer and a capacitor. The antenna device also includes a magnetic sheet formed at a face-to-face position with respect to the antenna coil and configured for changing the inductance of the antenna coil. The capacitor has a temperature characteristic in which the capacitance of the capacitor is changed with changes in temperature. The magnetic sheet is formed of a magnetic material having a temperature characteristic in which the inductance of the antenna coil is made to be changed with an opposite sign of change to that of the capacitance of the capacitor that is changed with changes in temperature in the working temperature range. In this manner, the resonance frequency of the antenna circuit in the working temperature range may be brought approximately into coincidence with the oscillation frequency of the reader/writer.

Abstract: According to one embodiment, an antenna device includes a first element, a stub, and an open end element. The first element has a folded monopole structure in which a conductor is folded at a folding portion to form a forward portion and a backward portion. A base end of the forward portion is connected to a feeding point, and a distal end of the backward portion is connected to a ground via a first lumped parameter. The stub is provided between the forward portion and the backward portion of the first element so as to shunt the forward portion and the backward portion. The open end element includes a conductor placed in parallel to the first lumped parameter. A base end of the conductor is connected between the stub of the backward portion of the first element and the ground, and the distal end of the conductor is open.

Abstract: The present invention is an adjustable beamwidth, loaded monopole antenna array. The array may include four monopole antennas. Each of the antennas may include a generally symmetric, tapered radiating element and an inductive shorting wall element. The array may further include a capacitive top hat element which may be connected to each of the antennas. The array may further include a ground plane element which may be connected to each of the antennas. The array may further include a plurality of feed posts which may be connected to the antennas. Further, each feed post may be connected to a power feed line. Each radiating element may be variably phase-fed and/or uniformly phase-fed for allowing the antenna array to effect a directional beam and/or an omni-directional beam.

Abstract: A portable wireless device includes a first communication unit having a loop antenna that communicates with external devices using a first usable frequency band, and an RFID chip that performs predetermined processing with respect to information communicated by the loop antenna. A second communication unit includes a main antenna that communicates by a second usable frequency band that is higher than the first usable frequency band, and a communication processing unit that performs predetermined processing with respect to information communicated by the main antenna. A reactance component of the loop antenna is adjusted such that a high-order secondary resonance point of the first usable frequency band does not overlap the second usable frequency band.

Abstract: An antenna arrangement including a first antenna element having one or more surfaces; and a laminate attenuator, positioned adjacent a portion of at least one surface of the first antenna element, wherein the laminate attenuator is arranged or attenuating predetermined radio frequency electromagnetic waves.

Abstract: The present invention is related to a folder-type mobile communication device. The device comprises a first dielectric substrate, a first ground plane disposed on the first dielectric substrate, a second dielectric substrate, a second ground plane disposed on the second dielectric substrate, an antenna element, a metal line, and a band-stop circuit. The antenna element is located near the first ground plane and is electrically connected to a source on the first dielectric substrate. The second ground plane is electrically connected to the first ground plane through the metal line. The band-stop circuit is located either on the first ground plane or on the second ground plane. The band-stop circuit includes a slit, a capacitive element, and an inductive element. The slit is near the metal line.

Abstract: The present invention provides a multiple band antenna, including a first radiation element adapted to resonate at a first resonant frequency band by employing a resonant length, which is reduced by a coupling effect with a neighboring radiation element, a power feed unit coupled to one lower side of the first radiation element, a first inductor coupled in series to the other lower side of the first radiation element, a second radiation element adapted to face the first radiator to thereby obtain the coupling effect, wherein the second radiation element has a predetermined lower portion coupled to the first inductor, a second inductor having one end coupled in series to a predetermined upper portion of the second radiation element, and a third radiation element coupled to the other end of the second inductor, wherein the third radiation element operates as one radiation element together with the second radiation element and resonates at a second frequency band.

Abstract: Antenna systems and antenna filters are provided, for example for use in a windshield or on a roof of a vehicle. An antenna system comprises a first antenna, a second antenna, and a filter. The first antenna is configured to operate at a first frequency. The second antenna is configured to operate at a second frequency. The filter is coupled to the first antenna. The filter is configured to create an open circuit condition at the second frequency and reduce secondary radiation between the first and second antennas.

Abstract: An antenna element has a slit including a first portion and a second portion, the first portion extending in a first direction so as to separate first and second feed points from each other, and the second portion extending in a second direction different from the first direction. The slit is configured to resonate at an isolation frequency to produce isolation between the first and second feed points, and configured to form a current path around the slit. A current distribution along the current path generated by exciting through the first feed point is different from a current distribution along the current path generated by exciting through the second feed point, thus providing different radiation characteristics by the different current distributions.

Abstract: The present invention relates to an infinite wavelength antenna device, which includes: a board body made of a dielectric and having a slab structure; a feed part arranged on one surface of the board body, and generating a magnetic field when power is applied; and an MNG resonance part arranged on the board body so that a preset distance is maintained from the feed part and at least a portion thereof is placed within the magnetic field, grounded through both ends thereof, resonating at a specific frequency band when the magnetic field is generated, and having a negative permeability. In the present invention, as the infinite wavelength antenna device operates according to the infinite wavelength property, the resonant frequency band may be determined independently of the size of the antenna device. Hence, miniaturization of the infinite wavelength antenna device can be realized.

Abstract: An antenna assembly is provided suitable for use with a remote communications module such as, for example, a keyless entry module, a tire pressure monitoring module, etc. The antenna assembly generally includes a support, a folded metallic antenna element mounted on the support, an amplifier coupled to the folded antenna element, and a transmission line coupled to the amplifier.

Abstract: A Multiple-Input Multiple-Output (MIMO) antenna system with multiple antennas is provided. The MIMO antenna system includes a number of conductive elements, and a number of band stop devices. The conductive elements are spaced apart from each other and operate in corresponding resonant frequency bands respectively when they receive electric power. When the conductive elements are operated, the band stop devices block interference between the conductive elements in the resonant frequency bands, and isolate the conductive elements from each other. The band stop devices are located between adjacently separate conductive elements and connect the conductive elements to each other. The MIMO antenna system can stop interference between the conductive elements via the band stop devices, thereby increasing the operational efficiency of the conductive elements.

Abstract: The present invention provides an antenna for transmitting/receiving a first frequency signal and a second frequency signal. The antenna includes a first frequency antenna branch for transmitting/receiving the first frequency signal, a second frequency antenna branch separated from the first frequency antenna branch for transmitting/receiving the second frequency signal and an inductance for connecting the first and second frequency antenna branches in series with one another. The inductance is capable of preventing the first frequency signal passing through the second frequency antenna branch.

Abstract: A system that includes a phase shifter and a radiating element of an electrical circuit; wherein the phase shifter is arranged to: (a) receive, from a first lead of a feed line, a first signal that is a radio frequency (RF) signal; (b) delay the first RF signal by about 180 degrees to provide a delayed signal; and (c) provide the delayed signal to a first feeding point of the radiating element; wherein the radiating element further comprises a second feeding point that is arranged to receive from a second lead of the lead line a second signal that is a RF signal; wherein the delayed signal and the second signal are substantially in phase. The system can include or be an improved MB antenna.

Abstract: An antenna element 1 is installed at a glass part 5 of a vehicle 4. The antennal element 1 has a ground part 3 and a radiating element 2. A metallic part side ground part 3b of the ground part 3 is overlapped with a metallic part 6 of the vehicle 4, while a glass part side ground part 3a of the ground part 3 and the radiating element 2 are not overlapped with the metallic part 6. The ground part 3 is installed such that a ratio of the area of the glass part side ground part 3a to be overlapped with the glass part 5 to the area of the metallic part side ground part 3b to be overlapped with the metallic part 6 is from 1:5 to 1:10.

Abstract: An antenna apparatus includes a slit provided on an antenna element between first and second feed ports; and a series resonant circuit provided at a location along the slit, with a distance from an opening of the slit. When the antenna apparatus operates at a first isolation frequency identical to a resonance frequency of the series resonant circuit, the series resonant circuit is short-circuited, and only a section of the slit from its opening to the series resonant circuit resonates, thus providing isolation between the feed ports at the first isolation frequency. When the antenna apparatus operates at a second isolation frequency lower than the first isolation frequency, the series resonant circuit is open, and the entire slit resonates, thus providing isolation between the feed ports at the second isolation frequency.

Abstract: A method for processing signals includes generating a frequency response adjusted signal of an antenna, and adjusting a gain of the antenna by varying a gain of a programmable amplifier that amplifies the frequency response adjusted signal. The generating of the frequency response adjusted signal may take place prior to the gain adjusting. A frequency response of the antenna may be dynamically adjusted during the generating. A programmable filter used for the generating may be autonomously adjusted. The gain of the antenna may be dynamically adjusted. The gain of the programmable amplifier may be autonomously varied. The programmable filter and the programmable amplifier may be adjusted sequentially.

Abstract: According to one embodiment, an antenna apparatus comprises a first antenna element, a first lumped constant element, a first lumped constant element, a switch and at least one second lumped constant element. The first antenna element comprises a forward part, a folded part and a backward part, the forward part includes a start point connected to a feeding point, and the backward part includes an end point connected to ground. The first lumped constant element is inserted in the backward part. The switch is configured to select a current path in accordance with a control signal. The at least one second lumped constant element is to be selectively connected in parallel to the first lumped constant element through the switch.

Abstract: The present invention is related to a folder-type mobile communication device. The device comprises a first dielectric substrate, a first ground plane disposed on the first dielectric substrate, a second dielectric substrate, a second ground plane disposed on the second dielectric substrate, an antenna element, a metal line, and a band-stop circuit. The antenna element is located near the first ground plane and is electrically connected to a source on the first dielectric substrate. The second ground plane is electrically connected to the first ground plane through the metal line. The band-stop circuit is located either on the first ground plane or on the second ground plane. The band-stop circuit includes a slit, a capacitive element, and an inductive element. The slit is near the metal line.

Abstract: Provided is a capacity loaded planar antenna with short stubs that can be brought to a small size and a low profile, achieves wider bandwidth, and can be tuned to multiple frequencies. A capacity loaded planar antenna with short stubs that has a simple structure and can be easily manufactured includes a base plate, an antenna element disposed so as to be parallel to the base plate, a plurality of short stubs that connect the antenna element to the base plate, and a side wall formed on the end of the base plate. The capacity loaded planar antenna achieves wider bandwidth with the small size and low profiled, can be tuned to multiple frequencies by adjusting the length of the short stubs, and uses plate-shaped foldable short stubs that are integrated with the antenna element.

Abstract: A compact multiple-band antenna for wireless devices having a plurality of operating frequency bands is provided.

Abstract: It is an object of the present invention to provide a semiconductor device which can be surely supplied electric power by electromagnetic waves in different frequency bands without preventing reduction in size and weight of a semiconductor device. A semiconductor device capable of wireless communication is provided with a frequency determining circuit which detects the frequency of the electromagnetic waves received by the antenna and a circuit which automatically adjusts impedance in accordance with information from the frequency determining circuit, and the semiconductor device communicates and obtains electric power by one antenna. For adjustment of impedance, a circuit which can change the inductance or the capacitance, or an antenna which can change the length is used.

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 first antenna element and a second antenna element. The first antenna element and the second antenna element are both configured to receive signals in a first band of frequencies and in a second band of frequencies. Frequencies in the second band of frequencies are greater than frequencies in the first band of frequencies. A first impedance matching circuit, coupled to the first antenna element, includes a first plurality of filters having a first shared component. A second impedance matching circuit, coupled to the second antenna element, includes a second plurality of filters having a second shared component. A feed network circuit is coupled to the first impedance matching circuit and to the second impedance matching circuit and has a combined output corresponding to the signals received by the first antenna element and a second antenna element.

Abstract: An antenna (2-20) for use in a mobile device (1-1) includes elements for receiving (2-5, 3-1, 4-1, 5-1, 6-5) a signal from a satellite positioning system; a first layer of dielectric material (2-4a, 2-4b, 3-2, 3-3, 5-2, 4-3, 5-2, 5-3, 6-4, 6-15) and a second layer of dielectric material (2-4a, 2-4b, 3-2, 3-3, 5-2, 4-3, 5-2, 5-3, 6-4, 6-15), wherein the elements for receiving (2-5, 3-1, 4-1, 5-1, 6-5, 7-6) the signal is at least partly between the first dielectric layer (2-4a, 2-4b, 3-2, 3-3, 5-2, 4-3, 5-2, 5-3, 6-4, 6-15) and the second dielectric layer (2-4a, 2-4b, 3-2, 3-3, 5-2, 4-3, 5-2, 5-3, 6-4, 6-15).

Abstract: The present invention relates to a broadband antenna for at least six frequency bands provided on an isolating antenna support structure comprising. The antenna comprises a low band branch and a high band branch coupled to a substantially rectangular ground plane provided on a PCB. The coupling between the ground plane and the low band branch is a capacitive coupling and has a vertical distance of 3-7 mm there in between.

Abstract: The present invention relates to an antenna device for a portable radio communication device adapted for receiving and/or transmitting radio signals in at least a first and a second operating frequency band, said antenna device comprising a half-loop radiating element, comprising a feeding portion and a grounding portion, and arranged to operate at FM frequencies. The antenna device comprises a capacitor at said feeding portion and an inductor at said grounding portion, and said half-loop radiating element is arranged to simultaneously with FM frequencies operate at frequencies at least ten times higher than FM frequencies, wherein said capacitor is arranged to short circuit said half-loop radiating element to ground for frequencies at least ten times higher than FM frequencies and said inductor is arranged to short circuit said half-loop radiating element to ground for FM frequencies.

Abstract: An array antenna apparatus includes a first antenna element resonating at a first frequency and a second antenna element resonating at the first frequency, and includes a first connecting line that connects the first connection point located in the first antenna element with a third connection point located in the second antenna element, and a second connecting line that connects the second connection point located in the first antenna element with a fourth connection point located in the second antenna element. Electrical lengths of the first and second antenna elements and those of the first and second connecting lines are set so that a phase difference, between first and second high-frequency signals respectively propagating through first and second signal paths, becomes substantially 180 degrees at the first feeding point, and then, the array antenna apparatus resonances at the first frequency and the second frequency.

Abstract: Aspects of a method and system for equalizing antenna circuit matching variations may include adjusting a frequency response of an antenna via a programmable filter and a gain of the antenna by varying a programmable amplifier. The antenna frequency response and the antenna gain may be adjusted dynamically and/or autonomously. The programmable amplifier and the programmable filter may be adjusted sequentially or simultaneously. The programmable filter may be an LC-type circuit and the programmable amplifier may be a low-noise amplifier. In an exemplary embodiment of the invention, the programmable filter may comprise a programmable capacitance in a matrix arrangement and/or a programmable inductance in a matrix arrangement.

Abstract: A multimode antenna structure is provided for transmitting and receiving electromagnetic signals in a communications device. The communications device includes circuitry for processing signals communicated to and from the antenna structure. The antenna structure includes a plurality of antenna ports for coupling to the circuitry; a plurality of antenna elements, each operatively coupled to a different one of the antenna ports; and a plurality of connecting elements. The connecting elements each electrically connect neighboring antenna elements such that the antenna elements and the connecting elements are arranged about the periphery of the antenna structure and form a single radiating structure.

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: Provided is a parabolic antenna that suppresses leakage of radio waves with a simpler configuration. The parabolic antenna includes a horn that transmits and receives signals; a feed that supports the horn and relays the signals the horn transmits and receives; a reflector that reflects the received signals to focus the received signals on the horn and reflects the signals from the horn to transmit the signals; a reflecting mirror supporting member that supports the reflector; and a feed fitting adapter that enables the feed to be fitted into the reflecting mirror supporting member. A choke groove is formed in at least one of a joint area between the reflecting mirror supporting member and the reflector and a joint area between the reflecting mirror supporting member and the feed fitting adapter, which suppresses propagation of radio waves traveling through the gap of the joint area.

Abstract: A combined antenna transmitter joined for transmitting a message signal includes a switching signal source modulated by the message signal. The switching signal is provided to a transistor at an operating frequency. The transistor switches a high voltage input through the transistor, a choke inductor and a boost inductor. A bypass capacitor is provided between the inductors for shielding the high voltage input. An antenna is connected between the boost inductor and the transistor for transmitting a radio frequency signal at the operating frequency. There is thus provided a compact, efficient transmitter and antenna assembly for transmitting modulated message signals.

Abstract: This application relates to slot antenna devices based on Composite Right and Left Handed (CRLH) metamaterial (MTM) structures.

Abstract: An inverted-F antenna is provided that has a resonating element arm and a ground element. A shorting branch of the resonating element arm shorts the resonating element arm to the ground element. An antenna feed that receives a transmission line is coupled to the resonating element arm and the ground element. One or more impedance discontinuity structures are formed along the resonating element arm at locations that are between the shorting branch and the antenna feed. The impedance discontinuity structures may include shorting structures and capacitance discontinuity structures. The impedance discontinuity structures may be formed by off-axis vertical conductors such as vias that pass through a dielectric layer separating the antenna resonating element arm from the ground element. Capacitance discontinuity structures may be formed from hollowed portions of the dielectric or other dielectric portions with a dielectric constant that differs from that of the dielectric layer.

Abstract: An apparatus includes an antenna (e.g., a monopole), a first load, and a second load. The antenna, which extends substantially along an axis, has a first end and a second end. The first load is coupled to the antenna at the first end, while the second load is coupled to the antenna between the first end and the second end. Both the first and second loads are symmetrical with reference to the axis. The apparatus is arranged to operate in at least two frequency bands, such as the AMPS band from about 824 MHz to 894 MHz and the PCS band from about 1850 MHz to 1990 MHz.

Abstract: The tulip antenna has two orthogonally intersecting conductive plates. Each intersecting plate has two ends, and one of these ends is smoothly tapered. The intersecting plates intersect such that the tapered end of both plates together form a tapered side when the intersecting plates intersect. An inner conductor of a coaxial cable is connected to the two intersecting plates at the tapered side of the intersecting plates. The inner conductor and the surrounding insulator pass through a tuning stub and then through a metallic ground plate. The tuning stub is connected to the ground plate. An aperture in the ground plate is sized such that the insulator can pass through it, just as the insulator can pass through the tuning stub. The tuning stub increases the upper frequency limit over which the antenna operates. The outer conductor of the coaxial cable is attached to the ground plate.

Abstract: An antenna apparatus is provided with two feed ports respectively provided at positions on an antenna element, and the antenna element is simultaneously excited through the two feed ports so as to simultaneously operate as two antenna portions respectively associated with the two feed ports. The antenna apparatus is further provided with a slit provided between the two feed ports, for changing a resonant frequency of the antenna element and producing isolation between the feed ports at a isolation frequency, and provided with matching means for shifting an operating frequency of the antenna element from the changed resonant frequency to the isolation frequency.

Abstract: The present invention provides a multiple band antenna, including a first radiation element adapted to resonate at a first resonant frequency band by employing a resonant length, which is reduced by a coupling effect with a neighboring radiation element, a power feed unit coupled to one lower side of the first radiation element, a first inductor coupled in series to the other lower side of the first radiation element, a second radiation element adapted to face the first radiator to thereby obtain the coupling effect, wherein the second radiation element has a predetermined lower portion coupled to the first inductor, a second inductor having one end coupled in series to a predetermined upper portion of the second radiation element, and a third radiation element coupled to the other end of the second inductor, wherein the third radiation element operates as one radiation element together with the second radiation element and resonates at a second frequency band.

Abstract: The present invention discloses an antenna for ultra-wideband (UWB) communication having a band-stop characteristic. According to an embodiment of the present invention, the UWB antenna is a patch antenna employing microstrip feeding. In order to expand a bandwidth at a low frequency band, a stub is formed in a radiating element. Furthermore, since steps are formed in a ground plane, an antenna characteristic at an intermediate frequency band can be improved and a UWB characteristic can be obtained. According to another embodiment of the present invention, the UWB antenna is a patch antenna employing microstrip feeding and has a recess formed in the ground plane, thereby implementing the UWB characteristic. The antenna of the present invention has an inverse U-shaped slot formed in the radiating element, thus implementing the band-stop characteristic at the UNII band.