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: The present invention provides an antenna for multiple bands employing a single antenna element 10, capable of operating in multiple frequency bands, and ideal for size reduction purposes. One end A of an antenna element 10 is electrically connected to a feeding point 12 and intermediate points B and C and the other end thereof is electrically connected via switches SWb, SWc, and SWd to a ground conductor 14. The electrical lengths of the antenna element 10 from the terminal to the intermediate points B and C plus connection lines from these points via the switches SWb and SWc to the ground conductor 14 and the electrical length from the one end A to the other end D plus a connection line from the other end via the switch SWd to the ground conductor 14 are set to be capable of resonating different desired frequency bands. By closing one of the switches SWb, SWc, and SWd, one of the desired frequencies can be selected and the antenna can resonate with that frequency.

Abstract: A multi-band antenna is adapted to operate in a first frequency band and a second frequency band which is higher than the first frequency band. A first antenna element is adapted to operate in the first frequency band, and has a first end which is electrically connected to the power feeding point and a second end which is electrically made open. A second antenna element is adapted to operate in the second frequency band, and has a third end which is electrically connected to the power feeding point and a fourth end which is electrically connected to the ground conductor. An electrical length of the first antenna element is set to ½ wavelength of the second frequency band, and an electrical length of the second antenna element is set to ¼ wavelength of the first frequency band.

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: The present invention provides an antenna for multiple bands employing a single antenna element 10, capable of operating in multiple frequency bands, and ideal for size reduction purposes. One end A of an antenna element 10 is electrically connected to a feeding point 12 and intermediate points B and C and the other end thereof is electrically connected via switches SWb, SWc, and SWd to a ground conductor 14. The electrical lengths of the antenna element 10 from the terminal to the intermediate points B and C plus connection lines from these points via the switches SWb and SWc to the ground conductor 14 and the electrical length from the one end A to the other end D plus a connection line from the other end via the switch SWd to the ground conductor 14 are set to be capable of resonating different desired frequency bands. By closing one of the switches SWb, SWc, and SWd, one of the desired frequencies can be selected and the antenna can resonate with that frequency.

Abstract: A dielectric carrier is disposed on a substrate and formed with a recess. A first antenna element is provided on at least one face of the carrier and electrically connected to the substrate. A second antenna element is provided as a ceramic antenna and disposed in the recess. A first dielectric layer is provided between the first antenna element and the second antenna element. A second dielectric layer is provided between the substrate and the second antenna element. The recess is formed at a position which is sufficiently away from a power supply point to the first antenna element and a point at which a potential of the first antenna element has a maximum value.

Abstract: The present invention provides a broad-band antenna for mobile communication in which a desired antenna characteristic is obtained in plural frequency bands of a portable phone or the like. A metal plate 16 having a suitable shape is disposed on an upper surface of a carrier 14 provided on a circuit board 10, and a first and a second antenna elements functioning as inverted-F antennas respectively resonant at a first frequency band and a second frequency band higher than the former are formed by electrically connecting the metal plate 16 to a grounding plate 12 and the circuit board 10 by an earthing terminal 18 and a feed terminal 20, respectively. A third antenna element 24 having a base end electrically connected to the feed terminal 20 and resonant at a third frequency band higher than the second frequency band is provided on a side surface of the carrier 14, ends of the second antenna element and the third antenna element 24 are disposed to be spaced from each other by a distance of 0.

Abstract: A dielectric carrier is disposed on a substrate and formed with a recess. A first antenna element is provided on at least one face of the carrier and electrically connected to the substrate. A second antenna element is provided as a ceramic antenna and disposed in the recess. A first dielectric layer is provided between the first antenna element and the second antenna element. A second dielectric layer is provided between the substrate and the second antenna element. The recess is formed at a position which is sufficiently away from a power supply point to the first antenna element and a point at which a potential of the first antenna element has a maximum value.

Abstract: The present invention provides a broad-band antenna for mobile communication in which a desired antenna characteristic is obtained in plural frequency bands of a portable phone or the like. A metal plate 16 having a suitable shape is disposed on an upper surface of a carrier 14 provided on a circuit board 10, and a first and a second antenna elements functioning as inverted-F antennas respectively resonant at a first frequency band and a second frequency band higher than the former are formed by electrically connecting the metal plate 16 to a grounding plate 12 and the circuit board 10 by an earthing terminal 18 and a feed terminal 20, respectively. A third antenna element 24 having a base end electrically connected to the feed terminal 20 and resonant at a third frequency band higher than the second frequency band is provided on a side surface of the carrier 14, ends of the second antenna element and the third antenna element 24 are disposed to be spaced from each other by a distance of 0.

Abstract: A first antenna is movable between a first position pulled out from the communication terminal and a second position accommodated in a mobile communication terminal. A second antenna is built in the communication terminal. A first switch electrically connects only the first antenna with a power feeding circuit via an impedance matching circuit when the first antenna is placed at the first position, and electrically connects only the second antenna with the power feeding circuit when the first antenna is placed at the second position. A second switch grounds the second antenna in cooperation with the first switch, when the first antenna is placed at the second position.

Abstract: A first antenna is movable between a first position pulled out from the communication terminal and a second position accommodated in a mobile communication terminal. A second antenna is built in the communication terminal. A first switch electrically connects only the first antenna with a power feeding circuit via an impedance matching circuit when the first antenna is placed at the first position, and electrically connects only the second antenna with the power feeding circuit when the first antenna is placed at the second position. A second switch grounds the second antenna in cooperation with the first switch, when the first antenna is placed at the second position.

Abstract: A whip antenna is movable between a first position corresponding to a state in which the whip antenna is extended from a casing of the mobile communication terminal, and a second position corresponding to a state the whip antenna is accommodated within the casing. A built-in antenna is disposed within the casing. A power feeding circuit is disposed within the casing. A first matching circuit has a first impedance, through which the power feeding circuit and the whip antenna are electrically connected when the whip antenna is placed at the first position. A second matching circuit has a second impedance which is higher than the first impedance, through which the whip antenna is grounded when the whip antenna is placed at the second position. A switch mechanism is opened so that the built-in antenna is electrically disconnected from the power feeding circuit when the whip antenna is placed at the first position, and closed so that the built-in antenna is electrically connected to the power feeding circuit.

Abstract: A whip antenna is movable between a first position corresponding to a state in which the whip antenna is extended from a casing of the mobile communication terminal, and a second position corresponding to a state the whip antenna is accommodated within the casing. A built-in antenna is disposed within the casing. A power feeding circuit is disposed within the casing. A first matching circuit has a first impedance, through which the power feeding circuit and the whip antenna are electrically connected when the whip antenna is placed at the first position. A second matching circuit has a second impedance which is higher than the first impedance, through which the whip antenna is grounded when the whip antenna is placed at the second position. A switch mechanism is opened so that the built-in antenna is electrically disconnected from the power feeding circuit when the whip antenna is placed at the first position, and closed so that the built-in antenna is electrically connected to the power feeding circuit.

Abstract: A holder is eliminated when installing an antenna to a radio case, the installation operation is simplified, and a feeding mechanism is improved. A slit is provided in a stopper of an antenna so that the outer diameter can be reduced, and the antenna is inserted directly into a cylindrical section of the radio case from the bottom of the stopper. A plate-like feeding spring is provided at the cylindrical section, and is directly attached to a connection point of a circuit substrate of a radio; one end of the plate-like feeding spring pressingly contacts the side of the stopper of the antenna, thereby forming a feeding mechanism.

Abstract: A holder is eliminated when installing an antenna to a radio case, the installation operation is simplified, and a feeding mechanism is improved. A slit is provided in a stopper of an antenna so that the outer diameter can be reduced, and the antenna is inserted directly into a cylindrical section of the radio case from the bottom of the stopper. A plate-like feeding spring is provided at the cylindrical section, and is directly attached to a connection point of a circuit substrate of a radio; one end of the plate-like feeding spring pressingly contacts the side of the stopper of the antenna, thereby forming a feeding mechanism.

Abstract: Conductive tongues project from two places on the axial direction tip of a first antenna element, which projects outwardly from the case of a radio device. When a second antenna element, freely movable in the axial direction, is extracted, the two conductive tongues conductively connect to the base of the second antenna element, and are mutually short-circuited.

Abstract: A conductor is provided from a base to a first fold point at the tip side, and sequentially folded parallel not less than once at the tip side and the base side, forming a first element; the conductor is split at the first fold point and the split conductor is, similarly, sequentially folded parallel not less than once at the tip side and the base side, forming a second element. Then, the effective length from the base to the tip of the first element is set to a quarter of the wavelength of a first frequency, and the effective length from the base to the tip of the second element is set to a quarter of the wavelength of a second frequency.

Abstract: The antenna element (1) of a long conductor is formed with at least one returned portion (1a) arranged substantially in parallel to a longitudinal direction of the antenna element. In practice, a physical length of the antenna element in the longitudinal direction is determined to such a length as to be substantially resonated in a first frequency band, and the at least one returned portion (1a) is formed in such a way as to be resonated in a second frequency band twice higher than the first frequency band on the basis of an electric coupling with the adjacent antenna element.