Yokowo Co., Ltd.

Kabushiki Kaisha Yokowo

Tadashi Oshiyama

Hirotoshi Mizuno

Yusuke Suzuki

Katsutoshi Okubo

Seiji Gou

Atsushi Sato

Wasuke Yanagisawa

Takao Kawahara

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 &#xbe; 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 &#xbd; wavelength of the second frequency band.

Multi-band antenna with inductor and/or capacitor

The present invention provides an antenna for multiple bands employing a single antenna element, capable of operating in multiple frequency bands, and ideal for size reduction purposes. One end A of an antenna elementis electrically connected to a feeding pointand intermediate points B and C and the other end thereof is electrically connected via switches SWb, SWc, and SWd to a ground conductor. The electrical lengths of the antenna elementfrom 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 conductorare 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. Thus, the antenna employing the single antenna elementcan operate in multiple frequency bands.

Antenna for a plurality of bands

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.

Multi-frequency antenna

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 platehaving a suitable shape is disposed on an upper surface of a carrierprovided on a circuit boardand 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 plateto a grounding plateand the circuit boardby an earthing terminaland a feed terminalrespectively. A third antenna elementhaving a base end electrically connected to the feed terminaland resonant at a third frequency band higher than the second frequency band is provided on a side surface of the carrierends of the second antenna element and the third antenna elementare disposed to be spaced from each other by a distance of 0.1 wavelength or more of the third frequency band, and the end of the third antenna elementis disposed to be spaced from the grounding plateby a distance of 0.01 wavelength or more of the third frequency band. Besides, the third antenna element may be made resonant at a fourth frequency band higher than the third frequency band, and a matching circuit to perform matching for the third frequency band may be provided.

Broad-band antenna for mobile communication

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.

Antenna device for mobile communication terminal

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.

Antenna device for mobile tele-communication terminal

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.

Antenna for portable radio

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.

Antenna for radio device and radio device

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. Also provided is a folded antenna element, comprising a conductor in a direction from the base to the tip side, the conductor being folded at least once at the tip side and arranged parallel to the direction, is made cylindrical; a rod-like antenna element is provided so as to be freely movable in the axial direction of the folded antenna element; and, in an extended state, the base side of the rod-like antenna element becomes inserted to the tip side of the folded antenna element and is capacitance-coupled thereto by a large coupling capacitance. The effective length of the folded antenna element from the base to the tip is a quarter of the wavelength of the first frequency, and three quarters of the wavelength of the second frequency. In the extended state, the effective length from the base of the folded antenna element to the tip of the rod-like antenna element is a quarter of the wavelength of the first frequency, and three quarters of the wavelength of the second frequency.

Growing community of inventors

Gunma, Japan

Tadashi Oshiyama