Taiyo Yuden Co., Ltd.

Hisahiro Yasuda

Takeshi Kosaka

Makoto Inoue

Masao Igarashi

Kenji Takei

Kenji Yoshimori

Kazuhisa Sato

Takashi Amano

Kazuya Maekawa

Hironori Okado

Tatsuya Imaizumi

Naoto Kobayashi

Shinichi Sugiyama

A directional coupler includes: a main line electrically connected between input and output terminals and including a first line, a second line connecting the first line and the input terminal, and a third line connecting the first line and the output terminal; a sub line electrically connected between coupling and isolation terminals and including a fourth line electromagnetically coupled with the first line, a fifth line electromagnetically coupled with the second line, and a sixth line electromagnetically coupled with the third line, the fifth line connecting the fourth line and the coupling terminal, the sixth line connecting the fourth line and the isolation terminal, and a ground conductor, shortest distances between the ground conductor and the first and fourth lines being less than shortest distances between the second, third, fifth, and sixth lines and the ground conductor.

Directional coupler

A balanced filter suitable for a reduction of the filter size. The balanced filter comprises strip-line resonators (SL, SL) constituting resonance electrodes coupled to an unbalanced terminal, strip-line resonators (SL, SL) coupled directly to balanced side terminals and strip-line resonators (SL, SL) coupled to the balanced side terminals through impedance elements (Z).

Balanced filter device

A balanced filter suitable for a reduction of the filter size. The balanced filter comprises strip-line resonators (SL, SL) constituting resonance electrodes on the unbalanced side, strip-line resonators (SL, SL) disposed in adjacently opposed relation to the strip-lines on the unbalanced side and constituting resonance electrodes on the balanced side, strip-line resonators (SL, SL) disposed in adjacently opposed relation to the strip-lines on the balanced side and constituting stage constituting resonance electrodes, and impedance elements (Z) coupling the resonance electrodes on the balanced side to the stage constituting resonance electrodes.

A balun device, a balance filter device, and a wireless communication apparatus are provided. An intermediate electrode is disposed between a balanced resonance electrode and a GND electrode. More specifically, the balun device includes a pair of GND electrodes formed on a dielectric layer, an unbalanced resonance electrode formed on a dielectric layer, and a balanced resonance electrode formed on a dielectric layer. The unbalanced resonance electrode and the balanced resonance electrode are disposed between the pair of GND electrodes by laminating the corresponding dielectric layers. The intermediate electrode is interposed between the balanced resonance electrode and the GND electrode positioned close to the balanced resonance electrode.

Balun device, balance filter device, and wireless communication apparatus

Under circumstances where communication devices such as mobile phones are required to be diversified, laminate filters are required to have attenuation-band characteristics which are steep on both low-frequency and high-frequency sides. The prior-art laminate filter has the problem that an attenuation band is formed only on the low-frequency side or on the high-frequency side. A laminate filter has stripline patterns that are first, second, and third resonant elements disposed on a dielectric layer, a capacitively coupled (C-coupled) pattern disposed between the first and second stripline patterns, an inductively coupled (M-coupled) pattern disposed between the second and third stripline patterns.

Filter circuit and laminate filter

The present invention relates mainly to a small dielectric antenna capable of obtaining a good VSWR characteristic even if it is placed in the vicinity of a grounding pattern when mounted on a circuit board. A dielectric antenna is formed in which a feed point of an antenna elementhaving a resonance frequency set to a first frequency in a first frequency band and a feed point of an antenna elementhaving a resonance frequency set to a second frequency are connected to an external feed terminal, and an open stubconnected to the antenna elementin the vicinity of the feed point. The open stubis provided to enable resonance at each of frequencies to be used while the lengths of the antenna elementsandare shorter than ordinary lengths determined according to the wavelengths of the frequency to be used. Further, even in the case of placement in the vicinity of a grounding conductor patternat the time of mounting on a circuit board, the frequency bandwidth through which a good VSWR characteristic can be obtained in a used frequency band can be extended.

Dielectric antenna

A radio frequency filter having at least two dielectric resonators in juxtaposition, each resonator including a tubular dielectric body. Formed on the dielectric body of each resonator are an inner and an outer conductors and various other conductors including a terminal conductor for connection of the filter to external circuitry. In order to assure positive isolation of the terminal conductors of both resonators from each other, the outer conductors are provided with extensions which intervene between the terminal conductors for preventing then from being capacitively coupled together.

Wave filter having two or more coaxial dielectric resonators in juxtaposition

A radio frequency filter having at least two dielectric resonators in juxtaposition, each resonator including a tubular dielectric body. Formed on the dielectric body of each resonator are an inner and an outer conductors and various other conductors including a terminal conductor for connection of the filter to external circuitry. In order to assure positive isolation of the terminal conductors of both resonators from each other, the outer conductors are provided with extensions which intervene between the terminal conductors for preventing them from being capacitively coupled together.

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Tokyo, Japan

Hisahiro Yasuda