Hitachi Metals, Ltd.

Hiroto Ideno

Kenji Hayashi

Hiroyuki Aoyama

Yasunori Takaki

Hiroshi Okamoto

An antenna device comprising an antenna element disposed on a mounting board separate from a main circuit board, a coupling means disposed on the mounting board such that it is electromagnetically coupled to the antenna element, and a frequency-adjusting means disposed on the mounting board such that it is connected to the coupling means, the antenna element comprising first and second strip-shaped antenna elements integrally connected for sharing a feeding point, the second antenna element being shorter than the first antenna element; the coupling means being formed on a dielectric chip attached to the mounting board, and having a coupling electrode electromagnetically coupled to part of the first antenna element. The frequency-adjusting means comprises a parallel resonance circuit comprising a variable capacitance circuit and a first inductance element, and a second inductance element series-connected to the parallel resonance circuit.

Frequency-variable antenna circuit, antenna device constituting it, and wireless communications apparatus comprising it

An antenna device is provided which is capable of saving space, of operating in wide bands (in a multi-band) and of achieving an excellent gain and maintaining non-directivity of vertically polarized waves in each band. The antenna device has a conductor antenna. An end portionon one end side of the conductor antenna is mounted as a power feeding section and an end portionon the other end side of the conductor antennais mounted as an open end terminal. The antenna device also has a base body made of an insulating material which is coupled to one end and other end of the conductor antenna. The base band is coupled in a place where an electric field strength of the conductor antenna having a folded-back portion is increased, thus achieving the wideband and high-gain antenna device.

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Tottori, Japan

Hiroto Ideno