Matsushita Electric Industrial Co., Ltd.

Kyohei Fujimoto

Yoshio Koyanagi

Yoichi Nakagawa

Masahiro Mimura

Kentaro Miyano

Hisashi Morishita

Junko Yamamoto

Haruhiro Kuboyama

Kazuhiro Hirasawa

A radio terminal device has an antenna element, a coil, a switch, an RF circuit section and a conductive substrate. The switch is used to switch between a case where current distribution exists only in the antenna element and its vicinities and a case where the current distribution exists not only in the antenna element and its vicinities but also in other places. Additionally, the switch is switched in accordance with the usage pattern in which the user uses the radio terminal device (e.g., telephone call and data communication). This allows the transmission/reception to be performed with the antenna polarization and directivity suitable for the usage pattern. Thus, there can be provided a radio terminal device that exhibits a reception characteristic suitable for a respective situation.

Radio terminal device antenna and radio terminal device

In an antenna unit adapted to be incorporated inside a main body of a mobile radio set, there are provided a pair of helical antenna elements ( ), ( ) connected to a balanced feeding line ( ), the helical antenna elements having antenna axes in a direction parallel to a base plate ( ) of the radio set, and being arranged in proximity to the base plate of the radio set at a sufficiently small distance as compared with their wavelength. By conducting a balanced power supply to the helical antenna elements, an electric current component flowing on the base plate of the radio set can be reduced, thus decreasing influence of the human body when the radio set is carried by the human hand. Additionally, the antenna can posses radiation characteristics of both the electric current type antenna and the magnetic current type antenna, and therefore, the receiving performance when the radio set is tiltedly used will be enhanced.

Antenna unit

A small antenna including a dielectric plate, upper and lower conductive plates provided on upper and lower faces of the dielectric plate, respectively, a plurality of conductive reactance posts for connecting, at first positions of the dielectric plate, the upper and lower conductive plates to each other, and a feed point provided at a second position of the dielectric plate such that first and second plane-parallel plate transmission lines separated from each other by the reactance posts are formed by the upper and lower conductive plates.

Small antenna

Growing community of inventors

Kanagawa, Japan

Kyohei Fujimoto