Matsushita Electric Industrial Co., Ltd.

Masaaki Yamabayashi

Koichi Ogawa

Naoki Yuda

Koji Sako

Yoshinobu Nakagawa

Hiroyuki Nakamura

Yoshiharu Abe

Susumu Inatsugu

Kazumine Koshi

Naoyuki Takagi

Kazuji Ota

Yasuhiro Otomo

Naoyuki Yayama

An antenna for portable cellular telephone can adjust each of multiple antenna elements efficiently and independently to a predetermined resonance frequency. A first antenna element and second antenna element are mounted on and anchored to one common base. Terminals for feeding power to the first antenna element and the second antenna element are provided respectively. The terminals are coupled to matching circuits. This structure facilitates separate and efficient adjustment of resonance frequency of the first antenna element and the second antenna element.

Antenna for portable cellular telephone

A narrow and light mobile radio antenna that requires convenient supporting metal fittings provided in a base station is provided. An inner conductor of a coaxial feed line extends upward by a length of &frac14; wavelength from the upper end of an outer conductor. This extended inner conductor forms an antenna element. Outside the coaxial feed line, a &frac14;-wavelength sleeve-like metal pipe made of brass is located with one end connected to the upper end of the outer conductor. On a part of the inner surface of the open end of the metal pipe, an internal thread is formed by tapping. In the open end of the metal pipe, an insulating spacer having an external thread formed around its periphery is inserted. In other words, the insulating spacer is located between the inner wall of the metal pipe and the outer conductor of the coaxial feed line. At the lower end of the coaxial feed line, a coaxial connector for connection with an external circuit is provided.

Mobile radio antenna

A helical coil and a top-helical type antenna using the same, wherein the helical coil has a plurality of either substantially U-shaped or nearly V-shaped branch portions made of a thin metallic sheet material. The branch portions are connected continuously in a manner to place their open ends alternately inversely, and the branch portions alternatively curve toward an obverse side and a reverse side of the metallic sheet to form each turn of the coil. A method for producing the helical coil includes continuously die cutting a member on a belt-shaped strip of electrically conductive metallic sheet, and alternately placing a plurality of either substantially U-shaped or substantially V-shaped branch portions with their open ends inversely. These substantially U or V-shaped branch portions are then connected with each other in the shape of a letter, with connection to the metallic sheet being held only by linkage portions at opposite sides. The helical coil is formed by alternately curving the branch portions of each of the members in a shape of substantially circular arc toward an obverse side and a reverse side of the metallic sheet. A bobbin is formed connecting each turn of the helical coil by either insert-injection molding or outsert-injection molding of electrically nonconductive material on the individual helical coil formed on metallic sheet and subsequently the linkage portions are sheared off of the metallic sheet.

Helical coil, method of producing same and helical antenna using same

Although conventional antennas have characteristics suitable for mobile radio base stations, their vertical dimension is large, and locations of their installation are limited. A radiator for an first upper antenna 32 is arranged in a hollow nonconductive radome 2, using an internal conductor 7a and a metal pipe 10. A radiator for a second lower antenna 34 is arranged in the radome 2, using metal pipes 14 and 15. Two parasitic elements 31 are installed substantially in parallel with the first antenna 32 below a feeding point 9. Two parasitic elements 33 are installed substantially in parallel with the second antenna 34 above a feeding point 13. These allow the tilt angle to be freely set between -10.degree. and +10.degree. by adjusting the parasitic element length and the antenna to be reduced in size.

Growing community of inventors

Tsuyama, Japan

Masaaki Yamabayashi