To provide a small-sized antenna especially operating in three or more multiple modes, a manufacturing method for the antenna, and a portable radio terminal to which the antenna is mounted, for embodying an inexpensive and small-sized multimedia radio terminal.
An antenna 1 comprises: a ground conductor 2 having ground potential; a single feeding point 7 whose one end is a part of the ground conductor 2; and a plurality of transmission lines each of which radiates an electromagnetic wave in three modes and of three frequencies into space after receiving high-frequency power supplied to the feeding point 7 as input. Each of the transmission lines comprises: a transmission line 41 whose one end and another end are connected to the feeding point 7 and a branch point 31, respectively; a transmission line 42 connected between the branch point 31 and a branch point 32; and transmission lines 51, 61, and 62 connected to the above branch points. Each length of the transmission lines is set so that impedance matching is achieved at the feeding point 7 for a plurality of frequencies. The antenna 1 is formed of one undivided metal board.
OGAWA TOMOYUKI
IKEGAYA MORIHIKO
FUKUCHI KEISUKE
| US6606071B2 | 2003-08-12 |