| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an antenna system, available for a portable radio communication apparatus, which has small variation in antenna gain even when the portable radio communication apparatus is held in a hand and can measure the distance between a measurement point and the antenna system based upon reception intensity of a radio wave. <P>SOLUTION: The antenna system has a micro loop antenna 11 formed nearly perpendicular to a mount surface of a circuit board 2, a capacitor 5 component connected in series on a conductive line constituting the micro loop antenna 11, a ground pattern 6 formed on the mount surface of the circuit board 2, and a radio circuit unit 12 mounted on the circuit board. A feed point P1 for the micro loop antenna 11 and a grounding point P2 of the micro loop antenna 11 are made symmetrical with respect to the series-connection point P2 of a capacitor 5 to decrease the rate of a dipole mode current I<SB>2</SB>flowing to the ground pattern 6 to a micro loop mode current I<SB>1</SB>flowing to the micro loop antenna 11, thereby stabilizing the antenna gain of the micro loop antenna 11. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
