Patent ID: 7193568
Filing Date: 2007-03-20
Classification: H01Q

Abstract:
1. An antenna device comprising: a first grounded conductor; an antenna element mounted on the first grounded conductor via an insulator; a pair of second grounded conductors with the first grounded conductor interposed therebetween; an inclination detection unit which detects an inclination of the antenna element; an inverting circuit which inverts an output of the inclination detection unit; a first diode connected between one of the pair of second grounded conductors and the first grounded conductor; and a second diode connected between the other of the pair of second grounded conductors and the first grounded conductor, the output of the inclination detection unit being applied to one of the pair of second grounded conductors, with an output of the inverting circuit applied to the other of the pair of second grounded conductors, the operations of the first and second diodes being controlled depending on the output of the inclination detection unit, and directivity of the antenna element being changed by adding the second grounded conductor to the first grounded conductor or canceling the addition thereof.