Patent ID: 8711051
Filing Date: 2014-04-29
Classification: H01Q

Abstract:
1. An antenna device comprising: a feed element being of a length that allows resonance in a specified frequency band; a distributed constant feed line grounded at one end and coupled at another end to the feed element to form a feeding point; a reactive element grounded at one end and coupled at another end to a position a specified distance from the feeding point of the feed line; a first switch disposed between the feed line and the reactive element and used to select whether the feed line and the reactive element are coupled or uncoupled; a parasitic element disposed adjacent to the feed element and being of a length that allows resonance in a frequency band different from the frequency band in which the feed element resonates; and a second switch used to select whether the parasitic element is grounded, the first switch and the second switch being controlled to be in a uncoupled state in a case of transmitting and receiving a signal in a first frequency band, the first switch being controlled to be in a coupled state in a case of transmitting and receiving a signal in a second frequency band, and the second switch being controlled to be in a coupled state in a case of transmitting and receiving a signal in a third frequency band.