Patent ID: 7348931
Filing Date: 2008-03-25
Classification: H01Q

Abstract:
1. An unbalanced feeding antenna device which is connected to a radio module performing radio communications with a first radio system using a first band and a second radio system using a second band, comprising: a single antenna element which transmits/receives radio signals in the first and second bands, respectively; first and second matching circuits which are disposed corresponding to the first and second bands, respectively, and match an impedance of the antenna element with an impedance of the radio module; a switching circuit which is disposed between the first and second matching circuits and the radio module; a first filter circuit which is connected between the first matching circuit and the antenna element, passes the radio signal in the first band and also attenuates the radio signal in the second band; and a second filter circuit which is connected between the second matching circuit and the antenna element, passes the radio signal in the second band and attenuates the radio signal in the first band, wherein the switching circuit connects the first matching circuit to the radio module in a period performing the radio communication with the first radio system and connects the second matching circuit to the radio module in a period performing the radio communication with the second radio system.