Patent attributes
An antenna structure includes a capacitance-rendering portion located between an open end portion of a feed radiation electrode and a ground portion. A switch for changing the capacitance between the open end portion of the feed radiation electrode and the ground portion rendered by the capacitance-rendering portion is provided. When the capacitance between the open end portion of the feed radiation electrode and the ground portion is increased by the capacitance-rendering portion, a resonant frequency in the fundamental frequency band, caused by the antenna operation of the feed radiation electrode, is reduced corresponding to the increased amount of the capacitance. When the capacitance between the open end portion of the feed radiation electrode and the ground portion is decreased by the changing operation of the capacitance-rendering portion, the resonant frequency in the fundamental frequency band is increased corresponding to the decreased amount of the capacitance.
