Patent ID: 7876271
Filing Date: 2011-01-25
Classification: H01Q

Abstract:
1. An antenna unit applied to a portable radio apparatus, comprising: a circuit board; and a monopole antenna having a first antenna element and a second antenna element both extending in a longitudinal direction of the monopole antenna, each of the first and second antenna elements having a width that extends perpendicularly to the longitudinal direction, the monopole antenna further having a resonance circuit in a middle in the longitudinal direction between the first and second antenna elements, the resonance circuit being connected to the circuit board and configured to cut off a predetermined frequency, wherein the monopole antenna operates as a monopole antenna which responds to a first frequency band; wherein the first antenna element, which constitutes the monopole antenna and is positioned on a connection end side of the resonance circuit, to be connected to the circuit board, operates as a monopole antenna which responds to a second frequency band, and the width of the second antenna element on an open end side of the resonance circuit is set smaller than the width of the first antenna element.