US Patent 7180458 Antenna and information communication apparatus using the antenna

An antenna including a grounded conductor and a radiating element having a diameter that increases from the top to the bottom in which the top of the radiating element is opposed to the grounded conductor is disclosed. The radiating element of the antenna includes three regions positioned from the top to the bottom, each region having an angle between a side of the radiating element in the region and a center axis of the radiating element, wherein the angles of the three regions satisfy relationship: θ1>θ2 and θ2<θ3 when the angles are indicated by θ1, θ2 and θ3 respectively from the top to the bottom.