US Patent 7616158 Multi mode antenna system

An antenna system comprising a first antenna element, a second antenna element, the first and second elements defining at least in part a slot element, an active switching network in communication with one or both of the first and second antenna elements, the switching network operable to cause the antenna system to resonate in each of two modes: a first mode wherein the first element resonates at a first set of frequencies, and the first element and a second element resonate together at a second set of frequencies; and a second mode wherein the first element resonates at the first set of frequencies, and the slot element resonates at a third set of frequencies.