Wideband Reconfigurable Rolled Planar Monopole Antenna

A novel technique to reconfigure the frequency range of a planar monopole antenna is presented. By adjusting the degree of spiral tightness, a shift of the resonances is achieved. The proposed antenna is capable of covering the frequencies in the range from 2.9 GHz to 15 GHz, depending on the degree of spiral tightness. The antenna yields a high efficiency across the full operating bandwidth. Radiation patterns show good omnidirectional features in all primary cuts and remain relatively stable with the change of antenna configuration, so that it is a remarkable candidate for indoor or mobile applications where a large frequency range and omni-directional radiation are required.