Electrically small antenna with switchless pattern reconfiguration

An electrically small pattern reconfigurable antenna is proposed. It allows adjustment of the radiation pattern by applying a phase shift between its two ports. The structure is a cylinder with λ/5 diameter. Simulated results show good operation at 2.44 GHz and three different radiation patterns are demonstrated by applying three different phase shifts. The antenna's principles of operation and limitations are explained based on the theory of spherical modes.