A circular disc-shaped antenna with frequency and pattern reconfigurable characteristics

This paper presents a novel circular disc-shaped antenna with frequency and pattern reconfigurable characteristics. The antenna consists of a central circular patch and five surrounding fan ring parasitic patches with U-shaped slot. By reconfiguring the depth of the slot, the antenna can operate at two resonant frequencies of 5.63GHz and 5.73GHz, respectively, while maintaining the stability of radiation pattern and impedance bandwidth. The main lobe of each pattern directs to one of five different directions in the plane with the elevation angle of 45 degree by controlling the states of one set of connections between the central patch and parasitic patches. The antenna with compact and simple structure has good performance of impedance matching at two resonant frequencies. The gains of the back lobe and side lobe are both low while the main lobe is high. Considering the pattern gain and beamwidth, the antenna can cover all directions in the elevation plane at each resonant frequency.