A Pattern-Reconfigurable Cylindrical Dielectric Resonator Antenna With Three Switchable Radiation Patterns

A pattern-reconfigurable antenna with three switchable radiation patterns is investigated. It consists of a three-layer cylindrical dielectric resonator antenna (DRA) and a parasitic monopole antenna. Its feed network comprises a Y-shaped feedline, a square ring slot, and seven diodes. For the first time, by controlling the operation states of the diodes, the radiation pattern of the antenna can be switched between the omnidirectional, broadside, and unilateral modes. The omnidirectional pattern is obtained by virtue of the parasitic monopole, whereas the broadside pattern can be obtained when the DRA and radiation mode of the feeding ring slot are excited. If the parasitic monopole, DRA, and radiation mode of the slot are all excited, their radiation fields can be superimposed to give a unilateral radiation pattern. The radiated E-field is vertically polarized for all of the three radiation modes. A prototype working in 2.4-GHz industrial science medical (ISM) band was fabricated and tested to verify the idea, and reasonable agreement between the measured and simulated results is observed.