Design of a Dual-Band, Electrically Small, Parasitic Array Antenna

A new design of an electrically small parasitic array antenna to obtain dual bands is suggested. The antenna comprises a driver and two directors, where all elements are bent in rectangular shapes to reduce the antenna size. Two resonances nearby each other are achieved by twisting vertical segments into helical shapes, starting from the ground of both directors. The overall volume of the antenna is 18.0 mm (0.099λ)×21.0 mm (0.116λ) ×21.4 mm ( 0.118λ), and the electrical size, kr, is 0.8. The maximum realized gains in the director direction are greater than 8.4 dBi at both resonant frequencies.