Electrically small antenna elements using negative permittivity resonators

We show how resonators composed of negative permittivity materials can form the basis of effective small antenna elements. A quasi-static analysis of the resonant properties of a sub-wavelength negative permittivity sphere predicts that such a resonator will have a Q-factor that is only 1.5 times the Chu limit, making it an ideal candidate for use as an electrically small antenna. Finite element simulation is used to demonstrate how such an antenna can be constructed by coupling the resonator (a half-sphere above a ground plane) to a 50 ohm coaxial transmission line in order to form an impedance-matched radiating structure. The resulting antenna has a ka