  Dielectric materials with tunable permittivity are highly desirable for
wireless communication, radar technology. However, the tunability of dielectric
properties in the microwave frequency range and higher is an immense challenge
for conventional materials. Here, we demonstrate a giant magnetodielectric
effect in the GHz region in a metamaterial based on ferrite unit cells. The
effect is derived from the coupling of the ferromagnetic resonance and the Mie
resonance in the ferrite unit cells. Both the simulated and experimental
results indicate that the effective permittivity of the metamaterial can be
tuned by modifying the applied magnetic field, and a giant magnetodielectric
effect, [{\epsilon}'(H) - {\epsilon}'(0)]/{\epsilon}'(0) = 15000 % at 11.284
GHz, is obtained. This mechanism offers a promising means of constructing
microwave dielectrics with large tunable ranges and considerable potential for
tailoring via a metamaterial route.
