  We demonstrate a nonlinear metamaterial in microwave frequency regime with
hysteresis effect and bistable states, which can be utilized as a remotely
controllable micro second switching device. A varactor loaded split-ring
resonator (SRR) design which exhibits power and frequency dependent broadband
tunability of the resonance frequency for an external control signal is used.
More importantly, the SRR shows bistability with distinct transmission levels.
The transition between bi-states is controlled by impulses of an external pump
signal. Furthermore, we experimentally demonstrate that transition rate is in
the order of microseconds by using a varactor loaded double split-ring
resonator (DSRR) design composed of two concentric rings.
