Design of miniaturized, low-loss and flexible multi-band metamaterial for microwave application

In this paper, a novel miniaturized low-loss metamaterial unit cell structure, called circular spiral split ring resonator (CSSRR), operating at microwave frequency regime is introduced. The miniaturization is realized with inductive loading by increasing the length of metallic spiral strips inside the structure. Due to inductive loading, the effective inductance-to-capacitance ratio, L/C, is increased as a consequence, low-loss behaviour is also obtained along with the compactness. Despite of miniaturization and low loss, the introduced structure exhibits multi-resonance property with two distinct epsilon-negative (ENG) regions and one mu-negative (MNG) region over the X, Ku, and K microwave frequency bands. Particularly, the low-loss behaviour is observed for all three resonance frequencies of the proposed structure. Furthermore, the presented metamaterial is flexible and provides stable characteristics to bending as well as twisting effect.