A compact dual-band resonator for negative permittivity metamaterial at microwave regime

We report a compact dual-band negative permittivity metamaterial resonator evolved from conventional Z-shaped resonator. The design approach is based on modifying the resonator geometry to raise overall inductance and capacitance in the structure. Numerical simulations and parameter extractions indicate negative permittivity response over microwave frequencies 2.77GHz-3.97GHz and 7.37GHz-9.10GHz. The electromagnetic response and effective medium ratio for metamaterial made of proposed resonator are compared with various other electric resonators to show its superiority. Metamaterial sample is fabricated and free space measurements are performed to validate resonance frequency. The proposed structure is planar, compact and can be scaled at higher THz and optical frequencies for practical applications.