A compact dual, triple band resonators for negative permittivity metamaterial

We report, two different dual and triple-band designs of single negative meta-atoms based on combination of individual Z-shaped and S-shaped inclusions. The multi-band responses for proposed resonators are obtained based on combination of individual resonant structures which exhibit electric resonances at different frequencies in microwave region. Numerical simulations and parameter extractions using retrieval method for normally incident wave demonstrate negative permittivity response over frequencies 3.27-4.5 GHz and 7.37-9 GHz for metamaterial made of dual-resonant meta-atom (DRMA). Further, metamaterial made of modified version i.e., triple-resonant meta-atom (TRMA) has negative values for permittivity over frequencies 2.79-3.5 GHz, 6.4-7.5 GHz and 8.93-11.0 GHz. The magnitude of reflection and transmission coefficient obtained from numerical simulations are further validated with microwave free space measurements. The equivalent circuit model developed for TRMA is validated with numerically simulated results. The effective medium ratio (λ0/p) for proposed resonators is compared with various other metamaterial resonators to indicate compact nature. The proposed DRMA/TRMA resonators can find applications in performance improvement of multiband devices such as antennas, antenna arrays, filters and in realization of microwave sensors, detectors at microwave frequency regime.