Tunable bandpass filters based on one-dimensional bilayer period structure composed of single-negative materialsX.H. Deng, J.T. Liu, J.R. Yuan, T.B. Wang and N.H. LiuEur. Phys. J. B, 85 7 (2012) 232DOI: https://doi.org/10.1140/epjb/e2012-30038-x