Negative-index dispersion and accidental mode degeneracy in an asymmetric spoof–insulator

Negative-index dispersion and accidental mode degeneracy in an asymmetric spoof–insulator–spoof waveguide

Tian Li-li¹, Liu Jian-long¹, Zhou Ke-ya¹, Gao Yang², Liu Shu-tian^{1, †}

(color online) (a) Asymptotic frequencies of the symmetric-like and anti-symmetric-like modes as a function of s. (b) Dispersion relation for the asymmetric SIS waveguide with s = 0.283d. Insets in panel (b) are the H_z distributions of the coupled SSPPs on a unit cell of the asymmetric SIS waveguide at 56.25 GHz.