Excitation of highly concentrated spoof surface plasmon polaritons based on LC-resonance theory Asad Aziz, Arsalan Aziz, Mohammad Mahtab Alam and Ahmed M. Galal Eur. Phys. J. Plus, 138 1 (2023) 61 Published online: 21 January 2023 DOI: 10.1140/epjp/s13360-023-03668-0