Development and evaluation of wideband negative response in ultra-thin polygon metamaterial Atipriya Sharma, Harbinder Singh, Amit Gupta and Ahmed Jamal Abdullah Al-Gburi Eur. Phys. J. B, 97 5 (2024) 61 Published online: 14 May 2024 DOI: 10.1140/epjb/s10051-024-00692-6