Experimental study of the high-order exceptional points in a four-state non-Hermitian microwave meta-atoms systemYaqiong Ding, Xiaoyu Liu, Yuanwei Tong and Lijuan DongEur. Phys. J. Appl. Phys., 98 (2023) 62DOI: https://doi.org/10.1051/epjap/2023230155