Z. Fneish, H. Ayad, M. Kadi, J. Jomaa, and G. Faour "Curved Pyramidal Metamaterial Absorber: From Theory to an Ultra-Broadband Application in the [0.3 – 30] GHz Frequency Band", Advances in Science, Technology and Engineering Systems Journal, vol. 6, no. 2, pp. 29–35, 2021, doi: 10.25046/aj060204.