Ultra Broadband Curved Pyramidal Absorber Metamaterial in the UHF/SHF Region

A microwave ultra-broadband polarization independent metamaterial absorber in the UHF/SHF frequency bands is presented. As a first task, we enhanced the relative absorptive bandwidth of the conventional pyramidal absorber making the altitude curved. Such modification increased the Relative Absorptive Bandwidth (RAB) from 36% to 70.45% with an absorptive level greater than 90%. In addition, we focused on another task by which we aimed to have an ultra-broadband of absorption in UHF/SHF region. In this manner, we present the new metamaterial absorber prototype, with a total thickness of (12.7) cm, consisting of 35 curved resonant layers of different sizes. Numerical simulations show an enhanced design with an absorption band from 0.3 GHz to 30 GHz. Both prototypes are tested using the numerical simulator High Frequency Structure Simulator (HFSS).