A Synthesis Process for Microwave Absorber Design Based on Pyramidal Absorbers

Pyramidal absorbers used in anechoic chambers are one of the primary components in the measurement and performance assessment of antennas. To achieve absorbers with predefined specifications, optimum design and best material selection is an indispensable requirement. The proper material for fabricating an absorber has often been selected based on heuristic and intuitive approaches. Here, we introduce a process to find the most suitable electromagnetic material properties for achieving a target performance in an absorber with certain geometry. The method is based on using full-wave numerical simulations to obtain lines of equal absorption in the complex plane for material permittivity at certain frequency points. By locating the permittivity of available materials in the obtained plots, the best material to fabricate the absorber of interest is found. The example of 60-inch absorbers is taken into account, and the best carbon loading for fabricating such an absorber is gained through the developed process.