Concrete ingots covered with interdigital FSS screens as broadband microwave absorbers

Abstract

This study investigates the construction and measurement of broadband microwave absorbers constructed of ‐shaped/comb‐shaped interdigital frequency selective surface (FSS) screens and concrete ingots to enhance frequency response. By applying the comparison decrement method, reflectivity (R) is determined from the return loss of the absorber and the conducting surface, such that R can recognize the characteristics of microwave absorbers. Experimental results indicate that 69.8% of the bandwidth's frequency responses are below ‐10dB when using copper concrete ingots, and 66.1% are below ‐10dB when using fiber concrete ingots in perpendicular polarization (A-) to the π‐shaped FSS absorber. Using the same measurements, 71.6%, and 66.1% of the bandwidth percentage are below ‐10dB with copper and fiber concrete ingots, respectively, for comb‐shaped FSS absorbers in the C‐band applications.