A study on the microwave absorbing honeycomb core embedded with conductive periodic patterned surfaces for the effective dielectric constant

Periodic patterned surfaces can provide effective dielectric constants to the microwave absorbing honeycomb partition wall depending on the size of the pattern. A characteristic study was conducted for a honeycomb-shaped absorber based on the geometric configurations and material properties. The range of the relative permittivity for increasing the absorption bandwidth of the absorber was determined through a parametric study. The imaginary term of the relative permittivity and depth of the wave propagation direction had a significant impact on the bandwidth of the absorber. Moreover, the materials patterned with carbon black- and graphite-based conductive inks using the screen-printing method were bonded to each other at intervals and stacked to form a honeycomb shape. Several absorber specimens were fabricated, and their absorption capabilities were measured using a free-space measurement system. Based on the results, the utility of a film-based honeycomb absorber that can continuously maintain broadband absorptivity was verified.