Three-dimensional printed fractal dielectric-resonator-based broadband microwave absorber

A broadband microwave absorber based on fractal rectangular dielectric resonator (DR) unit is investigated in this paper. The designed absorber can be fabricated with low-cost three-dimensional printing technology, using the high-loss carbon-carrying acrylonitrile-butadiene-styrene (ABS) polymer. To enhance the operating bandwidth, the fractal-shaped rectangular DR unit is used and multi modes are excited. For verify, a prototype of the absorber with 8 x 8 unit cells were fabricated and measured. The results indicate that the absorptivity can achieve greater than 90% within a relative bandwidth of 130% from 3.1 to 14.7 GHz, which covers the whole C-band (4-8 GHz) and X-band (8-12 GHz). In addition, the absorption properties of the absorber at different incident angles were studied.