A novel broadband absorber using the fractal tree structure is presented in this paper, which consists of three metallic layers separated by two dielectric substrates. Five metallic vias connect these three layers which make the whole structure like a two order fractal tree. Simulated and measured results show that this absorber can provide a high absorptivity level from 4.98 to 12.58 GHz, equivalent to a relative absorption bandwidth about 87%. Further investigations show that this wideband absorption can be attributed to the multi-eigenmodes and lower quality factor of the fractal tree structure.
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