Author(s)

Toshihisa Kamei¹, Hiromi Shima¹, Takashi Yamamoto², Satoshi Ogino³, Seishiro Ishii⁴

¹Department of Communications Engineering, National Defense Academy, Yokosuka-shi, Japan.
²Department of Materials Science, Osaka Prefecture University, Osaka, Japan.
³Microwave Absorbers Inc., Tokyo, Japan.
⁴KamakamiArchitecture Design and Quantity Surveying Office, Yamagata, Japan.

In this paper, we focus on PHYTOPOROUS, a porous carbon material made entirely from plant-based ingredients, as a new broadband-wave absorber material that acts in the millimeter wave band. We created prototypes of thin rubber-sheet wave absorbers that contain porous carbon (PHYTOPOROUS) made from rice chaff and soybean hulls, which are both agricultural residue products that are generated in large quantities. We investigated the permittivity and reflectance characteristics of this material using the free-space time-domain method. The thin rubber-sheet wave absorber that contained PHYTOPOROUS made from soybean hulls exhibited a frequency band that was approximately 18 GHz wide and centered at 90 GHz. The return loss for this material was greater than −20 dB. This demonstrates that the material provides nearly constant reflection absorption over a wide frequency band.

Microwave Absorber, Millimeter Wave, Porous Carbon Material, Free-Space Method, Reflection Loss

Kamei, T. , Shima, H. , Yamamoto, T. , Ogino, S. and Ishii, S. (2017) Millimeter-Wave Absorption Properties of Thin Wave Absorber in Free Space with New Porous Carbon Material. Wireless Engineering and Technology, 8, 51-58. doi: 10.4236/wet.2017.83004.