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.
References
[1]
International Telecommunication Union (2014) Recommendation, ITU-R M.2057-0. System Characteristics of Automotive Radars Operating in the Frequency Band 76-81 GHz for Intelligent Transport Systems Applications.
[2]
Yokoyama, S. (2002) Agricultural Residue. In: The Japan Institute of Energy, Eds., Biomass Handbook, Ohmsha, Tokyo, 59-60. (In Japanese)
[3]
Okabe, T. (1996) Wood Ceramics (In Japanese). Uchida Rokakuho Inc., Tokyo, 42.
[4]
Iizuka, H., Fushiani, M., Ohtsuka, M., Okabe, T., Saito, K. and Hokkirigawa, K. (1996) Mechanical Properties of Porous Carbon Materials i.e. Woodceramics. Journal of Materials Science Letters, 15, 1770-1772. https://doi.org/10.1007/BF00275337
[5]
Iizuka, H., Fushitani, M., Okabe, T. and Saito, K. (1999) Mechanical Properties of Woodceramics: A Porous Carbon Material. Journal of Porous Materials, 6, 175-184. https://doi.org/10.1023/A:1009691626946
[6]
Iizuka, H., Katoh, G., Igarashi, K., Shikano, S. and Takahashi, T. (1999) Mechanical Properties of a Porous Carbon Materials Made from Rice Bran (In Japanese). Materials, 49, 625.
[7]
Gibson, L.J. and Ashby, M.F. (1993) Ohtsuka, M., Trans. Cell Structures. Uchida Rokakuho Inc., Tokyo, 17.
[8]
Iizuka, H. (2010) Development of Porous Carbon Materials Utilizing Macroscopic Cellular Structure of Agricultural Residues (In Japanese). Network Polymer, 31, 233-239.
[9]
Kurihara, H., Nishikata, A., Higashida, Y., Takahashi, T. and Hashimoto, O. (2004) A Study on Measurement Method for Reflectivity of Electromagnetic Absorbers in Millimeter Waves (Part 1)—Standardization of Free Space Method By Using Horn Antennas. Technical Report of IEICE, EMCJ2004-31, 33-40.
[10]
Nishikata, A. (2005) About the Effect of Specimen Dimensions, Measurement Distance and Beam Convergence on Measurements of Amount of Reflectance of Wave Absorbers in the Free Space Method (In Japanese). The Journal of the Institute of Electronics, Information, and Communication Engineers, 88, 943-955.
[11]
Ghodgaonkar, D.K., Varadan, V.V. and Varadan, V.K. (1990) Free-Space Measurement of Complex Permittivity and Complex Permeability of Magnetic Materials at Microwave Frequencies. IEEE Transactions on Instrumentation and Measurement, 39, 387-394. https://doi.org/10.1109/19.52520
[12]
Kashihara, K., Fujita, N., Hashimoto, H., Ijiri, Y., Hosotani, K., Mitsui, T. and Kudo, T. (2002) Development of the Sheet-Type Electromagnetic Wave Absorber for ETC/DSRC. Mitsubishi Cable Industries Review, 99, 69-77.
