PURPOSE: To obtain a radiowave-absorbing body having excellent characteristics by forming a plurality of tapered protruding ridges or projections on one surface of a mat shaped fiber assembly.
CONSTITUTION: In a radiowave absorbing body, polar polymer of nylon and the like is coated with carbon. The carbon and polyvinyl chloride are dissolved and dispersed in toluene. The solution is splayed and applied, and the carbon coating is provided. Entangled fibers are bonded with a bonding agent. A mat shaped fiber assembly incorporates at least two fibers having at least two kinds of thicknesses, e.g., 0.1mm and 1mm. The kinds of the thicknesses are increased for radiowave absorption in a broad range. The thickness of the carbon coating is 10-30μm. Tapered protruding ridges or projections are provided on one surface of the met so that the tips are sharp. The projections are directed toward the radiowave input direction (a). At this time, it is considered that the conductivity is changed apparently in the thickness direction in the absorbing body. The conductivity is low at the incident surface. The conductivity becomes higher toward the inner part. Since the conductivity at the incident surface is low, the difference between said conductivity and that of air is small. The amount of the radiowave which is reflected from the incident surface is decreased, and the excellent radiowave absorbing characteristics can be achieved.
KITA TOSHIO
HAYASHI YUICHI
OUCHI YUTAKA
KAWANAKA TERUAKI
NAKAMURA YUTAKA
