| 摘要 |
PROBLEM TO BE SOLVED: To provide a millimeter wave absorber having excellent absorbing performance in a desired frequency in a millimeter wave region and excellent in durability/weatherability. SOLUTION: In the plate type millimeter wave absorber wherein an absorbing layer 1 is laminated on a reflection layer 2, the thickness of the absorbing layer 1 is 1.0mm-5.0mm, and carbon black 1-30 wt.pt is contained in 100 wt.pt of polymer of resin or rubber. In the carbon black, the average grain size of secondary particles consisting of gathered primary particles of carbon atom is not longer than 50nm, the oil absorption value of aggregate consisting of aggregated secondary particles is set so as to be not less than 50mL/100g and the real number of dielectric constant of the absorbing layer 1 in the frequency of 50GHz-90GHz is not less than 3.0. COPYRIGHT: (C)2005,JPO&NCIPI
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