We experimented on the reflective attenuation properties of Bi 2223 superconductor against electromagnetic waves. Sample was prepared as a pellet(32mmφ×2mm, or 32mmφ×5mm) which consists of the superconductor with the average particle size of 50μm or below and epoxy resin. The wt% proportion of the superconductor and epoxy resin was changed to some extent.
The pellet was irradiated by the electromagnetic wave in the ranges from 10.0 to 11.0 GH2 (X band) and from 20.0 to 26.0 GHz (K band) at 290 K and 77K to measure its reflective intensity by using vector network analyzer.
The attenuation value defined in the experiment as a difference between reflective intensity of the sample and that of the same size copper plate gave the maximum attenuation of 60 dB at 10.5 GHz for X band and that of 37 dB at 23.5 GHz for K band.
The maximum attenuations of 52.7 dB at 10.7 GHz and 63.3 dB at 25.2 GHz were obtained for the average particle size of 170μm at 80wt% content although no significant attenuations were observed for the particle size of 270/um at the same content.
Such attenuation properties will be understood in terms of a kind of percolation mechanism.
