RF shielding characteristics of an HTS plate: RF shielding improvement by changing the surface area of BPSCCO plate

The contamination of the environment by electromagnetic pollution has been increasing with the employment of more electronic devices. Therefore, the use of electromagnetic shielding has increased in order to improve environmental conditions. A high-critical temperature superconductor which employs perfect diamagnetism, is an ideal material for use as a radio frequency (RF) shield. In the present paper, the RF magnetic shielding effect SDH was systematically measured by changing the surface area of the Bi-Pb-Sr-Ca-Cu-O (BPSCCO) plate. It was found that the values of SDH for a BPSCCO plate with a surface area of 225 cm(2), at frequencies of 1 and 10 MHz, were improved by approximately 45 and 30 dB, respectively, over those of a 25 cm(2) plate. In addition, the magnetic SDH for the 25 cm(2) BPSCCO plate was improved by the superposition of similar BPSCCO plates over the original BPSCCO plate; termed the multi-layered plate system. The value of SDH for a four-layered plate system at the frequency of 10 MHz was, consequently, improved by approximately 20 dB greater than that of the single-BPSCCO plate. Also shown are the important criteria for the design of effective RF shielding vessels for improving the electromagnetic environment. (C) 2002 Elsevier Science B.V. All rights reserved.