THIN POLYANILINE FILMS IN EMI SHIELDING

Electromagnetic interference shielding efficiency has been measured fo r highly electrically conducting Polyaniline-Camphor Sulfonic Acid. Th e polymer is spin coated from m-cresol solution on an electrically ins ulating substrate as a 1-30 mu m thick layer having a conductivity of 10-100 S/cm. The shielding efficiencies (SE) for these electrically th in polyaniline films have been measured in the near-field with a dual- chamber box and in the far-field with a transmission line method in th e frequency range 0.1 - 1000 MHz. The measurements show that SE depend s primarily on the surface resistance both in the far-field and the ne ar-field. An additional effect greater than or equal to 10 dB is seen when the two layer structure is measured in the near field. By using l ayer structures, the SE is >40 dB up to ca. 100 MHz in the near-field and 39 dB at 1 GHz in the far-field.