Determining the Resistivity of Resistive Sheets Using Transmission Measurements

摘要

In September 2005, radar cross section (RCS) measurements were made of resistive sheets, or R-cards, wrapped around a polystyrene foam cylinder to compare with a newly developed theoretical RCS prediction technique. The resistivities of the R-cards were initially measured with a direct current (DC) four-point probe. When the RCS measurements were compared to the theoretical predictions, it became clear that DC resistivity alone is not sufficient to accurately predict the scattering from an R-card. This thesis presents alternating current (AC) methods for determining the resistivity of an R-card. Both freespace and waveguide techniques are presented. Experimental verification of the techniques is performed using two R-cards with DC resistivities 892 & No. 937;/sq and 64 & No. 937;/sq. The techniques are compared intraand inter-measurement apparatus. An error analysis is also performed to demonstrate the sensitivity of the techniques to errors in the measurements of the thickness or the permittivity of the support backing.