Measurement of induced current in loaded loop antennas

Classical formulations of coupling theory are based on narrow band, steady state, frequency domain techniques, with consideration given mainly to linear loads and small signal analyses. For high voltage, short pulse coupling such theories become difficult to use. The authors outline an alternative method of analysis and measurement based on integral solutions of Maxwell´s equations in the time domain. The authors use the integral equation formulation to consider the important case of coupling to loop structures and present experimental and theoretical results for the current induced in circular loops loaded by linear and nonlinear loads. They are specifically interested in coupling to electrically large loops, which in the time domain implies pulse lengths of the order of or less than loop diameter. The main motivation for this work is to assess the coupling of subnanosecond pulses to loops on printed circuit boards designed for use in computer and control systems