Optimization of resistive loading of EMI/EMC near field probe

Abstract

Near field studies must be carried out to insulate printed circuit boards and other circuits entirely from outer space. It can be achieved by utilizing the screen properly. These studies must always be made in the near field. The best way known to sense Radio Frequency energy is using a proper loop antenna. The loop probe can be used both as a transmitter and a receiver. If it is loaded resistively, desired flat response between low and high cut off frequency can be obtained. To get accurate results, its physical and electrical parameters must be chosen properly. The most important electrical parameter is inductance of such a loop conductor. Common inductance equations are in general form and they are derived for general calculations. However, loop probes have narrow physical range; they have diameters of a few-centimeters, a few-turn, and have a very thin conductor. So, a certain equation can be derived more accurately. It can be achieved by using conventional empirical derivations or by using modem optimization techniques. (C) 2004 Elsevier B.V. All rights reserved.