Abstract: EMI from an operating information handling system is managed by disposing a stirring device in the chassis of the information handling system to mechanically modulate the resonance of predetermined RF signals emitted from processing components within the chassis. For example, a cooling fan disposed in the chassis has a reflective surface formed on its blades so that rotation of the blades mechanically modulates the RF signals. The blades have a depth of at least one-quarter of the wavelength of the RF signal and are coated with a low resistance material, such as steel, aluminum, copper, carbon loaded plastic or a high dielectric ceramic. The fan rotates at the faster of the speed required to provide desired cooling or the speed desired to produce a desired average RF signal amplitude.

Abstract: Information handling system chassis RF shielding is accurately characterized in a repeatable and rapid manner with a stirring device disposed within the chassis. An RF signal from an RF signal source disposed in the chassis emits a more homogeneous and uniform field due to movement of reflective surfaces of the stirring device within the chassis. For example, an RF receiver located outside the chassis measures the RF signal received from the chassis over one or more complete revolutions of the stirring device to provide improved uniformity of the RF field maximized or averaged over each revolution. The reflective surface is interchangeable to support testing of shielding for chassis of different sizes and rotate vertically and horizontally to average out both vertical and horizontal polarization.

Abstract: An information handling system has a printed circuit board with a split power plane having a plurality of sections that may be used for distributing different voltages on a single conductive foil layer of the printed circuit board to components on the printed circuit board. Capacitive coupling of the split power plane sections may be enhanced with a high dielectric fill between the portions.