Distributed lossy capacitive circuit element with two resistive layers

摘要

A lossy capacitive circuit element, or DC scrubber, is printed on a circuit substrate and absorptively filters high frequency signals in circuit modules. A top conductor of the DC scrubber is separated from a ground conductor by a layer of high dielectric material. A resistive layer, positioned either above or below the top conductor absorbs high frequency signals applied to the top conductor while the dielectric layer shunts the signals to the ground conductor. Alternatively, a pair of DC scrubbers are stacked vertically to configure the lossy capacitive structures in parallel. Signal isolation provided by the DC scrubber and the stacked DC scrubber enables inexpensive DC interfaces to be used in the circuit modules.