Mitigation of Passive Intermodulation on Planar Microstrip Circuits with Distributed Current-Driven Nonlinearities

This paper presents a simple technique for effective mitigation of passive intermodulation generated in planar microwave circuits fabricated on commercial printed circuit board laminates. The proposed procedure is based on covering the edges of a microstrip lines with a material of a high dielectric constant, which reduces the electric field intensity (displacement field) and, hence, nonlinear distortions due to high current density . The obtained results indicate that proper choice of electrical and geometrical parameters of the coating dielectric material result in a significant mitigation of passive intermodulation, while small-signal scattering parameters of the measured circuit remain constant.