Non-uniform PCB traces with prescribed frequency bands for improved crosstalk immunity

In this work, a new design approach for realizing printed circuit board (PCB) trace configuration with continuous impedance perturbation to reduce crosstalk in PCB interconnects is investigated. The purpose is to reduce far-end crosstalk without incorporating additional PCB components in order to modify the reactive couplings between the adjacent traces, however at the expense of the available frequency band. This is achieved by replacing a uniform victim trace on a PCB with a continuously varying-impedance trace that exhibits a lowpass filter frequency characteristic. A simplified design approach of the proposed trace impedance profile which is governed by a truncated fourier series is presented. The proposed trace shows better crosstalk reduction results compared to conventional intervening guard trace schemes. Several configurations were designed, implemented, and tested to demonstrate the advantages of the underlying principle.