Crosstalk mitigation in dense microstrip wiring using stubby lines

As the demand for low-cost electronic systems increases, reducing printed circuit board (PCB) layer count becomes highly desirable. But layer count reduction often limits the PCB routing layer options of high-speed input/output (I/O) signals, making it more difficult to meet the next-generation product's performance targets. For example, using densely wired microstrip routing on a PCB helps reduce layer count, but microstrip routing suffers from performance degradation due to increased far-end crosstalk (FEXT). Stub-alternated lines (“stubby lines”) have been proposed to reduce or eliminate FEXT. In this paper simulation results are presented showing improved memory bus performance on densely routed microstrip channels implemented with stubby lines.