Investigations on Crosstalk Reduction in Coupled Microstrip Transmission Line

Modular technologies, an integral part of our electronics and electrical systems consists of closely spaced coupled microstrip transmission lines and associated circuitries. This gives rise to crosstalk which is of great concern to the PCB designers as it significantly affects the system performance, hampers signal integrity, and leads to power loss considerably. This paper provides a low-cost solution for reducing crosstalk for commercial systems using a foam layer sandwiched between the circuit layer and the bottom layer with metallic ground plane. A detailed parametric analysis is carried out to obtain a feasible solution to the problem of crosstalk. The simulation as well as measurements are performed both in frequency and time domains for the proposed configuration and compared to examine the cross talk and signal integrity characteristics. It is found that a foam layer inducted between the circuit and the bottom dielectric layer with the metallic ground plane reduces the crosstalk and improves the signal quality. Moreover, the proposed configuration does not require any alteration in the design of the closely spaced transmission lines and can be integrated easily with the existing design.