A Novel Method Using a Rectangular Groove to Reduce Far-End Crosstalk in Microstrip Lines Covered with a Dielectric Layer

Microstrip signal lines covered with a dielectric layer are used to reduce far-end crosstalk (FEXT) noise from adjacent lines. When minimizing FEXT noise, the permittivity of the dielectric layer should be higher than that of the substrate. When the permittivity is close to that of the substrate, the thickness of the covering dielectric layer is much larger than that of the substrate. We here present a novel means of reducing FEXT noise in microstrip lines covered with a dielectric layer using a rectangular (R)-shaped groove. When an R-shaped groove is created in the covering dielectric layer or substrate of the microstrip lines, FEXT noise is suppressed in the absence of the above conditions. To analyze the underlying mechanism, we studied the circuit parameters and electric field distribution in the microstrip lines. To confirm the improvements afforded by our methods, we compared simulated and measured data of our new structures to those of other structures.