Study on the Impact of Imbalance between Transmission Lines on Crosstalk: a Novel Perspective of Displacement Current

This paper systematically studies the impact of imbalances between adjacent lines and effects on crosstalk. A novel perspective of displacement current is introduced to analyze and explain the simulated observations. The imbalances caused by coupling between single-single, single-differential, and differential-differential lines are studied and analyzed by considering the near-field coupling through the generated displacement currents. Measurements are conducted for various cases of coupled adjacent lines. An equivalent model considering the variation of displacement current with geometrical parameters is also proposed, and the corresponding coupling coefficients are extracted based on simulations to characterize the impact of imbalances. The methods and results presented in this paper provide useful guidelines for designing high-speed circuit layouts with closely spaced transmission lines.