Transient and frequency domain analysis of multiconductor, multi-level microstrips and discontinuities

Multi-level, multi-conductor, planar transmission lines and discontinuities such as those found in high-speed, high-density digital integrated circuits and Microwave (MIC's) and Millimeter-Wave Integrated Circuits (MMIC's) are studied using the Spectral Domain Approach (SDA). The transient analysis of coupling and distortion on multi-level, multi-conductor interconnects is formulated by characterizing the independent propagating modes with the SDA and using a Fourier transform approach to compute the time-domain response. Crosstalk reduction in high-speed, high-density digital interconnects is also discussed, emphasizing the use of substrate-compensated low-coupling structures. Low-coupling structures implemented with symmetric coupled lines, asymmetric lines and multi-line structures are presented to show the applicability of this approach. A closed-form expression for the effective relative dielectric constant of a two-layer microstrip line suitable for the Computer Aided Design (CAD) is derived from data computed with the SDA. The dielectric losses in multi-layer, multi-conductor structures are simulated with both a full-wave approach and an approximate formula that is valid for low-loss structures. Results for slow-wave microstrips lines using Metal-Insulator-Semiconductor (MIS) configuration are given over a wide range of frequency and typical substrate configurations. The SDA is extended to handle three-dimensional simulation of complex planar transmission line structures. This formulation is used to investigate the interactions of discontinuities on different levels in MMIC's, as well as those in digital interconnects...