Andreas Weisshaar

CAD-oriented equivalent-circuit modeling of on-chip interconnects on lossy silicon substrate

A new, comprehensive CAD-oriented modeling methodology for single and coupled interconnects on an Si-SiO/sub 2/ substrate is presented. The modeling technique uses a modified quasi-static spectral domain electromagnetic analysis which takes into account the skin effect in the semiconducting substrate. Equivalent-circuit models with only ideal lumped elements, representing the broadband characteristics of the interconnects, are extracted. The response of the proposed SPICE compatible equivalent-circuit models is shown to be in good agreement with the frequency-dependent transmission line characteristics of single and general coupled on-chip interconnects.

Compact folded line rat-race hybrid couplers

A new, compact folded line configuration for rat-race hybrid couplers is proposed. Simple design equations are presented for the single and double C-section folded line structures. The new configuration exhibits a four- to fivefold reduction in footprint as compared to the conventional rat-race configuration. The design is validated both by using the full-wave electromagnetic simulator and with measurement.

Design of compact multilevel folded-line RF couplers

A new design methodology for compact multilevel multiconductor folded-line couplers is presented in this paper. The approach is based on a general network representation of folded-line structures as interconnected coupled lines in a multilayered environment. Simple design equations are presented for compact directional couplers using two-level C-sections, and branch-line hybrids with single and cascaded C-sections. The new folded-line couplers exhibit a significant reduction in foot print compared to the conventional designs. The directional and hybrid folded-line coupler designs are validated by full-wave electromagnetic simulation. Also, a 3-dB branch-line hybrid using three folded-line sections is fabricated. The measured response is found to be in good agreement with the proposed theory.

Design of compact multilevel folded-line bandpass filters

A simple design methodology for compact multilevel multiconductor folded-line bandpass filters is presented in this paper. Several new compact folded-line filter topologies in single, as well as multilevel environments are proposed. Simple closed-form design equations are presented for the extraction of an equivalent coupled transmission line representing the folded-line filter section. The folded-line filter designs are validated by full-wave electromagnetic simulation, as well as by measurement for a four-section maximally flat four-coupled-line bandpass filter. The new folded-line filters exhibit a significant reduction in footprint compared to conventional designs.

Characterization of near- and far-field radiation from ultrafast electronic systems

Accurate and computationally efficient characterization of near- and far-field radiation from a class of microwave, millimeter wave, and ultrafast systems is presented. A numerical technique is utilized which combines the finite-difference time domain method with a spatial transformation, the Kirchhoff surface integral. Included in the analysis are inhomogeneous material parameters, small feature size relative to wavelengths of interest, and the wide-band nature of the radiation. Based on simulation results, a simple model of the radiation from an inhomogeneous structure is developed. Finally, the technique is applied to accurately characterize the radiation from a photoconducting structure.