Recent trends in CAD tools for microwave circuit design exploiting space mapping technology.

摘要

This thesis contributes to the development of novel methods and techniques for computer-aided electromagnetics (EM)-based modeling and design of microwave circuits exploiting space mapping (SM) technology.; Novel aggressive space mapping (ASM) algorithms exploiting sensitivity information from the fine and the coarse models are developed. The modified algorithm enhances the parameter extraction (PE) process by not only matching the responses of both fine and coarse models but also corresponding gradients. We also used the gradients to continuously update a suitable mapping between the fine and coarse spaces. The coarse model combined with the established mapping is considered a "surrogate" of the fine model in the region of interest. It can be used in statistical analysis and yield optimization.; A comprehensive review of SM technology in engineering device modeling and optimization, with emphasis in Radio Frequency (RF) and microwave circuit optimization, is introduced in this thesis. Significant practical applications are reviewed.; We explore the SM methodology in the transmission-line modeling (TLM) simulation environment. We design a CPU intensive fine-grid TLM structure utilizing a coarse-grid TLM model with relaxed boundary conditions. Such a coarse model may not faithfully represent the fine-grid TLM model and it may not even satisfy the original design specifications. Hence, SM techniques such as the aggressive SM will fail to reach a satisfactory solution. To overcome the aforementioned difficulty, we combine the implicit SM (ISM) and output SM (OSM) approaches. As a preliminary PE step, the coarse model's dielectric constant is first calibrated. If the response deviation between the two TLM models is still large, an output SM scheme absorbs this deviation to make the updated surrogate represent the fine model. The subsequent surrogate optimization step is governed by a trust region strategy. Because of the discrete nature of the TLM simulator, we employ an interpolation scheme to evaluate the responses, and possibly derivatives, at off-grid points with a dynamically updated database system to avoid repeatedly invoking the simulator.