In this paper, an enhanced adaptive frequency sampling algorithm for robust electromagnetic (EM) modeling and computer aided design (CAD) is proposed. The algorithm is based on rational interpolation, which leads to more accurate RF/microwave models as compared to other existing interpolants, e.g. spline. Starting with a minimal number of support points i.e. EM data and with lowest-order rational functions, the algorithm systematically produces a rational function model, which meets a user-specified accuracy. In each stage of the algorithm, additional poles and/or zeros are added, and new support points are adaptively selected based on a statistical criterion. The algorithm distinguishes critical regions of an EM component's behavior that need to be densely sampled and uses relatively fewer data in other regions. The advantages of the proposed algorithm are shown via RF/microwave examples.

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A new adaptive multi-dimensional RF/microwave modeling algorithm based on rational interpolants is proposed. For the first time, the algorithm integrates rational functions, genetic concepts, and frequency mapping into a unified CAD tool, which facilitates accurate and fast EM based RF/microwave modeling. Given an RF/microwave modeling problem, highly non-linear and relatively less nonlinear model inputs are distinguishable. The algorithm consists of two phases. Starting with a minimal number of EM data and with lowest-order rational functions, Phase 1 systematically produces a sub-model with highly non-linear inputs alone. In Phase 2, an initial overall model is first constructed based on the above sub-model. A hybrid mapping then fine-tunes the initial model to capture the RF/microwave tendencies w.r.t. the less non-linear inputs. The algorithm is illustrated through a practical example.

In this paper, we propose a new space-mapping based CAD modeling methodology for modeling temperature characteristics of combline resonators. With the aid of two commercial simulation tools, namely Ansoft HFSS and Agilent ADS, this methodology generates accurate temperature models of combline resonators. The method is generic i. e., it is capable of generating corresponding models for a variety of resonator structures including the mushroom and straight, using only one frequency sweep in HFSS. Fine EM simulations from HFSS are used to create an ultra-fast model in ADS, which is extremely useful to RF/microwave designers.