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Rapid design closure of microwave components by means of feature-based optimization and adjoint sensitivities

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2018年第2期28卷

作者： Koziel, Slawomir Bekasiewicz, Adrian Reykjavik Univ Sch Sci & Engn Engn Optimizat & Modeling Ctr IS-101 Reykjavik Iceland Gdansk Univ Technol Fac Elect Telecommun & Informat PL-80233 Gdansk Poland

In this article, fast design closure of microwave components using feature-based optimization (FBO) and adjoint sensitivities is discussed. FBO is one of the most recent optimization techniques that exploits a particular structure of the system response to flatten the functional landscape handled during the optimization process, which leads to reducing its computational complexity. When combined with gradient-based search involving adjoint sensitivities, the design cost becomes even lower, allowing us to find the optimum design using just a few electromagnetic (EM) simulations of the structure at hand. Here, operation and performance of the algorithm is demonstrated using a waveguide filter and a miniaturized microstrip rat-race coupler (RRC). Comparative studies indicate considerable savings that can be achieved even compared with adjoint-based gradient search. In case of RRC, numerical results are supported by experimental validation.

关键词： adjoint sensitivities compact circuits design closure EM-driven design feature-based optimization microwave design microwave filters

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Equivalent Circuit Modeling of On-Chip Inductors using feature-based optimization 16

Equivalent Circuit Modeling of On-Chip Inductors using Featu...

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16th IEEE Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF)

作者： Shilimkar, Vikas S. Kabir, Humayun Zhang, Lei Mahan, Adam Kim, Kevin Freescale Semicond Tempe AZ 85284 USA

ISBN: (纸本)9781509016884

We propose a method for extraction of equivalent circuit model for on-chip spiral inductor. The method is based on optimization of circuit elements based on feature points extracted from frequency dependent response. The accuracy of the method is validated by extracting a set of models from electromagnetic simulations of on-chip rectangular spiral inductors. An excellent agreement is achieved between the model and simulation data.

关键词： equivalent circuit model feature-based optimization on-chip spiral inductors

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Expedited Design of Dual-Band Antennas Using feature-based optimization

Expedited Design of Dual-Band Antennas Using Feature-Based O...

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European Conference on Antennas and Propagation

作者： Slawomir Koziel Adrian Bekasiewicz Leifur Leifsson Engineering Optimization & Modeling Center Reykjavik University 101 Reykjavik Iceland Department of Aerospace Engineering Iowa State University Ames IA USA

ISBN: (纸本)9781509022342

In this paper, reduced-cost design optimization of dual-band antennas is investigated. The primary challenge here is the necessity of independent yet simultaneous handling of the antenna responses at two frequency bands. In order to alleviate this difficulty, a feature-based optimization approach is adopted where the design objectives are formulated in terms of the coordinates of suitably defined characteristic points (also referred to as response features) of the antenna reflection response. Owing to only slightly nonlinear dependence of the feature points on the structure geometry parameters, antenna optimization can be realized at low computational cost compared to conventional algorithms. Our approach is demonstrated using a dual-band patch antenna with the optimum design obtained in just a few dozen of EM simulations of the structure.

关键词： Antenna design dual-band antennas computer-aided design surrogate modeling feature-based optimization dual band antennas antenna design Computer-Aided Design Optimal design Frequency bands design target

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Fast simulation-driven feature-based design optimization of compact dual-band microstrip branch-line coupler

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2016年第1期26卷 13-20页

作者： Koziel, Slawomir Bekasiewicz, Adrian Reykjavik Univ Sch Sci & Engn Engn Optimizat & Modeling Ctr IS-101 Reykjavik Iceland

Design of miniaturized microwave components is a challenging task. On one hand, due to considerable electromagnetic (EM) cross-couplings in highly compressed layouts full-wave EM analysis is necessary for accurate evaluation of the structure performance. Conversely, high-fidelity EM simulation is computationally expensive so that automated determination of the structure dimensions may be prohibitive when using conventional numerical optimization routines. In this article, computationally efficient simulation-driven design of a miniaturized dual-band microstrip branch-line coupler is presented. The optimization methodology relies on suitably extracted features of a highly nonlinear response of the coupler structure under design. The design objectives are formulated in terms of the feature point locations, and the optimization is carried out iteratively with the linear model of the features utilized as a fast predictor. The entire process is embedded in the trust-region framework as convergence safeguard. Owing to only slightly nonlinear dependence of the features on the geometry parameters of the circuit at hand, the optimized design satisfying prescribed performance requirements is obtained at the low computational cost of only 24 high-fidelity EM simulations of the structure. Experimental validation of the fabricated coupler prototype is also provided. (c) 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:13-20, 2016.

关键词： simulation-driven design miniaturized microwave circuits microstrip couplers dual-band couplers feature-based optimization surrogate modeling

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Reliable EM-Driven Design optimization of Miniaturized Rat-Race Couplers

Reliable EM-Driven Design Optimization of Miniaturized Rat-R...

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IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and optimization (NEMO)

作者： Koziel, Slawomir Kurgan, Piotr Reykjavik Univ Engn Optimizat & Modeling Ctr IS-101 Reykjavik Iceland Gdansk Univ Technol Fac Elect Telecommun & Informat PL-80233 Gdansk Poland

ISBN: (纸本)9781538652046

The paper addresses the problem of simulation-driven design of compact microwave couplers. The considered class of structures feature small-size layouts due to so-called compact microstrip resonant cells (CMRCs) incorporated as replacements for conventional transmission lines (TLs). CMRCs exhibit a slow-wave effect, which enables physical shortening of longitudinal circuit dimensions while retaining (within a certain frequency range) approximate electrical or wave parameters. The primary challenge in design of CMRC-based devices is proper adjustment of independent variables. Due to typically intricate CMRC geometries described by a large number of wide-ranged parameters (as compared to ordinary TLs), finding a reasonable starting point for subsequent design optimization poses considerable difficulties. Here, a novel algorithm for reliable CMRC optimization is proposed, which utilizes a combination of pattern search procedures, response features, and variable-fidelity EM simulations. As demonstrated through comprehensive case studies, the algorithm is capable of converging to a good solution regardless of the initial design. Furthermore, the CMRC optimizer is embedded in the design framework, which permits determining a minimum-size coupler with electrical performance that still satisfies design requirements imposed on the structure.

关键词： Compact structures EM optimization EM-driven design feature-based optimization pattern search rat-race couplers variable-fidelity EM models

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Low-cost multiband compact branch-line coupler design using response features and automated EM model fidelity adjustment

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2018年第4期28卷

作者： Koziel, Slawomir Bekasiewicz, Adrian Reykjavik Univ Sch Sci & Engn Engn Optimizat & Modeling Ctr Reykjavik Iceland Gdansk Univ Technol Fac Elect Telecommun & Informat Gdansk Poland

Design closure of compact microwave components is a challenging problem because of significant electromagnetic (EM) cross-couplings in densely arranged layouts. A separate issue is a large number of designable parameters resulting from replacement of conventional transmission line sections by compact microstrip resonant cells. This increases complexity of the design optimization problem and requires employment of expensive high-fidelity EM analysis for reliable performance evaluation of the structure at hand. Consequently, neither conventional numerical optimization algorithms nor interactive approaches (e.g., experience-driven parameters sweeps) are capable of identifying optimum designs in reasonable timeframes. Here, we discuss application of feature-based optimization for fast design optimization of dual- and multiband compact couplers. On one hand, design of such components is difficult because of multiple objectives (achieving equal power split and good matching and port isolation for all frequency bands of interest). On the other hand, because of well-defined shapes of the S-parameter responses for this class of components, feature-based optimization seems to be well suited to control multiple figures of interest as demonstrated in this work. Two-level EM modeling is used for further design cost reduction. More importantly, we develop a procedure for automated determination of the low-fidelity EM model coarseness that allows us to find the fastest possible model that still ensures sufficient correlation with its high-fidelity counterpart, which is critical for robustness of the optimization process. Our approach is illustrated using two dual-band compact couplers. Experimental validation is also provided.

关键词： compact microstrip structures dual-band couplers feature-based optimization model fidelity selection multiband couplers simulation-driven design variable-fidelity simulations

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Expedited simulation-driven design optimization of UWB antennas by means of response features

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2017年第6期27卷

作者： Koziel, Slawomir Bekasiewicz, Adrian Reykjavik Univ Sch Sci & Engn Engn Optimizat & Modeling Ctr Menntavegur 1 IS-101 Reykjavik Iceland

In this work, a method for fast design optimization of broadband antennas is considered. The approach is based on a feature-based optimization (FBO) concept where reflection characteristics of the structure at hand are formulated in terms of suitably defined feature points. Redefinition of the design problem allows for reducing the design optimization cost, because the dependence of feature point coordinates on antenna dimensions is less nonlinear than for the original frequency characteristics (here, S-parameters). This results in faster convergence of the optimization algorithm. The cost of the design process is further reduced using variable-fidelity electromagnetic (EM) simulation models. In case of UWB antennas, the feature points are defined, among others, as the levels of the reflection characteristic at its local in-band maxima, as well as location of the frequency point which corresponds to acceptable reflection around the lower corner frequency within the UWB band. Also, the number of characteristic points depends on antenna topology and its dimensions. Performance of FBO-based design optimization is demonstrated using two examples of planar UWB antennas. Moreover, the computational cost of the approach is compared with conventional optimization driven by a pattern search algorithm. Experimental validation of the numerical results is also provided.

关键词： antenna design design optimization feature-based optimization response features simulation-driven design surrogate modeling UWB antennas

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RAPID DESIGN optimization OF MULTI-BAND ANTENNAS BY MEANS OF RESPONSE featureS

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METROLOGY AND MEASUREMENT SYSTEMS 2017年第2期24卷 337-346页

作者： Koziel, Slawomir Bekasiewicz, Adrian Reykjavik Univ Sch Sci & Engn Menntavegur 1 IS-101 Reykjavik Iceland

This work examines the reduced-cost design optimization of dual-and multi-band antennas. The primary challenge is independent yet simultaneous control of the antenna responses at two or more frequency bands. In order to handle this task, a feature-based optimization approach is adopted where the design objectives are formulated on the basis of the coordinates of so-called characteristic points (or response features) of the antenna response. Due to only slightly nonlinear dependence of the feature points on antenna geometry parameters, optimization can be attained at a low computational cost. Our approach is demonstrated using two antenna structures with the optimum designs obtained in just a few dozen of EM simulations of the respective structure.

关键词： antenna design antenna measurements computer-aided design surrogate modelling feature-based optimization

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Low-Cost Multi-Objective optimization of Antennas Using Pareto Front Exploration and Response features

Low-Cost Multi-Objective Optimization of Antennas Using Pare...

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IEEE-Antennas-and-Propagation-Society International Symposium

作者： Koziel, Slawomir Bekasiewicz, Adrian Reykjavik Univ Sch Sci & Engn Reykjavik Iceland Gdansk Univ Technol Fac Elect Telecommun & Informat Gdansk Poland

ISBN: (纸本)9781509028863

In the paper, a procedure for low-cost multiobjective optimization of antenna structures is presented. Our approach is based on exploration of the Pareto front representing the best possible trade-offs between conflicting objectives, here, the structure size and its electrical performance. Starting from the design representing the best in-band reflection level, subsequent Pareto-optimal designs are identified through local constrained optimization aimed at reducing the structure size while maintaining the prescribed thresholds concerning the reflection response. For the sake of computational efficiency, variable-fidelity EM simulation models and feature-based optimization algorithm is utilized. The proposed methodology is demonstrated using a compact UWB monopole antenna.

关键词： Antenna design multi-objective optimization surrogate modeling feature-based optimization

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Fast Design optimization of UWB Antennas Using Response features 21

Fast Design Optimization of UWB Antennas Using Response Feat...

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21st International Conference on Microwave, Radar and Wireless Communications (MIKON)

作者： Koziel, Slawomir Bekasiewicz, Adrian Reykjavik Univ Sch Sci & Engn Reykjavik Iceland

ISBN: (纸本)9781509022144

A computationally efficient technique for design optimization of UWB antennas has been presented. Our approach adopts feature-based optimization (FBO) concept where the computational speedup is achieved by reformulating the design specifications in terms of suitably defined response features. Because the dependence of the feature point coordinates on geometry parameters of the antenna is much less nonlinear than for the original characteristics (e.g., S-parameters versus frequency), the optimization algorithm converges faster. Moreover, variable-fidelity electromagnetic (EM) simulation models are utilized to further reduce the optimization cost. In case of UWB antennas, the feature points are defined, among others, as local maxima of the reflection characteristic within the UWB frequency band, as well as the frequency location of the point corresponding to acceptable reflection level in the vicinity of the lower edge of the band (3.1 GHz). The issue related to possible change of the number of the feature points during the optimization run has been also addressed. Operation and performance of our technique is demonstrated using an example monopole antenna. It is also compared to conventional optimization using pattern search.

关键词： Antenna design UWB antennas design optimization simulation-driven design response features feature-based optimization surrogate modeling

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