Stanislav Ogurtsov - Academia.edu (original) (raw)

Uploads

Papers by Stanislav Ogurtsov

2015 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2015

Springer Proceedings in Mathematics & Statistics, 2014

Design optimization of dielectric resonator antennas (DRAs) is a challenging task that normally i... more Design optimization of dielectric resonator antennas (DRAs) is a challenging task that normally involves electromagnetic (EM) simulation. Automated simulation-based DRA design realized as an optimization problem with a discrete EM solver directly embedded into the optimization algorithm is often very time consuming due to computational demands of discrete high-fidelity simulations. Here, we demonstrate a computationally efficient optimization approach to DRA

Ieee Transactions on Antennas and Propagation, Dec 1, 2007

We describe a rigorous analysis of unconditional stability for the alternating-direction-implicit... more We describe a rigorous analysis of unconditional stability for the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) and Crank-Nicholson split step (CNSS-FDTD) schemes avoiding use of the von Neumann spectral criterion. The proof is performed in the spectral domain, and uses skew-Hermitivity of matrix terms in the ADI and CNSS total amplification matrices. A bound for the total ADI amplification matrix is provided. While the CN and CNSS-FDTD amplification matrices are unitary, the bound on the ADI-FDTD depends on the Courant number. Importantly, we have found that the ADI-FDTD amplification matrix is not normal, i.e., the unit spectral radius alone cannot be used to prove the ADI-FDTD unconditional stability. The paper also shows that the ADI-FDTD and CNSS-FDTD schemes share the same dispersion equation by a similarity of their total amplification matrices, and the two schemes have identical numerical dispersion in the frame of plane waves.

2013 7th European Conference on Antennas and Propagation, 2013

ABSTRACT A simple and low-cost methodology for modeling of wideband antennas is discussed. Our ap... more ABSTRACT A simple and low-cost methodology for modeling of wideband antennas is discussed. Our approach exploits variable-fidelity electromagnetic (EM) simulations, kriging and space mapping (SM). The initial kriging surrogate created by interpolating densely sampled low-fidelity EM simulations of the antenna structure of interest is further enhanced using SM and a limited amount of high-fidelity simulations. The resulting model is fast, of reasonable accuracy, and it is created at a computational cost that is substantially lower than that of conventional response surface approximation modeling based on direct interpolation of high-fidelity simulation data. Our technique is demonstrated using two examples: a broadband CPW-fed slot antenna and an ultra-wideband monopole antenna.

2011 41st European Microwave Conference, 2011

ABSTRACT A computationally efficient algorithm for simulation-driven design optimization of micro... more ABSTRACT A computationally efficient algorithm for simulation-driven design optimization of microwave structures is proposed. Our approach exploits variable-fidelity electromagnetic models of the structure under consideration. The low-fidelity model is optimized using a response surface approximation technique. The high-fidelity model is refined by space mapping with polynomial interpolation of the low-fidelity model data used as an underlying coarse model. Our algorithm is carefully developed to minimize the number off evaluations of both the low- and high-fidelity model in the optimization process. The operation and efficiency of the approach is demonstrated through design of a microstrip filter and an ultrawideband monopole antenna. A comparison with other design approaches, including the direct high-fidelity model optimization, is also presented.

2013 7th European Conference on Antennas and Propagation, 2013

ABSTRACT A methodology for computationally efficient simulation-driven design of microstrip anten... more ABSTRACT A methodology for computationally efficient simulation-driven design of microstrip antenna subarrays is presented. Our approach takes into account the effect of the feed (e.g., a corporate network) on the subarray side lobe level and allows adjusting both radiation and reflection responses of the structure under design within a single automated process. This process is realized as surrogate-based optimization that produces designs meeting requirements imposed on both radiation and reflection at the cost of just a few simulations of the high-fidelity model of the structure of interest. Selected optimal designs of microstrip subarrays operating at 10 GHz have been manufactured and validated by measuring their radiation patterns and reflection coefficients.

Http Dx Doi Org 10 1080 0305215x 2011 620100, Jul 12, 2012

An improved variable-fidelity optimization algorithm for the simulation-driven design of microwav... more An improved variable-fidelity optimization algorithm for the simulation-driven design of microwave structures is presented. It exploits a set of electromagnetic-based models of increasing discretization density. These models are sequentially optimized with the optimum of the ‘coarser’ model being the initial design for the ‘finer’ one. The found optimum is further refined using a response surface approximation model constructed from the coarse-discretization simulation data. In this work, the computational efficiency of the variable-fidelity algorithm is enhanced by employing a novel algorithm for optimizing the coarse-discretization models. This allows reduction of the overall design time by up to 50% compared to the previous version. The presented technique is particularly suitable for problems where simulation-driven design is the only option, for example, ultra wideband and dielectric resonator antennas. Operation of the presented approach is demonstrated using two examples of antennas and a microstrip filter. In all cases, the optimal design is obtained at a low computational cost corresponding to a few high-fidelity simulations of the structure.

2012 7th European Microwave Integrated Circuit Conference, 2012

ABSTRACT We introduce a robust and reliable algorithm for computationally efficient design optimi... more ABSTRACT We introduce a robust and reliable algorithm for computationally efficient design optimization of microwave structures evaluated with electromagnetic (EM) simulations. Our approach utilizes low-fidelity model constructed from coarse-discretization EM simulation of the structure of interest as well as cheap derivative information obtained through adjoint sensitivity. Adjoint sensitivity which is exploited threefold: (i) to reduce the misalignment between the low- and high-fidelity models through input space mapping, (ii) to construct a first-order consistent surrogate model through manifold mapping, (iii) to optimize the surrogate through trust-region based algorithm. The comprehensive use of adjoint sensitivity results in a very low design cost and excellent convergence capability of the proposed algorithm. Efficiency of our approach is demonstrated through the design of an ultra-wideband antenna and a microstrip bandpass filter.

IEEE Antennas and Wireless Propagation Letters, 2015

A design of an ultrawideband (UWB) antenna with an integrated balun is presented. A fully planar ... more A design of an ultrawideband (UWB) antenna with an integrated balun is presented. A fully planar balun configuration interfacing the microstrip input of the structure to the coplanar stripline (CPS) input of the dipole antenna is introduced. The electromagnetic (EM) model of the structure of interest includes the dipole, the balun, and the microstrip input to account for coupling and radiation effects over the UWB band. The EM model is then adjusted for low reflection over the UWB band by means of fast simulation-driven surrogate-based optimization. This approach allows us to obtain the final design at low computational costs and at a high-fidelity level of structure description. Measurements of the manufactured optimal design validate the use of the balun as well as the design approach.

2014 Loughborough Antennas and Propagation Conference (LAPC), 2014

2013 International Conference on Electromagnetics in Advanced Applications, Sep 1, 2013

IET Microwaves, Antennas & Propagation, 2014

ABSTRACT A new development of the shape-preserving response prediction (SPRP) technique for micro... more ABSTRACT A new development of the shape-preserving response prediction (SPRP) technique for microwave design optimisation is presented here. The original SPRP method is enhanced by employing low-cost derivative information obtained through adjoint sensitivities. The authors propose using operator notation to simplify the SPRP surrogate description. The enhancement through sensitivity data is twofold: to ensure first-order consistency between the SPRP surrogate and the high-fidelity electromagnetic (EM) model under optimisation and to speed up the surrogate optimisation process. Fast surrogate optimisation allows us to use coarse-discretisation EM simulations as an underlying low-fidelity model and, therefore, efficiently apply SPRP to cases where reliable circuit models are not available (e.g. design of antenna structures). The proposed approach is demonstrated using a dielectric resonator filter and an ultra-wideband monopole antenna. Comparison with three benchmark techniques, including the original SPRP methods, space mapping with sensitivity and direct optimisation of the high-fidelity model, is also provided.

Advances in Intelligent Systems and Computing, 2014

Advances in Intelligent Systems and Computing, 2014

Advances in Intelligent Systems and Computing, 2014

Simulation-Driven Design Optimization and Modeling for Microwave Engineering, 2013

A simulation-driven optimization framework for computationally efficient design of ultrawideband ... more A simulation-driven optimization framework for computationally efficient design of ultrawideband (UWB) antennas is presented. Our approach exploits coarselydiscretized electromagnetic (EM) simulations as a low-fidelity model of the antenna under consideration. This low-fidelity model is used as a prediction tool to find an approximate optimum design. The discrepancy between the low-and the highfidelity models is accounted for by appropriate modifications of the design requirements. Efficiency of the presented technique is demonstrated through the design of an UWB monopole and an antipodal Vivaldi antenna.

Progress In Electromagnetics Research B

Application of multi-dimensional Cauchy approximation and coarse-discretization electromagnetic (... more Application of multi-dimensional Cauchy approximation and coarse-discretization electromagnetic (EM) models to surrogatebased optimization of microwave structures is discussed. Space mapping is used as an optimization engine with the surrogate model constructed as a Cauchy approximation of the coarsely discretized device EM model. The proposed approach allows us to perform computationally efficient optimization of microwave structures without using circuit-equivalent coarse models traditionally exploited by space mapping algorithms. We demonstrate our technique through design of a range of microwave devices, including filters, antennas, and transitions. Comprehensive numerical verification of the proposed methodology is carried out with satisfactory designs obtained -for all considered devices -at a computational cost corresponding to a few full-wave simulations.

2015 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2015

Springer Proceedings in Mathematics & Statistics, 2014

Design optimization of dielectric resonator antennas (DRAs) is a challenging task that normally i... more Design optimization of dielectric resonator antennas (DRAs) is a challenging task that normally involves electromagnetic (EM) simulation. Automated simulation-based DRA design realized as an optimization problem with a discrete EM solver directly embedded into the optimization algorithm is often very time consuming due to computational demands of discrete high-fidelity simulations. Here, we demonstrate a computationally efficient optimization approach to DRA

Ieee Transactions on Antennas and Propagation, Dec 1, 2007

We describe a rigorous analysis of unconditional stability for the alternating-direction-implicit... more We describe a rigorous analysis of unconditional stability for the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) and Crank-Nicholson split step (CNSS-FDTD) schemes avoiding use of the von Neumann spectral criterion. The proof is performed in the spectral domain, and uses skew-Hermitivity of matrix terms in the ADI and CNSS total amplification matrices. A bound for the total ADI amplification matrix is provided. While the CN and CNSS-FDTD amplification matrices are unitary, the bound on the ADI-FDTD depends on the Courant number. Importantly, we have found that the ADI-FDTD amplification matrix is not normal, i.e., the unit spectral radius alone cannot be used to prove the ADI-FDTD unconditional stability. The paper also shows that the ADI-FDTD and CNSS-FDTD schemes share the same dispersion equation by a similarity of their total amplification matrices, and the two schemes have identical numerical dispersion in the frame of plane waves.

2013 7th European Conference on Antennas and Propagation, 2013

ABSTRACT A simple and low-cost methodology for modeling of wideband antennas is discussed. Our ap... more ABSTRACT A simple and low-cost methodology for modeling of wideband antennas is discussed. Our approach exploits variable-fidelity electromagnetic (EM) simulations, kriging and space mapping (SM). The initial kriging surrogate created by interpolating densely sampled low-fidelity EM simulations of the antenna structure of interest is further enhanced using SM and a limited amount of high-fidelity simulations. The resulting model is fast, of reasonable accuracy, and it is created at a computational cost that is substantially lower than that of conventional response surface approximation modeling based on direct interpolation of high-fidelity simulation data. Our technique is demonstrated using two examples: a broadband CPW-fed slot antenna and an ultra-wideband monopole antenna.

2011 41st European Microwave Conference, 2011

ABSTRACT A computationally efficient algorithm for simulation-driven design optimization of micro... more ABSTRACT A computationally efficient algorithm for simulation-driven design optimization of microwave structures is proposed. Our approach exploits variable-fidelity electromagnetic models of the structure under consideration. The low-fidelity model is optimized using a response surface approximation technique. The high-fidelity model is refined by space mapping with polynomial interpolation of the low-fidelity model data used as an underlying coarse model. Our algorithm is carefully developed to minimize the number off evaluations of both the low- and high-fidelity model in the optimization process. The operation and efficiency of the approach is demonstrated through design of a microstrip filter and an ultrawideband monopole antenna. A comparison with other design approaches, including the direct high-fidelity model optimization, is also presented.

2013 7th European Conference on Antennas and Propagation, 2013

ABSTRACT A methodology for computationally efficient simulation-driven design of microstrip anten... more ABSTRACT A methodology for computationally efficient simulation-driven design of microstrip antenna subarrays is presented. Our approach takes into account the effect of the feed (e.g., a corporate network) on the subarray side lobe level and allows adjusting both radiation and reflection responses of the structure under design within a single automated process. This process is realized as surrogate-based optimization that produces designs meeting requirements imposed on both radiation and reflection at the cost of just a few simulations of the high-fidelity model of the structure of interest. Selected optimal designs of microstrip subarrays operating at 10 GHz have been manufactured and validated by measuring their radiation patterns and reflection coefficients.

Http Dx Doi Org 10 1080 0305215x 2011 620100, Jul 12, 2012

An improved variable-fidelity optimization algorithm for the simulation-driven design of microwav... more An improved variable-fidelity optimization algorithm for the simulation-driven design of microwave structures is presented. It exploits a set of electromagnetic-based models of increasing discretization density. These models are sequentially optimized with the optimum of the ‘coarser’ model being the initial design for the ‘finer’ one. The found optimum is further refined using a response surface approximation model constructed from the coarse-discretization simulation data. In this work, the computational efficiency of the variable-fidelity algorithm is enhanced by employing a novel algorithm for optimizing the coarse-discretization models. This allows reduction of the overall design time by up to 50% compared to the previous version. The presented technique is particularly suitable for problems where simulation-driven design is the only option, for example, ultra wideband and dielectric resonator antennas. Operation of the presented approach is demonstrated using two examples of antennas and a microstrip filter. In all cases, the optimal design is obtained at a low computational cost corresponding to a few high-fidelity simulations of the structure.

2012 7th European Microwave Integrated Circuit Conference, 2012

ABSTRACT We introduce a robust and reliable algorithm for computationally efficient design optimi... more ABSTRACT We introduce a robust and reliable algorithm for computationally efficient design optimization of microwave structures evaluated with electromagnetic (EM) simulations. Our approach utilizes low-fidelity model constructed from coarse-discretization EM simulation of the structure of interest as well as cheap derivative information obtained through adjoint sensitivity. Adjoint sensitivity which is exploited threefold: (i) to reduce the misalignment between the low- and high-fidelity models through input space mapping, (ii) to construct a first-order consistent surrogate model through manifold mapping, (iii) to optimize the surrogate through trust-region based algorithm. The comprehensive use of adjoint sensitivity results in a very low design cost and excellent convergence capability of the proposed algorithm. Efficiency of our approach is demonstrated through the design of an ultra-wideband antenna and a microstrip bandpass filter.

IEEE Antennas and Wireless Propagation Letters, 2015

A design of an ultrawideband (UWB) antenna with an integrated balun is presented. A fully planar ... more A design of an ultrawideband (UWB) antenna with an integrated balun is presented. A fully planar balun configuration interfacing the microstrip input of the structure to the coplanar stripline (CPS) input of the dipole antenna is introduced. The electromagnetic (EM) model of the structure of interest includes the dipole, the balun, and the microstrip input to account for coupling and radiation effects over the UWB band. The EM model is then adjusted for low reflection over the UWB band by means of fast simulation-driven surrogate-based optimization. This approach allows us to obtain the final design at low computational costs and at a high-fidelity level of structure description. Measurements of the manufactured optimal design validate the use of the balun as well as the design approach.

2014 Loughborough Antennas and Propagation Conference (LAPC), 2014

2013 International Conference on Electromagnetics in Advanced Applications, Sep 1, 2013

IET Microwaves, Antennas & Propagation, 2014

ABSTRACT A new development of the shape-preserving response prediction (SPRP) technique for micro... more ABSTRACT A new development of the shape-preserving response prediction (SPRP) technique for microwave design optimisation is presented here. The original SPRP method is enhanced by employing low-cost derivative information obtained through adjoint sensitivities. The authors propose using operator notation to simplify the SPRP surrogate description. The enhancement through sensitivity data is twofold: to ensure first-order consistency between the SPRP surrogate and the high-fidelity electromagnetic (EM) model under optimisation and to speed up the surrogate optimisation process. Fast surrogate optimisation allows us to use coarse-discretisation EM simulations as an underlying low-fidelity model and, therefore, efficiently apply SPRP to cases where reliable circuit models are not available (e.g. design of antenna structures). The proposed approach is demonstrated using a dielectric resonator filter and an ultra-wideband monopole antenna. Comparison with three benchmark techniques, including the original SPRP methods, space mapping with sensitivity and direct optimisation of the high-fidelity model, is also provided.

Advances in Intelligent Systems and Computing, 2014

Advances in Intelligent Systems and Computing, 2014

Advances in Intelligent Systems and Computing, 2014

Simulation-Driven Design Optimization and Modeling for Microwave Engineering, 2013

A simulation-driven optimization framework for computationally efficient design of ultrawideband ... more A simulation-driven optimization framework for computationally efficient design of ultrawideband (UWB) antennas is presented. Our approach exploits coarselydiscretized electromagnetic (EM) simulations as a low-fidelity model of the antenna under consideration. This low-fidelity model is used as a prediction tool to find an approximate optimum design. The discrepancy between the low-and the highfidelity models is accounted for by appropriate modifications of the design requirements. Efficiency of the presented technique is demonstrated through the design of an UWB monopole and an antipodal Vivaldi antenna.

Progress In Electromagnetics Research B

Application of multi-dimensional Cauchy approximation and coarse-discretization electromagnetic (... more Application of multi-dimensional Cauchy approximation and coarse-discretization electromagnetic (EM) models to surrogatebased optimization of microwave structures is discussed. Space mapping is used as an optimization engine with the surrogate model constructed as a Cauchy approximation of the coarsely discretized device EM model. The proposed approach allows us to perform computationally efficient optimization of microwave structures without using circuit-equivalent coarse models traditionally exploited by space mapping algorithms. We demonstrate our technique through design of a range of microwave devices, including filters, antennas, and transitions. Comprehensive numerical verification of the proposed methodology is carried out with satisfactory designs obtained -for all considered devices -at a computational cost corresponding to a few full-wave simulations.