$S$-Parameter Sensitivities for Electromagnetic Optimization Based on Volume Field Solutions

Nikolova, Natalia K.; Zhu, Xiaying; Song, Yunpeng; Hasib, A.; Bakrare, M.H.

doi:10.1109/tmtt.2009.2020828

Cited by 28 publications

(6 citation statements)

References 18 publications

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“…The adjoint field Ê is not uniquely defined until the boundary conditions complementing (13) are set. They are usually chosen to be the same as those of the original problem [48,49]. This offers several advantages including self-adjoint sensitivity formulations.…”

Section: Adjoint-variable Methods In Electromagneticsmentioning

confidence: 99%

Near-field detection at microwave frequencies based on self-adjoint response sensitivity analysis

2010

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A new detection method is proposed for the localization of electrically small scatterers in a known background medium. The method requires the knowledge of the electric field distribution inside the known background medium where no scatterers are present. It is based on a self-adjoint response sensitivity computation which can be performed in real time. Using the E-field distribution in the background medium, it provides three-dimensional maps of the Fréchet derivative within the imaged volume. The peaks and dips in these maps identify the locations where the permittivity and conductivity of the measured medium differ from those in the background medium. The background medium can be heterogeneous. In a homogeneous-medium example, the performance of the detection algorithm is studied in terms of the number of transmission/reception points, the dielectric contrast of the scatterer compared to the background medium, and the size of the scatterer. Its resolution is also addressed. The detection of a small scatterer in a heterogeneous background is demonstrated.

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Section: Adjoint-variable Methods In Electromagneticsmentioning

confidence: 99%

Near-field detection at microwave frequencies based on self-adjoint response sensitivity analysis

2010

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“…Nikolova et al [24] spurred EM optimization with their EM theory of network-parameter self-adjoint sensitivity analysis. EM-based adjoint methods have been extended to both the frequency and time domains, e.g., [25].…”

Section: Towards Em-based Design Optimizationmentioning

confidence: 99%

Retrospective on microwave CAD and optimization technology

Cheng

2012

2012 IEEE/MTT-S International Microwave Symposium Digest

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Some 45 years of microwave CAD technology includes least pth and minimax objectives, direct search and gradient methods, and adjoint sensitivity techniques. The 1980's saw the acceptance of commercial CAD software and yielddriven methodologies. The 1990's introduced space mapping for design and modeling based on full-wave electromagnetic simulations. We address these and further advances in the context of today's stringent requirements for CAD solutions.Index Terms-microwave CAD, sensitivity analysis, space mapping, design optimization, electromagnetic simulation. I. MICROWAVE CIRCUIT CADGetsinger's 1969 special issue on "Computer-oriented Microwave Practices" brought CAD technology and optimization techniques to the attention of microwave designers. This and the follow-up 1974 special issue ensured the recognition of CAD by the microwave community.Director and Rohrer [1] introduced the adjoint approach to sensitivity evaluation, which exploits a simple relation between the original circuit and an auxiliary or "adjoint" circuit (in 1973, Branin suggested the transpose of the nodal admittance matrix) and element level sensitivity expressions. As a result, the computational effort to evaluate the first-order derivatives of any response with respect to all design parameters corresponds essentially to two circuit analyses. For example, the exact sensitivity expression for an inductor iswhere L is the inductance, ω is frequency, and I and Î are currents in the original and adjoint elements, respectively. Following a series of papers, Bandler and Seviora [ 2 ] extended the adjoint concept to first-and second-order sensitivities of networks with respect to network parameters in terms of wave variables. First-order sensitivity formulas are available for a variety of elements, including lumped and uniformly distributed elements, active and passive elements, and reciprocal and nonreciprocal elements. Parameters include electrical quantities, geometrical dimensions, and frequency.A 1972 paper [ 3 ] proposed least pth objectives with extremely large values of p. It demonstrated near minimax results using gradient optimization. Bandler [4] reviewed least pth and minimax objectives, gradient and direct search methods, as well as adjoint circuit sensitivity techniques.

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“…This achievement is no less than a breakthrough, especially bearing in mind that, to our knowledge, adjoint sensitivities have not been implemented yet in microwave circuit-based commercial software. These computations exploit a self-adjoint sensitivity formula (see, e.g., [12]) for the scattering parameters which requires very little computational overhead compared to that of the EM simulation regardless of the number of design variables, or, equivalently, the number of required response derivatives.…”

Section: Introductionmentioning

confidence: 99%

Re-discovering adjoint sensitivities: Toward field-based analysis

Nikolova

Dadash²,

Bakr

et al. 2012

2012 IEEE/MTT-S International Microwave Symposium Digest

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Computing the derivatives of the scattering parameters of microwave devices with respect to shape and material parameters is a problem of significant interest in highfrequency computer-aided design. The pioneering work of Bandler, Monaco, Tiberio and others in the late 1960s and the early 1970s brought about the circuit-based sensitivity analysis of microwave networks. Here, we discuss some of the recent developments in adjoint sensitivities including field-based sensitivities, transient adjoint sensitivities, and adjoint-based neural networks. Two examples illustrate these approaches.

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$S$-Parameter Sensitivities for Electromagnetic Optimization Based on Volume Field Solutions

Cited by 28 publications

References 18 publications

Near-field detection at microwave frequencies based on self-adjoint response sensitivity analysis

Near-field detection at microwave frequencies based on self-adjoint response sensitivity analysis

Retrospective on microwave CAD and optimization technology

Re-discovering adjoint sensitivities: Toward field-based analysis

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