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We present a level set method for numerical shape optimization of electromagnetic systems. The level set method does not only lead to efficient computational schemes, but also is able to handle topological changes such as merging, splitting and even disappearing of connected components. The velocity field on boundaries is obtained by a shape derivative of continuum sensitivity analysis using the material derivative concept and an adjoint variable technique. Two numerical results of dielectric optimization between electrodes showed that the level set method is feasible and effective in solving shape optimization problems of electromagnetic systems. Index Terms--Continuum sensitivity, finite-element analysis (FEA), level set method, shape optimization.

This paper shows applied sensitivity analysis for easier design and practical application of a planar half-wavelength low-pass filter (LPF) using defected ground structure (DGS). Typically, it is difficult to deploy planar half-wavelength low-pass filters when high power durability is required because of the very narrow line-widths of high impedance transmission line. Here, we propose a new configuration for the high impedance microstrip line using DGS structure to allow broader line width and high power handling capability. The sensitivity of the scattering parameters was calculated using the self-adjoint sensitivity formula in order to determine the proposed filter's dimension. The paper also highlights the validity of the proposed LPF optimization with its measured performance. Index Terms--Defected ground structure (DGS), low-pass filter (LPF), self-adjoint method, sensitivity analysis.

A topology optimization technique is applied to the design of dielectric-loaded waveguide filters. Dielectric material distribution inside the waveguide is optimized to achieve desired frequency response. A gradient-based optimizer is used for topology optimization, along with adjoint variable method to calculate sensitivity. The results of numerical examples show feasibility of the proposed method. Index Terms--Dielectric resonator, sensitivity analysis, topology optimization, waveguide filter.

Numerical simulations of body-of-revolution geometries for scattering and radiation problems are presented. The formulation consists of a finite element-boundary integral (FE-BI) method which is based on a finite element method that uses higher order nodal-based scalar basis functions for the azimuthal field component and higher order edge-based vector basis functions for the transverse field. This formulation, when combined with a symmetric FE-BI hybridization scheme, yields a final system of equations that is more accurate than earlier first-order formulations. Numerical examples are given to demonstrate the accuracy and capabilities of the higher order solution. Index Terms--Body of revolution (BOR), electromagnetic radiation, electromagnetic scattering, finite element method (FEM), method of moments (MoM), radar cross section (RCS).

The rotor winding shape of HTS (High Temperature Superconducting) motor is designed to maximum flux-linkage of stator winging with a given amount of superconductor volume. With the help of three step design procedure of shape design and sizing design, the final optimal rotor winding for easy industrial manufacturing was obtained.

The advantages and shortcomings of shape optimization and topology optimization method are compared for High Temperature Superconducting (HTS) solenoid design. Design results indicate that it is best to use topology optimization method for basic layout design and use shape optimization method for fine-tuning of the basic layout.

In this paper, a new node-based material distribution scheme is proposed for topology optimization of electromagnetic devices. Electromagnetic properties of material such as permeability and current density are given on the nodes of finite-element mesh, and within each element, they are interpolated using the nodal values. The proposed method can be used to alleviate the coarse layout of final device, which occurs frequently in conventional topology optimization. Numerical examples are given to show the effectiveness of the proposed method. Index Terms--Magnetic resonance imaging (MRI) design, node-based material property distribution, superconducting coil distribution, topology optimization (TO).

This paper presents a new shape design sensitivity analysis for the general superconducting system. The proposed method takes into account the nonlinear dependence of the critical current on the maximum magnetic flux density in the sensitivity calculation. The [J.sub.c]-[B.sub.m] curve of the superconducting material is interpolated from the measurement data. The design of a magnetic resonance imaging superconducting solenoid is given as a numerical example. Index Terms--Critical current, design sensitivity, shape optimization, superconducting system.

A new design approach is described which uses the topology optimization method in a superconducting system.

In this paper, topology optimization approach is used for the design of the electrostatic actuator that can be manufactured by microelectromechanical system (MEMS) technology. The design goal is to obtain constant maximum torque by properly distributing dielectric material in the design space of rotor. The objective function is defined for the difference of the system energy to be maximized with respect to the rotation of the rotor. The detailed design with unique shape of rotor pole is achieved. Also, the effect of mesh size and initial conditions on final rotor shape is discussed. Index Terms--Density method, design sensitivity, electrostatic actuator, topology optimization.

This paper presents a physical and geometrical design sensitivity algorithm for the optimal temperature control of the induction heating devices. The exciting coil positions and the source current density are taken as design parameters together and renewed simultaneously in every iterative step by using the Levenberg-Marquardt method, which can achieve better results. This method can also give a faster and more stable convergence of the objective function than conventional steepest descent method. The proposed algorithm is applied to a numerical example and verified. Index terms - Induction heating, design sensitivity, physical and geometrical parameter, Levenberg-Marquardt method

This paper presents a new topology optimization technique for electromagnetic problems. Mutual energy terms are defined in the electromagnetic system, and the objective function that represents the design objective is expressed in terms of mutual energy. The design sensitivity is calculated from the first variation of mutual energy and the density method is used to optimize the material property distribution in the design region using the obtained sensitivity. The proposed algorithm is applied to a numerical example of transformer core topology optimization and verified. Index Terms--Density method, design sensitivity, mutual energy, topology optimization

A new and faster sensitivity calculation algorithm for the source current distribution problem is proposed. The reciprocity theorem is used to reduce the calculation time. The proposed method is efficient when there are a large number of design variables. Index Terms--Current distribution problem, design sensitivity, magnetic resonance imaging, reciprocity theorem.