Shape optimization of a dielectric resonator for improving its unloaded quality factor

A novel approach for shape optimization of dielectric resonators is presented with an objective of improving their unloaded quality factor. Shape (level-set) and topology (topology gradient) optimization methods coupled with finite element method are utilized together, which as a result, relaxes the traditional trade-off made between the spurious-free band (isolation) and the high unloaded quality factor of the resonators. The defined cost function is minimized by the proposed iterative coupling between the level-set method and the topology gradient method. The optimized resonator, which improves the unloaded quality factor of about 65% compared with the reference, is then approximated for fabrication. The reference, optimized, and approximated resonators are fabricated and measured. Results from the simulated and the fabricated resonators validate the optimization approach presented in this work. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. © 2011 Wiley Periodicals, Inc.

[1]  Jan Sokolowski,et al.  On the Topological Derivative in Shape Optimization , 1999 .

[2]  Wansoo Nah,et al.  Comparison of shape and topology optimization methods for HTS solenoid design , 2004 .

[3]  Jin-kyu Byun,et al.  Topology optimization of electrical devices using material energy and sensitivity , 1999, IEEE International Magnetics Conference.

[4]  Il Han Park,et al.  A Level Set Method for Shape Optimization of Electromagnetic Systems , 2009 .

[5]  Jin-Kyu Byun,et al.  Design of Dielectric Waveguide Filters Using Topology Optimization Technique , 2006, IEEE Transactions on Magnetics.

[6]  Dominique Baillargeat,et al.  Shape optimized design of microwave dielectric resonators by level-set and topology gradient methods , 2010 .

[7]  J. Sethian,et al.  Fronts propagating with curvature-dependent speed: algorithms based on Hamilton-Jacobi formulations , 1988 .

[8]  S. Osher,et al.  Level Set Methods for Optimization Problems Involving Geometry and Constraints I. Frequencies of a T , 2001 .

[9]  Kecheng Liu,et al.  Shape recovery algorithms using level sets in 2-D/3-D medical imagery: a state-of-the-art review , 2002, IEEE Transactions on Information Technology in Biomedicine.

[10]  S. J. Fiedziuszko,et al.  Dielectric resonators raise your high-Q , 2001 .

[11]  M. El-Shenawee,et al.  Shape Reconstruction Using the Level Set Method for Microwave Applications , 2008, IEEE Antennas and Wireless Propagation Letters.

[12]  G. Allaire,et al.  A level-set method for shape optimization , 2002 .

[13]  J. Sethian,et al.  Structural Boundary Design via Level Set and Immersed Interface Methods , 2000 .

[14]  Hao Ling,et al.  Design of broadband and dual-band microstrip antennas on a high-dielectric substrate using a genetic algorithm , 2003 .

[15]  Tsuyoshi Nomura,et al.  Structural topology optimization for the design of broadband dielectric resonator antennas using the finite difference time domain technique , 2007 .