# 루프-스타(Loop-Star) 기저 함수와 전제 조건(Preconditioner)을 이용한 모멘트법의 계산 효율 향상에 대한 연구

• Yeom, Jae-Hyun (Department of Electronic and Electrical Engineering, Pohang University of Science and Technology) ;
• Park, Hyeon-Gyu (Department of Electronic and Electrical Engineering, Pohang University of Science and Technology) ;
• Lee, Hyun-Suck (Department of Electronic and Electrical Engineering, Pohang University of Science and Technology) ;
• Chin, Hui-Cheol (Department of Electronic and Electrical Engineering, Pohang University of Science and Technology) ;
• Kim, Hyo-Tae (Department of Electronic and Electrical Engineering, Pohang University of Science and Technology) ;
• Kim, Kyung-Tae (Department of Electronic and Electrical Engineering, Pohang University of Science and Technology)
• 염재현 (포항공과대학교 전자전기공학과) ;
• 박현규 (포항공과대학교 전자전기공학과) ;
• 이현석 (포항공과대학교 전자전기공학과) ;
• 진희철 (포항공과대학교 전자전기공학과) ;
• 김효태 (포항공과대학교 전자전기공학과) ;
• 김경태 (포항공과대학교 전자전기공학과)
• Accepted : 2011.12.29
• Published : 2012.02.29
• 71 51

#### Abstract

This paper uses loop-star basis functions to overcome the low frequency breakdown problem in method of moments (MoM) based on electric field integral equation(EFIE). In addition, p-Type Multiplicative Schwarz preconditioner (p-MUS) technique is employed to reduce the number of iterations required for the conjugate gradient method(CGM). Low frequency instability with Rao Wilton Glisson(RWG) basis functions in EFIE can be resolved using loop-start basis functions and frequency normalized techniques. However, loop-star basis functions, consisting of irrotational and solenoidal components of RWG basis functions, require a large number of iterations to calculate a solution through iterative methods, such as conjugate gradient method(CGM), due to high condition number. To circumvent this problem, in this paper, the pMUS preconditioner technique is proposed to reduce the number of iterations in CGM. Simulation results show that pMUS preconditioner is much faster than block diagonal preconditioner(BDP) when the sparsity of pMUS is the same as that of BDP.

#### Keywords

Electromagnetic Scattering;Loop-Star Basis Function;Preconditioner Matrix;Incomplete Helmholtz Theorem

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