The system matrices generated by the moment methods are ill-conditioned matrices

which make the iterative methods hardly converge

even accelerated by the existing preconditioning techniques.This paper applies the concept of regularization methods of ill-posed problems

and introduces the so-called regularization matrix as a preconditioner.This preconditioner can shift the eigenvalues of the system matrix directly.And it needs no additional memory to store the preconditioner.Furthermore

this paper proposes to determine the optimized regularization parameter by finding the maximum value of the second derivative of the L-curve of the regularized matrix.Numerical experiments show that the proposed method can converge relatively fast for some matrix equation generated by the electric field integral equation (EFIE) or the magnetic field integral equation (MFIE) solved with the higher order moment method

while iterative methods with the existing preconditioners may converge slowly.