A nearresonance decoupling approach (NRDA) for scattering solution of nearresonant structures

The generalized network formulation is applied in combination with the method of moments to calculate the electromagnetic scattering from conducting objects containing nearresonant openended cavities. The presence of the cavity increases the iteration number in conjugate gradient iterations due to the nearresonant modes and the multiple wave bounces inside the cavity. The equivalence principle is used to separate the cavity region from the rest of the object, allowing an independent solution of the cavity problem by a direct inversion algorithm using a connection scheme [11]. The solution of the cavity is then represented by a generalized admittance matrix. Numerical results for twodimensional (2D) composite targets show that the iteration number can be reduced significantly for objects containing long cavities. This algorithm can also be applied to threedimensional problems which will be reported in the future.