Effect of multipoles in resolution with Linear Sampling Method

Linear Sampling Method (LSM) is a reliable, simple and effective method for finding the shape and location of the unknown targets. It achieves the task by focusing the scattered fields from the objects to a monopole radiation. But, the resolution capabilities of LSM are ineffective when the scatterers are closely placed compare to the wavelength of microwave fields. In this paper we show that, this problem is overcome by applying the multipole based Linear Sampling Method (MSLM) where the scattered fields are considered as multipole expansions of radiation operators, and focus the fields to higher order multipole radiations. We described the effective number of multipoles that are the major contributions to the scattered fields which are useful in successful application of MLSM. Fresnel data set has been used for the study.