Space-Frequency Sampling Criteria for Electromagnetic Scattering of a Finite Object

摘要

This investigation concerns the sampling criteria in the wave number space for generating the spatial impulse response of a finite target. The impulse response of a finite target is important for target identification and imaging. The other purpose of this report is in the management of large amounts of data for potential application in the presentation of scattered field data and construction of such images. For clarity, monostatic impulse responses of up to two dimensions are considered. A proper choice of canonical confinement for the target in space can greatly reduce the number of samples required to sufficiently characterize the target's spatial impulse response. One dimensional impulse responses generated using two basic types of confinement: 1) isotropic and 2) parallelepiped, are compared. The two approaches show competitive reconstructed results. Though a sampling lattice may be more efficient in the sense of a reduced number of measurement points, it may be less effective when digital processing is involved. Specifically, the time consuming interpolation step is required to put data presented in other types of sampling lattice into the cubic type. Two dimensional impulse responses reconstructed from cubic sampled data are compared with those using Mensa et al.'s method. Two dimensional impulse responses obtained also indicate good potentials for image reconstruction via the spatial impulse response.