Deconvolution of target signature for a scene with bistatic impulse radiating antennas and a sphere
A model for an impulse radiating antenna (IRA) has been developed in WIPL-D. A scene using a bistatic pair of these IRAs is modeled with a sphere target and is simulated in the frequency domain. The input to the antenna is a Gaussian pulse, and the current on the receive antenna is plotted vs. frequency. This receiver response is proportional to the scattered field from the sphere. The frequency domain data are processed to give the time domain response. The objective of this work is to deconvolve the signature of the scatterer from the receiver transient response. Additional separate simulations for each scene component and electromagnetic interaction were needed and were performed using WIPL-D. The process is successful for this scene, which does not include a ground plane. The analysis of the simulated data and deconvolution of the target signature are done in Matlab.
Analysis of the impulse radiating antenna
A procedure is developed for analyzing the radiation on the impulse radiating antenna. High- and low-frequency asymptotes for the radiation on axis are developed, and comparison to a wire-grid model run under the Nuclear Electromagnetics Code is favorable. These preliminary results indicate no late-timing ringing of the radiated waveform.<<ETX>>
EIGER: Electromagnetic Interactions GEneRalized
EIGER (Electromagnetic Interactions GEneRalized), a single integrated software tool set, brings together a variety of spectral domain analysis methods. These include moment method solutions of integral equation formulations and finite elements solutions of partial differential equations. New software engineering methods, specifically, object oriented design, are being used to implement abstractions of key components of spectral analysis methods so that the tools can be easily modified and extended to treat new classes of problems. The key components of the numerical analysis tool, and their roles, are: elements-to describe the geometry, basis functions-to interpolate the unknowns (e.g., fields) locally, and operators-to express the underlying physics formulations used to propagate the energy or enforce fundamental principals. The development of EMPACK by Yesantharao (1989) provided the fundamental impetus for these abstractions which are discussed.