Fast far‐field approximation for calculating the RCS of large objects

Abstract

A fast far‐field approximation (FAFFA) is developed to estimate the RCS of conducting scatterers. This method accounts for the interaction between subscatterers in two ways, depending on the electrical distance between the subscatterers. The interactions of subscatterers separated by a large electrical distance are computed in three stages: (1) aggregation, which computes the total field at a group center due to the subscatterers of the group; (2) translation, which translates the field from one group center to another; and (3) disaggregation, which distributes the field in a group center to each subscatterer in the group. Two strategies are employed to accelerate the computation in the above three stages. One is the use of far‐field approximation to simplify the computation in the translation stage; the other is the use of interpolation and smoothing techniques, which reduces the complexity of aggregation and disaggregation. The overall computational complexity for a matrix‐vector multiplication is of the order of N1.33, and the memory requirement is of order N. Numerical results show that this method can predict a RCS that is very close to exact solution, and that the method can be applied to objects with very large electrical sizes. © 1995 John Wiley & Sons. Inc.

Propagation Modelling Using Integral Equation Methods to Enable Co-existence and Address Physical Layer Security Issues in Cognitive Radio

“…With the Tabulated Interaction Method [8] the integration intervals in a group are taken to be collinear and the aggregation and disaggregation stages referred to in Lu and Chew's paper [6] are performed for a range of angles of incidence and reflection, ll…”

Computation of Em Field Scattered by an Open-Ended Cavity and by a Cavity Under Radome Using the Iterative Physical Optics

“…Number of facets increases with the frequency and the dimensions of the target. That is why several studies have been made to improve the efficiency of IPO method [15][16][17][18][19][20][21][22]. One of them is based on a segmentation principle, the S-IPO method [15].…”

Acceleration of Mesh-Based Physical Optics for Electromagnetic Scattering Analysis

“…This step could be accelerated with a fast field calculation method. Indeed, this has been done using the fast far field approximation (FaFFA) [10,11], which reduces the cost to O(N 5/3 ). However, seeing that field calculation at a specified set of points can be viewed as a Method of Moments (MoM) type of matrix-vector product, the multilevel, fast multipole method (MLFMM) [12] could be used to reduce the cost of this step even further, to O(N log N ).…”