Characteristic Basis Function Method for Solving Electromagnetic Scattering Problems Over Rough Terrain Profiles

Abstract

A computationally efficient algorithm, which combines the characteristic basis function method (CBFM), the physical optics (PO) approach (when applicable) with the forward backward method (FBM), is applied for the investigation of electromagnetic scattering from-and propagation over-large-scale rough terrain problems. The algorithm utilizes high-level basis functions defined on macro-domains (blocks), called the characteristic basis functions (CBFs) that are constructed by aggregating low-level basis functions (i.e., conventional sub-domain basis functions). The FBM as well as the PO approach (when applicable) are used to construct the aforementioned CBFs. The conventional CBFM is slightly modified to handle large-terrain problems, and is further embellished by accelerating it, as well as reducing its storage requirements, via the use of an extrapolation procedure. Numerical results for the total fields, as well as for the path loss are presented and compared with either measured or previously published reference solutions to assess the efficiency and accuracy of the algorithm. Index Terms-Characteristic basis functions (CBFs), method of moments (MoM), forward-backward method (FBM), electromagnetic scattering, terrain propagation.

Tabulated interaction method for electromagnetic scattering from lossy irregular terrain profiles

“…The selected terrain profiles, namely Hjorring and Hadsund terrain profile are from Denmark. Figure (2) and (3) show that the fields computed by the TIM matches the field computed by CBFM-FBM. Moreover, a comparison versus measured field strength is also given in figure (2) and (3).…”

“…In this section, a comparison between the TIM and the CBFM-FBM [2], [3] is performed in terms of accuracy and processing time. The group size of CBFM is 50m.…”

“…The group size of CBFM is 50m. In the CBFM-FBM, two basis functions, primary basis functions (PBFs) and secondary basis functions (SBFs), were used to construct the currents on the surface [3]. The field generated by the TIM and the CBFM are shown in figure (2) and figure (3).…”

“…The efficient numerical solution of these equations is a key topic in computational electromagnetics. Different techniques have been developed including iterative methods: Forward Backward Method (FBM) [4], Forward Backward Method with Spectral Acceleration (FBM-SA) [5], [6], acceleration methods such as the Fast Far Field Appoximation (FAFFA) [7], and compression techniques such as the Characteristic Basis Function Method (CBFM) [2], [3], etc. The Tabulated Interaction Method (TIM) is related to both the FAFFA and the CBFM and in this work we extend it, considering the propagation over lossy irregular terrain profiles.…”

Analysis of electromagnetic scattering from an object above rough surface by using characteristic basis functions and ACA scheme

“…Recently, Raj Mittra et al developed an efficient numerical method, CBFs method, to scattering of rough terrain profiles [9]. The CBFs are constructed by aggregating low-level basis functions, which consist of primary basis functions (PBFs) and secondary basis functions (SBFs).…”