Calculation of Impedance Matrix Inner Integral to Prescribed Precision
Abstract
We present a new method for evaluating the inner integral of the impedance matrix element in the traditional Rao-Wilton-Glisson formulation of the method of moments for perfect conductors. In this method we replace the original integrand (modified by a constant phase factor) by its Taylor series and keep enough terms to guarantee a number of significant digits in the integration outcome. We develop criteria that relate the number of Taylor terms to the number of required significant digits. We integrate the leading Taylor terms analytically and the rest through iteration formulas. We show that the iteration formulas converge for all observation points within a sphere with a radius of half-a-wavelength and center the triangle's centroid. We compare results of our method with existing ones and find them in excellent agreement. Outside this sphere, we employ a set of triangle cubatures of increasing size together with a convergence criterion to determine the integration outcome to a prescribed number of significant digits. By designing appropriate numerical experiments using a set of 25 triangles and about 10,000 observation points, we define spherical regions of space where a cubature of minimum size will provide a desired number of significant digits. The approach is quite general but we demonstrate it explicitly by using seven significant digits as the required accuracy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 18, 2008
- Accession Number
- ADA491811
Entities
People
- John S. Asvestas
- Oliver E. Allen
- Stephen Yankovich
Organizations
- Naval Air Warfare Center