Accession Number:

ADA288512

Title:

Application of the Measured Equation of Invariance to Wave Propagation over Irregular, Inhomogeneous Terrain.

Descriptive Note:

Technical rept. 1 Oct 92-1 Oct 93,

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF ELECTRICAL AND COMPUTER ENGINEE RING

Personal Author(s):

• Janaswamy, Ramakrishna

Report Date:

1993-10-01

Pagination or Media Count:

65.0

Abstract:

The problem of propagation of electromagnetic waves over irregular, inhomogeneous terrain is solved by a finite difference scheme. The method is fast and requires considerably less memory compared to the integral equation methods. The method requires a storage space of order 0N and an execution time of order 0N2. Fields generated by a TEz line source are represented in an integral form in terms of the field over a fiat, constant impedance plane, and the field scattered by the terrain irregularities and inhomogeneities. Accurate expressions are provided for the incident field and the Greens function, whose evaluation is otherwise accomplished by the rather time-consuming Sommerfelds integrals. Measured equation of invariance is used to terminate the mesh. The sparse matrix generated by the method is inverted using Ricatti transform. Numerical results are presented for the ground wave as well as the sky wave. Comparison is made for known geometries to establish the validity and limitations of the method.

Descriptors:

• *ELECTROMAGNETIC WAVE PROPAGATION
• *FINITE DIFFERENCE THEORY
• MATHEMATICAL MODELS
• MAGNETIC FIELDS
• COMPUTATIONS
• TWO DIMENSIONAL
• FINITE ELEMENT ANALYSIS
• COMPARISON
• ELECTROMAGNETIC SCATTERING
• TERRAIN
• BACKSCATTERING
• ELECTROMAGNETIC RADIATION
• SPARSE MATRIX
• GREENS FUNCTIONS
• GROUND WAVES(ELECTROMAGNETIC)
• INTEGRAL EQUATIONS
• INVARIANCE
• SKY WAVES
• ELECTRICAL IMPEDANCE
• ANTENNA RADIATION PATTERNS

Subject Categories:

• Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE