TY - JOUR
T1 - A transport theory of pulse propagation in a strongly forward scattering random medium
AU - Whitman, Gerald M.
AU - Schwering, Felix
AU - Triolo, Anthony A.
AU - Cho, Nack Y.
N1 - Funding Information:
Manuscript received November 21, 1994; revised September 18, 1995. This work was supported by the U.S. Army Research contract DAAL03-86-D-000 1. G. M. Whitman and A. A. Triolo are with the Electrical and Computer Engineering Department, New Jersey Institute of Technology, Newark, NJ 07102 USA. F. Schwering is with the Space and Terrestrial Communications Directorate, CECOM, Fort Monmouth, NJ 07703 USA. N. Y. Cho is with the Satellite Business Division of Hyundai Electronics Industries Co., Ltd., Seoul, Korea. Publisher Item Identifier S 0018-926X(96)00627-8.
PY - 1996
Y1 - 1996
N2 - The scalar time-dependent equation of radiative transfer is used to develop a theory of pulse propagation in a discrete random medium whose scatter function (phase function) consists of a strong, narrow forward lobe superimposed over an isotropic background. The situation analyzed is that of a periodic sequence of plane-wave pulses, incident from an air half-space, that impinges normally upon the planar boundary surface of a random medium half-space; the medium consists of a random distribution of particles that scatter (and absorb) radiation in accordance with the aforementioned phase function. After splitting the specific intensity into the reduced incident and diffuse intensities, the solution of the transport equation in the random medium half-space is obtained by expanding the angular dependence of both the scatter function and the diffuse intensity in terms of Legendre polynomials, and by using a point matching procedure to satisfy the boundary condition that the forward traveling diffuse intensity be zero at the interface. Curves of received power show that, at small penetration depths, the coherent (reduced incident) intensity dominates, whereas at large depths, the incoherent (diffuse) intensity is the strongest and causes the pulses to broaden and distort. The motivation for this study was to complement a test series, on mm-wave pulse propagation in vegetation, by a theory that provides understanding of overall trends and assistance in the interpretation of measured results. In the mm-wave region, all scatter objects in a forest have large dimensions compared to a wavelength and, therefore, produce strong forward scallering and a phase function of the type assumed in this paper.
AB - The scalar time-dependent equation of radiative transfer is used to develop a theory of pulse propagation in a discrete random medium whose scatter function (phase function) consists of a strong, narrow forward lobe superimposed over an isotropic background. The situation analyzed is that of a periodic sequence of plane-wave pulses, incident from an air half-space, that impinges normally upon the planar boundary surface of a random medium half-space; the medium consists of a random distribution of particles that scatter (and absorb) radiation in accordance with the aforementioned phase function. After splitting the specific intensity into the reduced incident and diffuse intensities, the solution of the transport equation in the random medium half-space is obtained by expanding the angular dependence of both the scatter function and the diffuse intensity in terms of Legendre polynomials, and by using a point matching procedure to satisfy the boundary condition that the forward traveling diffuse intensity be zero at the interface. Curves of received power show that, at small penetration depths, the coherent (reduced incident) intensity dominates, whereas at large depths, the incoherent (diffuse) intensity is the strongest and causes the pulses to broaden and distort. The motivation for this study was to complement a test series, on mm-wave pulse propagation in vegetation, by a theory that provides understanding of overall trends and assistance in the interpretation of measured results. In the mm-wave region, all scatter objects in a forest have large dimensions compared to a wavelength and, therefore, produce strong forward scallering and a phase function of the type assumed in this paper.
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U2 - 10.1109/8.477536
DO - 10.1109/8.477536
M3 - Article
AN - SCOPUS:0029771713
SN - 0018-926X
VL - 44
SP - 118
EP - 128
JO - IEEE Transactions on Antennas and Propagation
JF - IEEE Transactions on Antennas and Propagation
IS - 1
ER -