The shoreward and seaward propagating tidal wave components were determined using four co-located pressure and velocity sensors longitudinally deployed in Elkhorn Slough, Monterey Bay, CA, to describe tidal wave evolution and distortion. Elkhorn Slough is short, reflective (100%) estuary consisting of a narrow, gently sloping main channel and vast marsh and mud flats near the landward boundary. The amplitude reflection for the astronomical tidal constituent is 90%, whereas the distortion,...

Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *ELECTROMAGNETIC WAVE REFLECTIONS,...

This report covers 1960-63 results on oblique incidence, satellite scintillation, D region scatter, shape of irregularities in D + E regions, flutter fading, and direct back-scatter from the F region.

Topics: DTIC Archive, Clemesha, B R, GHANA UNIV LEGON, *IONOSPHERIC DISTURBANCES, ELECTROMAGNETIC WAVE...

Topics: DTIC Archive, ISTITUTO NAZIONALE DI GEOFISICA ROME (ITALY), *IONOSONDES, ITALY, ELECTROMAGNETIC...

Topics: DTIC Archive, PARKE MATHEMATICAL LABS INC CONCORD MA, *MICROWAVE OPTICS, ELECTROMAGNETIC WAVE...

In recent years the optical properties of particles near or on a plane surface have been the subject of several papers that deal with both the theoretical and the experimental aspects of the problem. This interest from the scientific community can be easily understood because revealing through optical measurements the presence of particles on a surface that is expected to be clean is of great importance both for industry for medicine. Among the theoretical techniques that have been proposed to...

Topics: DTIC Archive, Borghese, F, MESSINA UNIV (ITALY), *LIGHT SCATTERING, *OPTICAL PROPERTIES,...

The diffraction of plane electromagnetic waves by ideally conducting bodies, the surface of which have discontinuities, is investigated in the report. The linear dimensions of the bodies are assumed to be large in comparison with the wavelength. The method developed takes into account the perturbation of the field in the vicinity of the surface discontinuity and allows one to substantially refine the approximations of geometric and physical optics. Expressions are found for the fringing field...

Topics: DTIC Archive, Ufimtsev, P Ya, FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSONAFB OH, *DIFFRACTION, USSR,...

Exact solutions for the reflection and transmission coefficients are obtained for two general electron density distributions: kinked-trapezoid and exponential-homogeneous-exponential. Normal incidence into a stratified plasma slab is assumed so that the electromagnetic waves are propagating parallel to the free electron density gradients. A constant magnetic field is applied in the propagation direction. The solutions derived on this basis are used to evaluate the effect of the more realistic...

Topics: DTIC Archive, Gold, Richard R, AEROSPACE CORP EL SEGUNDO CA, *ELECTROMAGNETIC WAVE REFLECTIONS,...

A number of problems arising at designing and the analysis of dielectric rod antennas is reviewed. The complex propagation constants for the HE(11) wave in a dielectric rod are obtained. The field distribution along the rod of finite length with allowance for reflections from the rod ends is analyzed.

Topics: DTIC Archive, Buharov, S. V., DNEPROPETROVSK NATIONAL UNIV (UKRAINE), *WAVE PROPAGATION, *ANTENNAS,...

For convex non-depolarizing bodies, the monostatic-bistatic approximation is exact to first order terms in the bistatic angle. The second order error effect causes widening of the lobe structure with increasing bistatic angle. For depolarizing bodies, the error is again second order in the bistatic angle provided that the depolarizing edges have parallel orientation. Consequently, the theorem can be extended to convex bodies of revolution.

Topics: DTIC Archive, MITRE CORP BEDFORD MA, *POLARIZATION, *MAGNETOOPTICS, ELECTROMAGNETIC WAVE...

The backscatter from conducting and dielectric spheres, and to a lesser extent from conducting spheres with a relatively thin dielectric coating, is considered in the time domain. Utilizing rigorously computed values of the amplitude and phase of the continuous wave backscatter, short pulses of electromagnetic waves are synthesized by Fourier series. The resultant returns are examined as a function of time, and the individual returns compared with some approximate theories.

Topics: DTIC Archive, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *SPHERES, *ELECTROMAGNETIC WAVE...

Plane wave reflection from soft and hard surfaces coated by chiral material has recently been analyzed for normal incidence. In this study, the plane wave reflection from a uniaxial chiral slab backed by soft and hard surfaces is formulated for normal incidence and the polarization properties of the reflected field are investigated.

Topics: DTIC Archive, Ogucu, G., Uckun, S., GAZIANTEP UNIV (TURKEY) DEPT OF ELECTRICAL AND ELECTRONICS...

An analytic method for the reconstruction of the profiles of refractive indices of inhomogeneous, stratified regions is presented. The reflection coefficient, r(k), for time-harmonic electromagnetic waves is represented as a rational function of k, the wave number. One-dimensional inverse scattering theory has been applied to obtain analytic, closed-form expressions for the profile functions, q(x), from r(k). The profile reconstruction method is demonstrated with a three-pole r(k), the yields...

Topics: DTIC Archive, Jordan,Arthur K, NAVAL RESEARCH LAB WASHINGTON D C, *ELECTROMAGNETIC SCATTERING,...

The agile mirror plasma has the capability of redirecting microwave beams electronically. It is now well established that the plasma is a beam generated plasma, where the beam is generated by a hollow cathode discharge. A new hollow cathode mode of operation, called the enhanced glow mode has recently been established. The main difficulty in understanding the enhanced glow is the behavior of the cathode plasma. This work is an initial attempt at a theory of the cathode region of the enhanced...

Topics: DTIC Archive, Manheimer, Wallace M., NAVAL RESEARCH LAB WASHINGTON DC FUNDAMENTAL PLASMA PROCESSES,...

The backscattering cross section and pattern of wires 2 to 18.5 wavelengths long were theoretically computed and plotted. Assuming a spherically random orientation of the wire, the report presents the average cross sections and probability distributions for various lengths and radii of the wire.

Topics: DTIC Archive, Hong, Soonsung, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *ELECTROMAGNETIC...

The electromagnetic properties of an artificial layered material with negative permittivity and permibility are studied analytically. To analyses the translation matrix method is employed The translation matrix for multilayered structure is found in analytical form. The reflection and propagation coefficients of multilayered plate arc written in analytical form. The propagation conditions of a wave within periodic layered structure with negative parameters are obtained in analytical form.

Topics: DTIC Archive, Vytovtov, K., DNIPROPETROVSK NATIONAL UNIV (UKRAINE)DEPT OF RADIOPHYSICS,...

The local theory of singular points is extended to a large class of linear, second-order, ordinary differential equations which can be physical Schroedinger equations or govern the modulation of real oscillators or waves. In addition to Langer's fractional turning points, such equations admit highly irregular points at which the coefficients of the differential equation can be almost arbitrarily multivalued. Genuine coalescence of singular points, however, is not considered. A local...

Topics: DTIC Archive, Meyer,R E, WISCONSIN UNIV-MADISON MATHEMATICS RESEARCH CENTER, *OSCILLATORS,...

An electromagnetic wave full-wave solution to the rough surface scattering problem is presented. The mathematical model is derived for vertically and horizontally polarized field components by diffuse single and double-scatter cross sections of random rough surfaces. The model comprises terms of multidimensional integral expressions. Both physical optics and small perturbation solutions can be obtained from the full-wave model.

Topics: DTIC Archive, Bahar, Ezekiel, NEBRASKA UNIV LINCOLN, *POLARIZATION, *ELECTROMAGNETIC WAVE...

The Dyadic Green's Functions (DGF) of a two-layer biaxially anisotropic medium are derived. The principal coordinate system of the anisotropic medium is allowed to have arbitrary orientation with respect to the layer geometry. The formulation is based on the unbounded Dyadic Green's Function derived in Part I of the sequel. Using the matrix method the coefficients of the two-layer DGF are expressed in terms of half-space Fresnel reflection and transmission coefficients. To complete this...

Topics: DTIC Archive, Mudaliar, Saba, ARCON CORP WALTHAM MA, *GREENS FUNCTIONS, *ELECTROMAGNETIC WAVE...

Ionospherically propagated ground-backscatter signals in the 10-to- 30-MHz frequency band have been used for decades as a means for studying the earth's ionosphere. Long pulse lengths and wide antenna beamwidths have resulted in backscatter echoes that were spatially averaged enough to give ambiguous information about the ionosphere. The purpose of this research is to explore experimentally how a backscatter sounder having high resolution in time delay (3 microsec) and in azimuth (1/2 deg)...

Topics: DTIC Archive, Washburn, Taylor W, STANFORD RESEARCH INST MENLO PARK CA, *ATMOSPHERIC SOUNDING,...

Topics: DTIC Archive, Waniek, Ralph W, ADVANCED KINETICS SANTA ANA CA, *MAGNETIC FIELDS, *PLASMAS(PHYSICS),...

The reflection of electromagnetic waves normally incident on the wavefronts of a semi-infinite standing sound wave is discussed. By analogy with the Bragg reflection in optics, a maximum reflection occurs when the wavelength of the electromagnetic radiation in the sound perturbed region is twice the acoustic wavelength. Since the reflecting planes of maximum sound pressure disappear periodically, the reflected electromagnetic signal is modulated with the sound frequency. An experiment is...

Topics: DTIC Archive, Schmitt, H J, HARVARD UNIV CAMBRIDGE MA CRUFT LAB, *ELECTROMAGNETIC WAVE REFLECTIONS,...

The purpose of this research note is to show that a simple relation exists between the spectrum of surface elevations and the spectrum of surface slopes. This relation is useful when working on the problem of electromagnetic wave scattering from rough surfaces. When using the small perturbation theory to compute scattered fields from a rough surface, both the spectrum of surface elevations and the spectrum of surface slopes can appear in the final equations. The spectrum of the surface...

Topics: DTIC Archive, Hevenor, Richard A, ARMY ENGINEER TOPOGRAPHIC LABS FORT BELVOIR VA, *ELECTROMAGNETIC...

The high-frequency electromagnetic pulse radiation from nuclear explosions presents a possible detection mechanism for low-altitude or ground bursts as well as for bursts in outer space. This radiation propagates around the earth via ground wave or ionospheric reflection, and it is necessary to determine what effect this propagation will have on the received signals. The Memorandum first considers the attenuation of the pulse when it travels via ground wave. Effects of the height of the source...

Topics: DTIC Archive, RAND CORP SANTA MONICA CA, *ELECTROMAGNETIC RADIATION, *NUCLEAR EXPLOSIONS,...

Reflection and transmission characteristics of double-layer two-periodic gratings of perfectly conducting infinite strips with a complex shape are considered. The structures with layers that have strips turned on 90 degrees and parallel are considered. The comparison of reflection properties of double-layer two-periodic gratings of straight-line strips with curvilinear ones is presented.

Topics: DTIC Archive, Mladyonov, P. L., UKRAINIAN ACADEMY OF SCIENCES KHARKOV INST OF RADIO ASTRONOMY,...

In this paper we calculate the optimum parameters of a stratified periodic structure. We obtained the dependences of intensity, ellipticity and angle of turn of the main axis of polarization ellipse of reflected and transmitted waves on the quantity of the cells, on the frequency of the electromagnetic waves and on the magnetic field strength. We show there is the possibility of use of such structure, having selective reflection of electromagnetic waves, as the polarization converter controlled...

Topics: DTIC Archive, Samchenko, I. V., Kaganovich, V. E., GOMEL STATE UNIV (BELARUS) DEPT OF GENERAL...

A plane-parallel homogeneous bianisotropic plate under an oblique incidence of a plane harmonic wave is considered. The bianisotropy axis is not coincide with a normal to a plate. The propagation and reflection coefficients are found in the analytical form.

Topics: DTIC Archive, Vytovtov, K., DNIPROPETROVSK NATIONAL UNIV (UKRAINE)DEPT OF RADIOPHYSICS,...

In certain applications involving reflection from smooth convex surfaces, the conventional geometrical optics method (GO) is not sufficiently accurate. In this paper a generalization of the conventional GO formulas is presented and closed-form expressions are derived. The derivation of the generalized geometrical optics (GGO) forumulas is based on the Fresnel transformation between two planes, one of which contains the spectral point, while the other passes through the observation point. The...

Topics: DTIC Archive, Mittra ,R, ILLINOIS UNIV AT URBANA-CHAMPAIGN ELECTROMAGNETICS LAB, *ELECTROMAGNETIC...

In order to solve FD-TD electromagnetic radiation and scattering problems in free space, the computational grid should be truncated at some finite distance to simulate the solution for an infinitely large grid. One way to emulate an infinite grid is to absorb outgoing waves incident onto the grid boundary such that there is no reflection back into the grid. Waves incident to the boundary must 'exit' the grid boundary without affecting the solution within the grid. Based on this idea, this...

Topics: DTIC Archive, Wang, Kewjin, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *ELECTROMAGNETIC WAVE...

In the past the lateral wave has been investigated for the case of a sharply bounded transition layer and a layer with a linear velocity variation. The interpretation of the lateral wave given in these instances cannot be extended to an arbitrary smooth layer, and in many cases, the exact nature of the lateral wave contribution becomes unclear. It is our purpose to clarify these matters and to present the characteristics of lateral wave propagation on a layer of arbitrary variation. The models...

Topics: DTIC Archive, Lang, Roger, POLYTECHNIC INST OF BROOKLYN FARMINGDALE NY DEPT OF ELECTROPHYSICS,...

In an empty halfspace a point source emits electromagnetic waves of fixed frequency and arbitrary polarization. The fields reflected by an imperfectly conducting plane, characterized by a constant, isotropic surface impedance, are determined by means of the geometrical optics approximation. An optimization method is used to compute the surface impedance, which minimizes a given function of the e.m. fields (e.g. the average energy density) at a given observation point. The properties of the...

Topics: DTIC Archive, Bridges,T J, WISCONSIN UNIV-MADISON MATHEMATICS RESEARCH CENTER, *ELECTROMAGNETIC...

In previous papers, some applications of the principle of invariant imbedding to radiative transfer and neutron diffusion processes were presented. This use of invariance principles was stimulated by the fundamental work of Ambarzumian and Chandrasekhar, and strongly influenced by the point of regeneration technique of Bellman and Harris, and the theory of dynamic programming. Fundamental for the success of these techniques as applied to the above processes is the ability to consider the...

Topics: DTIC Archive, RAND CORP SANTA MONICA CA, *ELECTROMAGNETIC RADIATION, *ELECTROMAGNETIC WAVE...

The reflections on helicopter canopies from instrument panel light sources adversely affect night flight operations. A program objective was to investigate the application of Light Control Film, such as 3M or equivalent material, as a technique for eliminating helicopter canopy reflections in the AH-1S from instrument panel lighting which cause the pilot and copilot night flight operational problems. A mock-up of the AH-1S was used to test and evaluate the reflection conditions. Light control...

Topics: DTIC Archive, Piccione,Dino, BOEING VERTOL CO PHILADELPHIA PA, *HELICOPTERS, *ELECTROMAGNETIC WAVE...

Tables of electromagnetic wave reflection functions.

Topics: DTIC Archive, ARMY MISSILE RESEARCH DEVELOPMENT AND ENGINEERING LAB REDSTONE ARSENAL AL ADVANCED...

In 1984, Burns Harbor was nominated for inclusion in the Monitoring Completed Navigation Projects Program sponsored by Headquarters, U.S. Army Corps of Engineers. Burns Harbor was approved for monitoring in 1985 because it met both generic and site-specific selection criteria. This report summarizes the monitoring effort that took place at Burns Harbor. An overview of the monitoring effort is presented, included background information, a description of the monitoring effort, results of...

Topics: DTIC Archive, McGehee, David, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS COASTAL...

Electromagnetic reflection from the walls of the vacuum chamber of a satellite simulator may be reduced by placing one or more grids of wires having known impedances just inside the conducting wall. This report presents the results of a parameter study on the effect of wire spacing and wire resistance and inductance on the frequency dependence of the reflection coefficient of a wall with such a grid in front of it. This data should be useful in helping to choose good values of the design...

Topics: DTIC Archive, Latham,R W, TETRA TECH INC PASADENA CALIF, *ELECTROMAGNETIC WAVE REFLECTIONS,...

Detailed scans of x-band microwave transmission, reflection and noise emission of various Agile Mirror plasma sheets as a function of frequency have been performed. The reflected microwave signal from the plasma sheet is compared to that reflected from an aluminum plate with the same dimensions as the plasma. Estimates of the electron density are made by measuring the transmission through plasma sheets that are then compared to x-band wavelengths. The noise spectrum is mapped, and mechanisms...

Topics: DTIC Archive, Murphy, D. P., NAVAL RESEARCH LAB WASHINGTON DC, *PLASMAS(PHYSICS), *MICROWAVE...

An analysis is made of electromagnetic propagation through a homogeneous, isotropic, and slightly ionized plasma slab. Exact solutions for the reflection and transmission coefficients are given as functions of slab thickness, incident angle, and plasma wave number. Two approximations are introduced which allow the plasma slab to become a thin current sheet. When the approximations are valid, the reflection and transmission coefficients for the thin plasma are a function of the sheet surface...

Topics: DTIC Archive, Smith, T M, AEROSPACE CORP EL SEGUNDO CA, *PLASMA WAVES, *ELECTROMAGNETIC WAVE...

A deficiency is pointed out in Stevenson's method of reducing the solution of electromagnetic scattering problems to a succession of standard potential problems whose solutions determine terms in the low frequency expansion of the scattered field. An alternate approach is presented, for perfectly conducting scatterers, which not only removes the difficulty but also is simpler and more explicit than Stevenson's method. The details of the analogous, though simpler, scalar scattering problems are...

Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR RADIATION LAB, *ELECTROMAGNETIC RADIATION, *POTENTIAL THEORY,...

The validity of the Born approximation for determination of the reflection coefficients of plasma slabs is numerically examined for two cases: the uniform underdense plasma slab and a plasma slab with a sunusodial electron density perturbation superimposed on a constant electron density. The regions of validity of the Born approximation are discussed in each case.

Topics: DTIC Archive, Zivanovic, S, GM DEFENSE RESEARCH LABS SANTA BARBARA CA, *ELECTROMAGNETIC WAVE...

A study was made of the probability distribution of losses from reflections at discontinuities in a transmission line, on the assumption that the reflection coefficients at the discontinuities have random phase, and, in addition, random magnitudes associated with manufacturing uncertainties (tolerances).

Topics: DTIC Archive, Marsaglia, George, BOEING SCIENTIFIC RESEARCH LABS SEATTLE WA, *TRANSMISSION LINES,...

An investigation of inverse problems as basic problems in science, in which physical systems are to be identified on the basis of experimental observations. These problems are especially important in astrophysics and astronomy, for their objects of investigation are frequently not observable in a direct fashion. Solar and stellar structure, for example, is estimated from the study of spectra, while the structure of a planetary atmosphere may be deducted from measurements of reflected sunlight....

Topics: DTIC Archive, RAND CORP SANTA MONICA CA, *CELESTIAL MECHANICS, *ELECTROMAGNETIC WAVE REFLECTIONS,...

The results of the numerical analysis of reflecting and transmitting properties of multi-layered structures composed of doubly periodic arrays of metallic strips are presented in the paper. Strip elements have been selected, having a shape of letters C, S and OMEGA. The strips of the arrays are placed on a thin dielectric substrate. Strip elements can have bulk impedance loading, included in the break of strip. The interference of multi-layered array systems, due to multiple reflections of...

Topics: DTIC Archive, Prosvirnin, S. L., Zouhdi, S., UKRAINIAN ACADEMY OF SCIENCES KHARKOV INST OF RADIO...

The problem of electromagnetic wave scattering from a random medium layer with a random interface is considered. The layer has planar boundaries on the average. Assuming that both the random perturbation of the interface and the random fluctuations of permittivity of the medium are small, a first-order perturbation solution to the scattered field is obtained. The bistatic scattering coefficients are calculated and expressed in a compact and meaningful form consisting of various terms that can...

Topics: DTIC Archive, Mudaliar, Saba, ROME LAB HANSCOM AFB MA, *SCATTERING, *MICROWAVES, *ELECTROMAGNETIC...

The contractor investigated the use of frequency modulated (FM), band limited noise signals and other applicable techniques to increase the speed of making coupling and shielding effectiveness measurements in reverberation chambers; developed the most promising techniques and analytical approaches for usable methodologies to predict the effect of electromagnetic fields on the operational performance of electronic systems; and developed and investigated new assessment techniques using...

Topics: DTIC Archive, Quine, John P., CALSPAN UB RESEARCH CENTER BUFFALO NY, *ELECTROMAGNETIC...

The complex electroacoustic wave impedance is examined and is related to power coupling at a plasma-vacuum boundary via the plane wave solution of Maxwell's equations. The reactive component of impedance is found to be important at frequencies less than the plasma frequency, where it contributes a significant amount to power flow. Thus at those frequencies serious errors can be introduced by assuming that the electroacoustic power is made up of the powers in the incident and reflected waves...

Topics: DTIC Archive, Gallawa, Robert L., INSTITUTE FOR TELECOMMUNICATION SCIENCES AND AERONOMY BOULDER CO,...

An appropriate form of the sea surface wave height spectrum is discussed.

Topics: DTIC Archive, Wagner, Richard J, TRW SYSTEMS GROUP REDONDO BEACH CA THEORETICAL PHYSICS GROUP,...

A new and more direct approach to the connection of wave amplitudes across turning points and singular points of physical Schroedinger equations is summarized. It interprets the connection formulae as an asymptotic expression of the branch structure of the singular point. It also extends turning-point theory to almost the whole class of singular points of physical wave- or oscillator-equations by a new approach to irregular singular points of ordinary differential equations. This reveals an...

Topics: DTIC Archive, Meyer,R E, WISCONSIN UNIV-MADISON MATHEMATICS RESEARCH CENTER, *SCHRODINGER EQUATION,...

An experimental investigation of a linear Van Atta reflector consisting of four half-wave dipoles was made in a radio-anechoic box. In agreement with a theoretical and numerical investigation, the experiments show that the reflector has the effect stated in Van Atta's patent description only to a limit extent. It was confirmed that maximum reflection in many cases is not back in the direction of incidence and that the reflector has a mirror effect to the same extent as it has the Van Atta...

Topics: DTIC Archive, TECHNICAL UNIV OF DENMARK LYNGBY LAB OF ELECTROMAGNETIC THEORY, *ELECTROMAGNETIC WAVE...

Periodic layered structures are considered. Each layer of the structure is an array of plane metal strips of complex shape placed on a dielectric substrate. The frequency dependencies of eigenwave propagation constants have been obtained. The reflection coefficients from the half-space filled by such medium have been studied. The results for structures made of identical layers and for structures composed of pairs of different layers are presented.

Topics: DTIC Archive, Prosvirnin, Sergey L., Tyrnov, Dmitry O., UKRAINIAN ACADEMY OF SCIENCES KHARKOV INST...

Topics: DTIC Archive, PON, C Y, CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB, *DIELECTRICS,...