J. Galejs

United States Naval Research Laboratory

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Michael H. Mentzoni

University of Oslo

S. R. Seshadri

Manipal Academy of Higher Education

R. Row

Applied Research Laboratory at the University of Hawai‘i

W. B. Cowan

University of Waterloo

A.L. Cullen

Culham Science Centre

Ronold W. P. King

Harvard University

T. W. Thompson

Jet Propulsion Laboratory

V. Fock

Pushkin Leningrad State University

Cooperative Institutions

Applied Research Laboratory at the University of Hawai‘i

McGill University

Jet Propulsion Laboratory

California Institute of Technology

Sylvana Research

Harvard University Press

University of Waterloo

National Research Council Canada

Manipal Academy of Higher Education

Kasturba Medical College, Manipal

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V.L.F. PROPAGATION

Elsevier eBooks (1972)

J. Galejs

Phase velocity

Group velocity

10.1016/b978-0-08-016710-7.50013-2

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Citations (17)

Admittance of insulated loop antennas in a dissipative medium

IRE Transactions on Antennas and Propagation (1965)

J. Galejs

A small circular loop antenna is located in an insulating layer within a dissipative medium. The admittance of the loop is calculated using a two-term trial function for the loop current in a variational formulation. Thin insulating layers tend to maintain a nearly uniform current around the small loop, in particular for highly lossy surrounding media. The assumption of a uniform loop current is shown to be justified for a range of antenna parameters.

Admittance

Loop antenna

Lossy compression

10.1109/tap.1965.1138398

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Citations (19)

SLOT ANTENNAS IN FREE SPACE

Elsevier eBooks (1969)

J. Galejs

Free space

10.1016/b978-0-08-013276-1.50008-9

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Citations (2)

Excitation of slots in a conducting screen above a lossy dielectric half space

IRE Transactions on Antennas and Propagation (1962)

J. Galejs

A slot in a conducting screen which separates a lossless from a lossy dielectric half space is excited by a current source which lies in the interface between the two media. This geometry idealizes slot antennas constructed by placing wire mesh on the ground surface or island antennas as proposed by Morgan and Gould. For narrow slots of width \omega<\delta ( \delta =skindepth in the lossy medium) the transverse distribution of the electric field in the slot plane is approximated by the static solution. The langitudinal distribution of the potential across the slot is obtained from a Hallén type solution of an integral equation. For slots of negligible width the propagation constant along the slot approaches the propagation constant of a thin wire which lies in the interface between the two dielectrics. For wide slots of \omega\gg\delta the integral equation can be solved for the longitudinal variation of the transverse electric field by Fourier transforms, provided that the variation of the electric field in the transverse direction is negligible. The electric field exhibits approximately the same longitudinal variation in the slot plane as the electric field in a direction transverse to the axis of an infinitely long line current which lies in the interface of the two dielectrics. The radiation efficiency of the wide slot ( \omega>\delta ) is larger than the radiation efficiency of narrow slots ( \omega<\delta ). Still, the expected efficiency of the wide slots is less than 10^{-3} for frequencies in the VLF range and below, if the ground conductivity is of the order of 10^{-3} mho per meter. This indicates an upper limit to the efficiency of an island antenna as proposed by Gould and Morgan.

Lossy compression

10.1109/tap.1962.1137891

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Citations (30)

Near fields of a linear antenna

Electronics Letters (1967)

J. Galejs

The near fields of a strip antenna in free space have been computed by modifying a variational-impedance formulation. Current distributions, which vary linearly with distance near the ends of the antenna, excite strong tangential electric fields on the antenna surface. Such surface fields are avoided by choosing the axial antenna current to vary in proportion to the square root of the distance from the antenna ends. This modification of the antenna current is not necessary, however, for field calculations at distances comparable to the antenna width. The fields parallel to the antenna surface decrease with increasing distance from the antenna near the driving point and the antenna ends, but are found to increase in an intermediate range.

Loop antenna

10.1049/el:19670421

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Citations (1)

Amplitude distributions of radio noise at ELF and VLF

Journal of Geophysical Research Atmospheres (1966)

J. Galejs

The amplitude distribution of the received noise is related to amplitude distributions of lightning discharges, which can be analytically approximated by a sum of two exponentials. The received noise is proportional to the current moment of sources and to the transfer function of the earth-to-ionosphere waveguide between the source and the receiver; it also depends on receiver bandwidth. The receiver noise is due to the integration of several atmospherics during the response time of the receiver, and its probability distribution has been related to the probability distribution of a single source waveform using the method of characteristic functions. Closed form expressions are derived in several limiting cases, but most of the results are obtained by numerical techniques. Computations show amplitude distributions of the received noise and their dependence on receiver bandwidth, source distance, and thunderstorm frequencies, and available measurements are also discussed.

Atmospherics

10.1029/jz071i001p00201

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Citations (13)

Variationally computed antenna impedances and accuracy of resulting current distributions [Correction to a previous letter]

Electronics Letters (1967)

J. Galejs

The difference between a stationary- and a nonstationary-impedance formulation is shown to become identically equal to zero if coefficients of an approximate current distribution are determined by differentiating the stationary-impedance expression. This difference cannot be used as a criterion for estimating the accuracy of a given approximate current distribution.

Zero (linguistics)

10.1049/el:19670286

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Citations (1)

Terrestrial extremely low frequency noise spectrum in the presence of exponential ionospheric conductivity profiles

Journal of Geophysical Research Atmospheres (1961)

J. Galejs

Calculations by Raemer of the terrestrial ELF noise spectrum which are based on a sharply bounded homogeneous ionosphere of frequency-dependent height and conductivity are extended to a nonhomogeneous ionosphere of exponential conductivity profile. The exponential ionosphere model provides slightly lower resonant frequencies and less damping of the resonant peaks than the sharply bounded ionosphere. The exponential model improves the agreement with noise spectrum measurements by Balser and Wagner.

Exponential decay

10.1029/jz066i009p02787

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Citations (36)

Switching of Reactive Elements in High-Q Antennas

IEEE Transactions on Communications Systems (1963)

J. Galejs

10.1109/tcom.1963.1088740

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Citations (28)

Propagation of VLF waves below a curved and stratified anisotropic ionosphere

Journal of Geophysical Research Atmospheres (1964)

J. Galejs

The surface impedances are calculated below a spherical multilayer isotropic ionosphere and below a continuously stratified cylindrical anisotropic ionosphere in the presence of a transverse magnetic field. The propagation characteristics are obtained by applying the modal equation of a spherical geometry. In another approach the planar surface impedance is referred to a height above the lower ionospheric boundary, but the attenuation rates per 1000 km computed by the two methods agree within a fraction of 1 db. The computed attenuation rates are also compared with measurements.

10.1029/jz069i017p03639

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Citations (28)