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The Astrophysical Journal, 1996
We describe a high-resolution, high-sensitivity CO(1-0) survey of a large fraction of the south-west star-forming "ring" 20 kpc in diameter in M31 made with the 14 m FCRAO telescope and its QUARRY receiver array. At the 45'' angular resolution of the telescope, the ring is resolved into giant complexes of molecular gas with typical sizes of a few ...
Loinard, L +5 more
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We describe a high-resolution, high-sensitivity CO(1-0) survey of a large fraction of the south-west star-forming "ring" 20 kpc in diameter in M31 made with the 14 m FCRAO telescope and its QUARRY receiver array. At the 45'' angular resolution of the telescope, the ring is resolved into giant complexes of molecular gas with typical sizes of a few ...
Loinard, L +5 more
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Even-arm modulated arm width spiral properties
2018 International Applied Computational Electromagnetics Society Symposium (ACES), 2018Among Frequency Independent (FI) flush-mountable antennas the modulated arm width (MAW) spiral antenna provides the simplest architecture for measuring both polarization and direction of arrival instantaneously if frequency is known. Of interest is how the improvement in detection accuracy increases with additional arms.
W. Neill Kefauver, Dejan S. Filipovic
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Astrophysics and Space Science, 1986
The response by a gaseous disc to perturbations is investigated. Spectral analysis of the resulting pattern indicates that information about the nature of the perturber is maintained only if the perturbation is strong.
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The response by a gaseous disc to perturbations is investigated. Spectral analysis of the resulting pattern indicates that information about the nature of the perturber is maintained only if the perturbation is strong.
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Four-Armed Spiral-Helix Antenna
IEEE Antennas and Wireless Propagation Letters, 2012An antenna formed by the union of a four-armed, reflective-backed spiral antenna with a top-fed quadrifilar helix, operating over the 0.35-2.6-GHz band, is presented. The antenna features a novel dual-layering scheme that allows the modal impedance of the four-armed spiral to be greatly reduced while maintaining the desirable self-complementary ...
M. J. Radway, D. S. Filipovic
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1992 Symposium on Antenna Technology and Applied Electromagnetics, 1992
An array consisting of four-by-four spiral antennas is constructed using the pair-element (PE) technique. The 3-dB axial ratio bandwidth is improved to 8.9% by the PE technique from 3.8% for an array without using the PE technique. The −14-dB return loss bandwidth is widened to 6.4% from 3.6%.
H. Nakano +4 more
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An array consisting of four-by-four spiral antennas is constructed using the pair-element (PE) technique. The 3-dB axial ratio bandwidth is improved to 8.9% by the PE technique from 3.8% for an array without using the PE technique. The −14-dB return loss bandwidth is widened to 6.4% from 3.6%.
H. Nakano +4 more
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Electromagnetics, 1994
ABSTRACT The derivation process of a pair of H-type integral equations is reviewed for a system composed of curved wires and slots. The integral equations are characterized by two kernels Π and Π#, each being expressed in closed form. The integral equations are applied to a two-arm slot spiral antenna fed by two wires.
Hisamatsu Nakano +2 more
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ABSTRACT The derivation process of a pair of H-type integral equations is reviewed for a system composed of curved wires and slots. The integral equations are characterized by two kernels Π and Π#, each being expressed in closed form. The integral equations are applied to a two-arm slot spiral antenna fed by two wires.
Hisamatsu Nakano +2 more
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Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation, 2012
A new two-arm spiral antenna topology named power-spiral with inherently low dispersion is proposed. When compared with conventional Archimedean spirals, up to 40% improved fidelity factor is achieved thus eliminating a need for auxiliary dispersion compensation circuitry.
Mohamed A. Elmansouri +1 more
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A new two-arm spiral antenna topology named power-spiral with inherently low dispersion is proposed. When compared with conventional Archimedean spirals, up to 40% improved fidelity factor is achieved thus eliminating a need for auxiliary dispersion compensation circuitry.
Mohamed A. Elmansouri +1 more
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Publications of the Astronomical Society of the Pacific, 1990
Pulsars are used to trace the spiral arms of the Galaxy. Present pulsar characteristics are used to divide them into two pulsar types as defined by Huang (1987). The ages of Type II pulsars and the galactic rotation curve are used to determine their position at birth.
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Pulsars are used to trace the spiral arms of the Galaxy. Present pulsar characteristics are used to divide them into two pulsar types as defined by Huang (1987). The ages of Type II pulsars and the galactic rotation curve are used to determine their position at birth.
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Two-arm eccentric spiral antenna
IEEE Transactions on Antennas and Propagation, 1997This paper presents a free-space analysis of a planar two-arm eccentric spiral antenna. The eccentricity generates a circularly polarized wave with the main beam directed off-normal to the spiral plane. Input impedance and radiation characteristics are calculated from the current distribution generated by a method of moments solution.
R.T. Gloutak, N.G. Alexopoulous
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