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L band

About: L band is a(n) research topic. Over the lifetime, 674 publication(s) have been published within this topic receiving 4570 citation(s).


Papers
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Proceedings ArticleDOI
04 Mar 2012
Abstract: We demonstrate 1023 Tb/s transmission over 3×80 km of PSCF by employing 548-Gb/s PDM-64QAM single-carrier frequency-division-multiplexing (SC-FDM) signals with pilot tone and 112-THz ultra-wideband low-noise amplification in the C- and extended L-bands

159 citations

Journal ArticleDOI
Abstract: Moist air is characterized for the frequency range 1–1000 GHz as a nonturbulent propagation medium described by meteorological parameters An adequate spectroscopic data base for air consists of three terms: (1) resonance information for 29 H2O lines up to 1097 GHz and 44 O2 lines up to 834 GHz in the form of intensity coefficients and center frequency for each line; (2) an empirical water vapor continuum spectrum; and (3) a liquid water attenuation term for haze and cloud conditions This data base is the heart of two computer programs which calculate and plot attenuation rates (in decibels per kilometer), refractivity (in parts per million), and refractive dispersion (in parts per million) The first covers the troposphere and requires pressure, temperature, and relative humidity as input data The second addresses isolated line behavior in the mesosphere wherein the geomagnetic field strength H is an additional input parameter due to the Zeeman effect of the O2 molecules Each oxygen line splits proportionally with H into numerous sublines, which are juxtaposed to form Zeeman patterns spread over a megahertz scale Patterns of three main polarization cases are considered Various typical examples for a model atmosphere demonstrate the utility of the approach, provide new information, and underline the serious role that water vapor plays above 120 GHz

134 citations

Journal ArticleDOI
Abstract: This paper proposes an optimization-design method for the frequency selective surface (FSS) based on the genetic algorithm (GA) incorporated with a geometry-refinement technique. The present method takes the connectivity condition of the elements into consideration, thereby resulting in an easy fabrication. As an example, we design the multiband single-layer FSS for transmitting L band (1.5 GHz band) and S band (2.5 GHz band) and also reflecting Ka band (20/30 GHz band). The designed FSS has bandwidths broader than previous FSSs. Finally, the validity of the present method is proved by the agreement between the calculated and the measured transmission responses for the designed FSS.

126 citations

Journal ArticleDOI
Abstract: Having achieved 'first-light' right before the opening ceremony on September 25, 2016, the Five-hundred-meter Aperture Spherical radio Telescope (FAST) is being busily commissioned Its innovative design requires ~1000 points to be measured and driven instead of just the two axes of motion, eg Azimuth and Elevation for most of the conventional antennae, to realize pointing and tracking We have devised a survey plan to utilized the full sensitivity of FAST, while minimizing the complexities in operation the system The 19-beam L band focal plan array will be rotated to specific angles and taking continuous data streams while the surface shape and the focal cabin stay fixed Such a survey will cover the northern sky in about 220 full days Our aim is to obtain data for pulsar search, HI (neutral hydrogen) galaxies, HI imaging, and radio transients, simultaneously, through multiple backends These data sets could be a significant contribution to all related fields in radio astronomy and remain relevant for decades

101 citations

Journal ArticleDOI
TL;DR: Field tests related to planned mobile satellite systems (MSS) were performed, and results that add to the existing database of propagation measurements at L-band (1.5 GHz) are described.
Abstract: Field tests related to planned mobile satellite systems (MSS) were performed, and results that add to the existing database of propagation measurements at L-band (1.5 GHz) are described. They are considered particularly useful in that propagation effects were studied systematically with repeated and controlled runs pertaining to different path elevation angles, road types, and path geometries defining shadowing and line-of-sight modes. In addition, simultaneous L-band and UHF measurements were performed for the purpose of establishing scaling factors applicable to previous UHF (870 MHz) results. The control of the experimental parameters was made possible by using a helicopter as the source platform and a mobile van which housed the receiver. >

92 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202134
202036
201944
201838
201741
201634