Propagation research in Europe using the OLYMPUS satellite
Article Abstract:
The OLYMPUS propagation project underway in Europe is intended to develop, launch, and operate a multipurpose satellite for diverse telecommunications applications, as well as to develop a series of telecommunications payloads. The three modules comprising the spacecraft body are the propulsion module, the service module, and the communication module; each is described. OLYMPUS was launched from an Ariane facility in French Guyana in July 1989; problems encountered in orbit have reduced the expected mission lifetime to slightly less than the five years planned. The four payloads carried by OLYMPUS are a multibeam 12/14-GHz communications payload for experiments with specialized services; a direct broadcast payload for direct broadcast satellite experiments at 11 GHz; a 20/30-GHz communications payload for business services, videoconferencing, and other such applications; and a propagation package.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1993
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Pulse propagation in a linear, causally dispersive medium
Article Abstract:
An overview of an analysis of linear dispersive pulse propagation in a Lorentz medium that uses modern asymptotic techniques gives an accurate description of the whole dynamical field evolution. Contrary to previously held beliefs that the amplitude of the precursor fields have small significance compared to the signal's amplitude, either of the Sommerfield or Brillouin precursor fields dominates the structure of the propagated field. Pulse distortion is due mainly to the mature dispersion regime's precursor fields. Signal velocity is seen either as not useful or as in disagreement with experimental observations because of the ambiguity in physically measuring the exact point at which a transition is made in field evolution. But with a physically realizable, causally dispersive medium, these objections become baseless.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1991
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Ray methods for modal fields in general closed and open propagation environments
Article Abstract:
True plane waves, local plane waves and their ray schema are defined so that a mode field synthesis for ideal modes and then adiabatic modes (AM) can be compared with exact solutions to assess the quality and limitations of formulations when juxtaposed with intrinsic modes that remove AM deficiencies in cutoff regions. Sensing, communications and other applications that require efficient and spatially confined transfer of information need electromagnetic and other waves to be guided. When guiding channels are man-made, they can be controlled. Mode fields are of central importance in analytic modeling of guided propagation. A well-defined modal field is traced through a continuously refracting medium that changes from being guiding to antiguiding. This transforms the trapped mode into a radiated beam.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1991
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- Abstracts: Differential absorption lidar sensing of ozone. Lidar sensing of aerosols and clouds in the troposphere and stratosphere
- Abstracts: A review of specification and verification methods for parallel programs, including the dataflow approach. A language for compositional specification and verification of finite state hardware controllers