Author
L. Shafai
Bio: L. Shafai is an academic researcher. The author has contributed to research in topics: Slot antenna & Reconfigurable antenna. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.
Papers
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25 Jun 1984
4 citations
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TL;DR: In this paper, a multiband antenna system supporting multiple communication services and multiple beams is presented, where the smooth-walled horn has efficient radiation patterns over three frequency bands that are spread over an octave bandwidth and provides optimal illumination on the reflector at all the frequency bands.
Abstract: A multiband antenna system supporting multiple communication services and multiple beams is presented. Key component of the antenna is the smooth-walled horn that has efficient radiation patterns over three frequency bands that are spread over an octave bandwidth and provides optimal illumination on the reflector at all the frequency bands. Results of the feed horn and the antenna are discussed.
19 citations
03 Jul 2005
TL;DR: In this article, the authors investigated the performance of multimode feed horns with reflector assembly for radar systems, where ground moving target indicator (GMTI) mode implementation is desired. But the results of the investigation were limited.
Abstract: The investigation results of multimode feed horns are presented, which provide multi-phase centre radiation performance with the reflector. These feed horns with reflector assembly are suitable for radar systems, where ground moving target indicator (GMTI) mode implementation is desired. The simulations were carried out using Ansoft Corporation's HFSS v8.5 for feed horn, and Ticra's GRASP v7.0 for the reflector.
14 citations
TL;DR: In this article, an algorithm to measure the phase center position of an antenna in an Anechoic Chamber (AC) is presented. But it is based on the assumption that the PhC belongs to the geometrical symmetry axis of the antenna under test.
Abstract: An algorithm to measure in Anechoic Chamber (AC) the antenna Phase Center (PhC) position is presented. It is based on the assumption that the PhC belongs to the geometrical symmetry axis of the antenna under test. In particular, the algorithm is able to account for the possible presence of an unknown misalignment between such axis and the rotation axis of the turntable of the AC, thus extending the two point-approach available in the literature. The method has been validated through measurements on an X-band microstrip radar antenna.
9 citations
01 Jul 2004
TL;DR: The phase center of a feed horn is a theoretical point along the axis of the horn which is the centre of curvature of the phase fronts of the spherical waves as discussed by the authors. But in most feeds, there is a phase centre region rather than a single point because radiation is due to a summation of spherical waves, which seems to emanate from the aperture.
Abstract: The phase centre of a feed horn is a theoretical point along the axis of the horn which is the centre of curvature of the phase fronts of the spherical waves. In most feeds, there is a phase centre region rather than a single point because radiation is due to a summation of spherical waves, which seems to emanate from the aperture [1]. Determination of the feed phase centre helps, its location relative to the focal point of the reflector. Different techniques to compute and determine the phase centre location in single and dual reflector geometries are reported in [1-3]. However, when the feed horn has a multimode excitation, the amplitude and phase control of modes provide different constant phase centre locations, which in turn helps to conceptualize a virtual array on the reflector antenna aperture [4].
8 citations