Pravinkumar,P A; Dr.Nair, K G(Cochin University of Science and Technology, March 18, 1985)
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Abstract:
With the advent of satellite communication and radio astronomy, the need for large and efficient reflector antennas had triggered a widespread investigation in reflector feed design techniques. Major improvements sought are reduction in spill-over, cross polarization losses and the enhancement of aperture efficiency. The search for such a feed culminated in the corrugated horn. The main idea behind the present work is to use the H-plane sectoral horns fitted with,corrugated flanges as feeds of a paraboloid and see how the secondary pattern
of the reflector antenna varies with different parameters of the feed. An offset paraboloid is used as the secondary reflector in order to avoid the adverse effect of aperture ‘blocking by the feed horn structure on the secondary radiation pattern. The measurements were repeated for three
different H-plane sectoral horns with the same set of corrugated flanges at various X-band frequencies. The following parameters of the whole system are studied: (a) Beam shaping. (b) Gain. (c) Variation of VSWR and (d) Cross polarization
Description:
Department of Physics, Cochin University of Science and Technology
Jose,K A; Dr.Nair, K G(Cochin University of Science And Technology, July , 1989)
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Abstract:
The- classic: experiment of Heinrich Hertz verified
the theoretical predict him of Maxwell that kxnfli radio and
light waves are physical phenomena governed by the same
physical laws. This has started a.rnnJ era of interest in
interaction of electromagnetic energy with matter. The
scattering of electromagnetic waves from a target is cleverly
utilized im1 RADAR. This electronic system used tx> detect
and locate objects under unfavourable conditions or obscuration
that would render the unaided eye useless. It also
provides a means for measuring precisely the range, or distance
of an object and the speed of a moving object.
when an obstacle is illuminated by electromagnetic
waves, energy is dispersed in all directions. The dispersed
energy depends on the size, shape and composition of the
obstacle and frequency and nature of the incident wave.
This distribution of energy’ is known as ‘scattering’ and
the obstacle as ‘scatterer’ or 'target'.
Description:
Department of Electronics, Cochin University of Science And Technology