Analysis of Feeding Systems for
Double Reflector Spherical Antennas
A.Sargsyan1,2, H.Abrahamyan1,2, Y.Alkhatib1 , G.Hakobyan1
1 State Engineering University of Armenia2 National Institute of Metrology
IRPhE-2012, October 17, 2012, Yerevan
Outline
• Introduction
• Different types of antennas suitable as a main
feed
• Antenna arrays as feeds for correcting reflector
• Supplementary Linear Feed (SLF) for ROT-
54/2.6
• Conclusion
Introduction
• Application of Double Reflector antennas: in Radio
astronomy, as well as in Deep Space Communication
for microwave ranges of wavelengths
• double reflector-systems of Cassegrain and Gregory
• crucial are: the weight, hardness of the constructing
materials, costs, etc.
• due to the deformation of materials, movement
deformations, etc
• large spherical double reflector antennas
with unmovable main spherical mirror and
mobile correcting mirror
• Prof. Paris Herouni, the end of 50-th of last
century
Radio-optical telescope ROT - 54/2,6
• was completed during 1985-87 and placed
on Aragats mountain (National Institute of
Metrology, Orgov)
Single antenna feeds
___ - conical horn,
------ - open- end waveguide
-..-..-..- - open- end waveguide
with Teflon sleeve
and vibrator.
-.-.-.- - pyramidal corrugated horn
Double reflector spherical antenna
(DSA)’s feeding system
• optimal feeding of the secondary
correcting reflector is possible by using
different types of single feeds
Antenna arrays as feeds for
correcting reflector
a) horizontal surface b) vertical surface
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
smooth spheric cone
1
F
-10º -5º 5º 10
º
º
Antenna arrays as feeds for
correcting reflector
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
smooth spheric cone 1
F
-10º -5º 5º 10
º
º
is able to move in space ~ 18.75 min of arc
the maintenance of the radiation
optimal condition of ROT- 54/2.6
antenna feed is received when the
distance between SWA parts
constitutes 25mm
Supplementary Linear Feed (SLF) for
ROT-54/2.6
SUF can be improved up to 0.707R0
That made the SUF increase by 17.8%.
Conclusion
• Double Reflector Spherical Antennas have
a couple of considerable advantages
against parabolic antennas.
• In order to enjoy these advantages
possibly, suitable feeding system should
be applied.
Thank you for your attention