Zachariah,E J; Dr.Nair, K G(Cochin University of Science And Technology, August , 1981)
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Abstract:
The need for improved feed systems for large reflector antennas employed in Radio Astronomy and Satellite tracking spurred the interest in horn antenna research in
the 1960's. The major requirements were to reduce spill over, cross-polarisation losses,and to enhance the aperture efficiency to the order of about 75-8O%L The search for such a feed culminated in the corrugated horn. The corrugat1e 1 horn triggered widespread interest and enthusiasm, and a large amount of work(32’34’49’5O’52’53’58’65’75’79)has already been done on this type of antennas. The properties of corrugated surfaces has been investigated in detail.
It was strongly felt that the flange technique and the use of corrugated surfaces could be merged together to obtain the advantages of both. This is the idea behind the present work. Corrugations are made on the surface of flange elements. The effect of various corrugation parameters are studied. By varying the flange parameters, a good amount of data is collected and analysed to ascertain the effects of corrugated flanges. The measurements are repeated at various frequencies, in the X— and S-bands. The following parameters of the system were studied: (a) beam shaping (b) gain (c) variation of V.S.U.R. (d) possibility of obtaining circularly polarised
radiation from the flanged horn. A theoretical explanation to the effects of corrugated flanges
is attempted on the basis of the line-source theory. Even though this theory utilises a simplified model for the calculation of radiation patterns, fairly good agreement between the computed pattern and experimental results are observed.
Description:
Department of physics, Cochin University of Science And Technology
Vasudevan, K; Dr.Nair, K G(Cochin University of Science and Technology, April 19, 1982)
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Abstract:
Antennas play an important role in determining
the characteristics of any electronic system which depends
on free space as the propagation medium. Basically, an
antenna can be considered as the connecting link between
free space and the transmitter or receiver. For radar and
navigational purposes the directional properties of an
antenna is its most basic requirement as it determines the
distribution of radiated energy. Hence the study of directional properties of antennas has got special significance
and several useful applications.
Description:
Department of Physics, Cochin University of Science and Technology
Supriyo,Dey; Aanandan,C K; Mohanan, P; K G Nair(Microwave and Optical Technology Letters, September , 1994)
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Abstract:
A simple technique to improve the impedance bandwidth of a circular
microstrip patch antenna using two sectorial slots is proposed. Using this
design more than 5% impedance bandwidth is obtained. The added
advantage of this new antenna is that it can be fed by a 50- microstrip line
Aanandan,C K; Mohanan, P; Supriyo,Dey; K G Nair(Department of Electronics, 1994)
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Abstract:
A simple technique to improve the impedance bandwidth of a circular
microstrip patch antenna using two sectorial slots is proposed. Using this
design more than 5% impedance bandwidth is obtained. The added
advantage of this new antenna is that it can be fed by a 50 microstrip
line.