Yoshihide YAMADA, Rezwanul AHSAN, Norbahiah MISRAN, Mohammad Tariqul ISLAM

Ray tracing technique for shaping a dual reflector antenna system

In radio astronomy applications, antennas having the highest aperture efficiencies are requested. In order to meet this request, a reflector shaping program for dual reflector antennas has been developed. The design procedure is based on the geometrical optics where differential equations have been formulated to define the ray trace of the antenna system. Recently, the fourth generation programming language MATLAB has become well known for its numerical computing environment and very useful three-dimensional data visualization functions. The authors wished to make a dual reflector shaping program by a ray tracing method in MATLAB. In this paper, details of the program are explained, and antenna ray tracing results are shown visually by three-dimensional viewgraphs. The numerical results are compared with the theoretical ones to confirm the correctness of the developed shaping program for a Cassegrain dual reflector antenna system. For uniform aperture distribution the first side lobe level is numerically obtained as 17.59 dB, which can be further reduced through shaping to 24.67 dB and 30.65 dB for parabolic and squared parabolic, respectively.

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[1] Sletten CJ. Reflector and Lens Antennas: Analysis and Design Using Personal Computers. 1st ed. Norwood, MA, USA: Artech House, 1988.
[2] Galindo V. Design of dual-reflector antennas with arbitrary phase and amplitude distributions. IEEE T Antennas Propag 1964; 12: 403-408.
[3] Collins GW. Shaping of subreflectors in Cassegrain antennas for maximum aperture efficiency. IEEE T Antennas Propag 1973; 21: 309-313.
[4] Williams WF. High efficiency antenna reflector. Microw J 1965; 8: 79-82.
[5] Baker L. Reflector shaping by optimization of wavefront shapes. In: International Symposium on Antennas and Propagation Society; 2428 June 1991; Ontario, Canada: IEEE. pp. 172-174.
[6] Kinber BY. On two-reflector antennas. Radio Eng Electron Phys 1962; 6: 914-921.
[7] Moreira FJS, Prata Jr. A, Bergmann JR. GO shaping of omnidirectional dual-reflector antennas for maximum gain. In: SBMO/IEEE MTT-S International Conference on Microwave and Optoelectronics; 2528 July 2005; Brasilia,Brazil: IEEE. pp. 665-668.
[8] Kildal PS. Synthesis of multireflector antennas by kinematic and dynamic ray tracing. IEEE T Antennas Propag 1990; 38: 1587-1599.
[9] Kim Y, Lee TH. A new shaping method for circularly symmetric dual reflector antennas. In: IEEE International Symposium on Antennas and Propagation Society; 38 July 2005; Washington, USA: IEEE. pp. 470-473.
[10] Moreira FJS, Jose RB. Shaping axis-symmetric dual-reflector antennas by combining conic sections. IEEE T Antennas Propag 2011; 59: 1042-1046.
[11] Lo YT, Lee SW. Antenna Handbook: Antenna Theory, 1st ed. Berlin, Germany: Springer-Verlag, 1993.
[12] Stutzman WL, Thiele GA. Antenna Theory and Design, 3rd ed. Hoboken, NJ, USA: John Wiley & Sons, 2012.
[13] Balanis CA. Modern Antenna Handbook. Hoboken, NJ, USA: John Wiley & Sons, 2011.
[14] Lee J, Parad L, Chu R. A shaped offset-fed dual-reflector antenna. IEEE T Antennas Propag 1979; 27: 165-171.