Distorted Reflector Antennas: Radiation Pattern Sensitivity to the Surface Distortions

Document Type : Research Article


Department of Electrical Engineering, Amirkabir University of Technology, Tehran, Iran


The high-frequency performance of the reflector antennas is mainly limited by the surface. It has been shown that distortions on different regions of the reflector surface can have different effects on the radiation performance. In other words, degradation of the radiation pattern due to the presence of surface distortions is sensitive to the location and behavior of the surface distortion profile. In this paper, the concept of “sensitivity of the radiation pattern to the surface distortion” has been introduced and quantified. It can be used in the design of different reflector antennas to prevent radiation degradations due to surface distortion. Based on the Physical Optics and variational analysis, the first-order variational of the far-fields with respect to the surface profile is formulated to present the concept of sensitivity. The variational amplitude can be modified to show the concept of sensitivity of the radiation pattern to the distortions on the surface. Reflector antennas with different geometries and feeding methods have different sensitivity plots. Both co- and cross-polarization fields for feed antenna are considered ti be used in the symmetric and offset reflectors, and sensitivity plots are extracted. Sensitivity plots show areas on the surface that have stronger effects on the radiation pattern variations in the region of the main-lobe and the first few side-lobes.


Main Subjects

[1] S.K. Sharma, S. Rao, L. Shafai, Handbook of reflector antennas and feed systems volume I: theory and design of reflectors, Artech House, 2013.
[2] G. Cortes-Medellin, P.F. Goldsmith, Analysis of active surface reflector antenna for a large millimeter wave radio telescope, IEEE transactions on antennas and propagation, 42(2) (1994) 176-183.
[3] Y. Rahmat-Samii, Effects of deterministic surface distortions on reflector antenna performance, in: Annales des télécommunications, Springer, 1985, pp. 350-360.
[4] K. Bahadori, Y. Rahmat-Samii, Characterization of effects of periodic and aperiodic surface distortions on membrane reflector antennas, IEEE transactions on antennas and propagation, 53(9) (2005) 2782-2791.
[5] J. Ruze, Antenna tolerance theory—A review, Proceedings of the IEEE, 54(4) (1966) 633-640.
[6] J. Jervase, S. Ghobrial, Axial cross polarization in reflector antennas with surface errors of large correlation diameter, IEEE transactions on antennas and propagation, 31(4) (1983) 662-665.
[7] P. Lian, B. Duan, W. Wang, B. Xiang, N. Hu, Effects of nonuniform surface errors along the radius on reflector’s radiation characteristic and its quality evaluation, IEEE Transactions on Antennas and Propagation, 63(5) (2015) 2312-2316.
[8] P. Rocca, N. Anselmi, A. Massa, Interval arithmetic for pattern tolerance analysis of parabolic reflectors, IEEE Transactions on Antennas and Propagation, 62(10) (2014) 4952-4960.
[9] W.T. Smith, R.J. Bastian, An approximation of the radiation integral for distorted reflector antennas using surface-error decomposition, IEEE Transactions on Antennas and Propagation, 45(1) (1997) 5-10.
[10] D.-W. Duan, Y. Rahmat-Samii, A generalized diffraction synthesis technique for high performance reflector antennas, IEEE Transactions on Antennas and Propagation, 43(1) (1995) 27-40.
[11] S. Zhang, B. Duan, H. Bao, P. Lian, Sensitivity analysis of reflector antennas and its application on shaped geo-truss unfurlable antennas, IEEE Transactions on Antennas and propagation, 61(11) (2013) 5402-5407.
[12] J.A. Martinez.Lorenzo, C.M. Rappaport, A.G. Pino, Reflector antenna distortion determination: An iterative.field.matrix solution, Radio Science, 43(4) (2008).
[13] B. Westcott, A. Zaporozhets, Dual-reflector synthesis based on analytical gradient-iteration procedures, IEE Proceedings-Microwaves, Antennas and Propagation, 142(2) (1995) 129-135.
[14] A. Haddadi, A. Ghorbani, Distorted reflector antennas: analysis of radiation pattern and polarization performance, IEEE Transactions on Antennas and Propagation, 64(10) (2016) 4159-4167.
[15] A. Haddadi, P. Taghikhani, A. Ghorbani, A Variational Approach for Modeling Reflector Antenna Surface Distortions Based on Physical Optics Approximation, Antennas and RF Sysems for Space Science, 36th ESA Antenna Workshop on, the Neatherlands, 2015.
[16] P.-S. Kildal, Foundations of antenna engineering: a unified approach for line-of-sight and multipath, Artech House, 2015.
[17] K.W. Cassel, Variational methods with applications in science and engineering, Cambridge University Press, 2013.