A transformation procedure directly computing the antenna far-field pattern from near-field samples acquired on a planar spiral is proposed in this paper. The convolution property of the radiation integral is exploited to efficiently perform the evaluation by taking advantages of the Fast Fourier Transform, without the need of any intermediate interpolation process. Validations on circular arrays of elementary dipoles are presented to show the effectiveness of the method.
2. Williams, L. I., Y. Rahmat-Samii, and R. G. Yaccarino, "The bi-polar planar near-field measurement technique, Part I: Implementation and measurement comparison," IEEE Trans. Antennas Propag., Vol. 42, No. 2, 184-195, 1994.
doi:10.1109/8.277212
3. Yaccarino, R. G., L., I. Williams, and Y. Rahmat-Samii, "Linear spiral sampling for the bipolar planar near-field antenna measurement technique," IEEE Trans. Antennas Propag., Vol. 44, No. 7, 1049-1051, 1996.
doi:10.1109/8.504314
4. Bucci, O. M., C. Gennarelli, and C. Savarese, "Fast and accurate near-field far-field transformation by sampling interpolation of plane-polar measurements," IEEE Trans. Antennas Propag., Vol. 39, No. 1, 48-55, 1991.
doi:10.1109/8.64434
5. D'Agostino F., C. Gennarelli, and G. Riccio, "Theoretical foundations of near-field far-field transformations with spiral scannings," Progress In Electromagnetics Research, Vol. 61, 193-214, 2006.
doi:10.2528/PIER06021401
6. D'Agostino, F., F. Ferrara, C. Gennarelli, and G. Riccio, "Directivity computation by spherical spiral scanning in near field region," Journal of Electromagnetic Waves and Applications, Vol. 19, No. 10, 1343-1358, 2005.
doi:10.1163/156939305775525927
7. Costanzo, S. and G. Di Massa, "Direct far-field computation from bi-polar near-field samples," Journal of Electromagnetic Waves and Applications, Vol. 20, No. 9, 1137-1148, 2006.
doi:10.1163/156939306777442926
8. Weaver, H. J., Theory of Discrete and Continuous Fourier Analysis, John Wiley and Sons, New York, 1989.
9. Costanzo, S. and G. Di Massa, "Far-field reconstruction from phaseless near-field data on a cylindrical helix," Journal of Electromagnetic Waves and Applications, Vol. 18, No. 8, 1057-1071, 2004.
doi:10.1163/1569393042955414