Near-field measurement of an offset reflector antenna at a spherical range in anechoic chamber

This dataset corresponds to the near field (NF) measurements of a 70 cm diameter offset reflector antenna, fed with a circularly polarized helix antenna, working at 4650 MHz [1,2].The reflector antenna was measured at the spherical range in an anechoic chamber of the University of Oviedo, in Spain. This anechoic chamber has a roll over azimuth positioner that enables full spherical acquisions. Two different measurement distances were considered, R1 = 3.198 m and R2 = 5.191 m. Samples on both spherical acquisition surfaces were taken according to a sampling rate of 1 degree in theta (or azimuth axis), and 3 degrees in phi (roll axis). The two tangential components of the electric field (Eth, Eph) were measured.This dataset can be used for testing near-field-to-far-field (NF-FF) transformation techniques [3]. Besides, measurements are provided at two different distances, thus enabling the assessment of amplitude-only antenna diagnostics and NF-FF transformation methods [4-7].[1] García Fernández, M.; Álvarez López, Y.; Las-Heras, F. Dual-Probe Near-Field Phaseless Antenna Measurement System on Board a UAV. Sensors 2019, 19, 4663.[2] M. G. Fernández, Y. Álvarez López and F. L. -H. Andrés, Advances in Antenna Measurement and Characterization Using Unmanned Aerial Vehicles, 2019 13th European Conference on Antennas and Propagation (EuCAP), Krakow, Poland, 2019, pp. 1-5.[3] Y. Alvarez, F. Las-Heras and M. R. Pino, Reconstruction of Equivalent Currents Distribution Over Arbitrary Three-Dimensional Surfaces Based on Integral Equation Algorithms, in IEEE Transactions on Antennas and Propagation, vol. 55, no. 12, pp. 3460-3468, Dec. 2007,[4] C. Cappellin, A. Frandsen and O. Breinbjerg, Application of the SWE-to-PWE antenna diagnostics technique to an offset reflector antenna, IEEE Antennas Propag. Mag., vol. 50, no. 5, pp. 204-213, Oct. 2008.[5] Y. Alvarez, F. Las-Heras, and M. R. Pino, “The sources reconstruction method for amplitude-only field measurements,” IEEE Transactions on Antennas and Propagation, vol. 58, no. 8, pp. 2776–2781, 2010.[6] Zhi-Xiang Xie, Yun-Hua Zhang, Si-Yuan He, Guo-Qiang Zhu, A Novel Method for Source Reconstruction Based on Spherical Wave Expansion and NF-FF Transformation Using Amplitude-Only Data, IEEE Transactions on Antennas and Propagation, vol.67, no.7, pp.4756-4767, 2019.[7] Fernando Rodríguez Varela, Javier Fernandez Álvarez, Belén Galocha Iragüen, Manuel Sierra Castañer, Olav Breinbjerg, Numerical and Experimental Investigation of Phaseless Spherical Near-Field Antenna Measurements, IEEE Transactions on Antennas and Propagation, vol.69, no.12, pp.8830-8841, 2021.