BUSCADOR RECOLECTA

This article presents a portable system for freehand antenna diagnosis and characterization based on amplitude-only data. The amplitude-only samples are acquired by moving a handheld probe, which is tracked by a motion capture system, in front of the antenna under test (AUT) aperture. The acquired measurements are processed using the phaseless sources reconstruction method to compute an equivalent current distribution on the AUT aperture. Finally, the radiation pattern of the AUT can be obtained by evaluating the corresponding radiation integrals. Unlike previous work, the use of amplitude-only data avoids the need of a phase reference, paving the way to the diagnosis and characterization of antennas under operational conditions. This fact, together with the handheld capabilities, makes the system very convenient for measurements of already deployed and onboard antennas. Moreover, these amplitude-only acquisitions also simplify the required hardware. The system has been validated through measurements in a wide frequency range from Ka-band up to 300 GHz. Despite that one cannot expect the same degree of accuracy that can be achieved under laboratory conditions (including an anechoic environment and highly accurate positioners), the system shows excellent capabilities to detect malfunctions, such as wrong amplitude/phase distributions, as well as a fair estimation of the far field., This work was supported in part by the Ministerio de Ciencia, Innovacion y Universidades of Spain/Fondo Europeo de Desarrollo Regional (FEDER) under Project RTI2018-095825-B-I00, in part by the Gobierno del Principado de Asturias under Project GRUPIN-IDI2018-000191, and in part by the Ministerio de Educacion y Formacion Profesional of Spain under Grant FPU15/06431.

This work has been funded by the Ministry of Defence - Government of Spain and by the University of Oviedo under Contract 2019/SP03390102/00000204/CN-19-002 (“SAFEDRONE”); by the Ministerio de Ciencia, Innovación y Universidades of Spain/FEDER under project RTI2018-095825-B-I00 (“Millihand”) and project PID2021-122697OB-I00; by the Ministry of Universities of Spain and European Union - NextGenerationEU - under grants MU-21-UP2021-030-53519863 and MU-21-UP2021-030-71667225; and by Gobierno del Principado de Asturias/FEDER under grant AYUD/2021/51706.