Freehand System for Antenna Diagnosis Based on Amplitude-Only Data

• Published in: IEEE transactions on antennas and propagation Vol. 69; no. 8; pp. 4988 - 4998
• Main Authors: Alvarez-Narciandi, Guillermo, Laviada, Jaime, Alvarez-Lopez, Yuri, Ducournau, Guillaume, Luxey, Cyril, Belem-Goncalves, Cybelle, Gianesello, Frederic, Nachabe, Nour, Rio, Carlos Del, Las-Heras, Fernando
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Amplitude-only; Amplitudes; antenna diagnosis; Antenna measurements; Antennas; Apertures; Current distribution; Diagnosis; Engineering Sciences; equivalent currents; Far fields; freehand; Frequency measurement; Frequency ranges; Hardware; Malfunctions; millimeter-wave (mm-wave) antenna; Motion capture; Phase measurement; phaseless; power-meter; Probes; Radiation; sources reconstruction method; millimeter-wave (mm-wave) antenna; phaseless; antenna diagnosis; equivalent currents; sources reconstruction method; Amplitude-only; antenna measurements; freehand; power-meter
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2021.3060082

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 <inline-formula> <tex-math notation="LaTeX">Ka </tex-math></inline-formula>-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.