L'abstract è  presente nell'allegato / the abstract is in the attachmen

CIORBA, LORENZO

English

L'abstract è  presente nell'allegato / the abstract is in the attachmen

PORTO@iris (Publications Open Repository TOrino - Politecnico di Torino)

29 November 2022POLITECNICO DI TORINORepository ISTITUZIONALEUAV-based Far-Field and Near-Field Antenna Measurements / Ciorba, Lorenzo. - (2022 Oct 18), pp. 1-137.OriginalUAV-based Far-Field and Near-Field Antenna MeasurementsPublisher:PublishedDOI:Terms of use:Altro tipo di accessoPublisher copyright(Article begins on next page)This article is made available under terms and conditions as specified in the  corresponding bibliographic description inthe repositoryAvailability:This version is available at: 11583/2972561 since: 2022-10-24T11:28:10ZPolitecnico di TorinoAbstractUAV-based Far-field and Near-fieldAntenna MeasurementsIn recent years, Unmanned Aerial Vehicle technology has been experimented as antennameasurement solution for very large antennas that cannot be placed in an anechoicchamber or have to be characterized in-situ. The UAV already proved to be a powerfultool for Far-Field (FF) measurements, thanks to its portability, low cost, and ability toperform arbitrary paths. In the first part of this thesis, UAV-based FF measurementsof a Square Kilometre Array prototype station in VHF band are presented. One fullSKA-Low station consists of 256 digital-beam-formed dual-polarized elements randomlydistributed on a 40-m size area. This activity demonstrated the usage of the UAV toverify the large electromagnetic models of the SKA in harsh environments such as theAustralian desert.However, Near-Field (NF) strategies become necessary when the Antenna Under Test(AUT) is so large that the Fraunhofer distance is no longer compliant with flight altituderegulations (hundreds of meters). In these cases, a Near Field to Far Field (NF-FF)transformation must be used to determine the FF quantities of interest from NF data.Such technique generally requires the knowledge of both magnitude and phase of thesampled NF signal. However, in the UAV-based measurement setup, where source andreceiver are generally not connected, the measured phase is continuously drifting duringthe flight. In current literature, different solutions have been exploited in order to retrievethe correct phase information, e.g., a fiber optic link connecting the UAV to the ground orphaseless techniques. In the second part of this thesis, a known antenna (called referenceantenna) placed in the proximity of the AUT is instead used to reconstruct the phase ofthe measured NF signal. UAV-based NF measurements on a SKA-Low prototype at 175MHz are presented to demonstrate the feasibility of the approach. The UAV equippedwith a RF source is exploited as a large (40 m x 40 m) horizontal planar NF scanner.An inverse source NF-FF transformation is applied to such NF acquisitions. In this way,FF Embedded Element Patterns, array calibration coefficients and pattern are obtained.NF-FF transformed results are validated with simulations and FF measurements.The promising results suggest the usage of the presented technique in other applicationssuch as radars, base stations and satellite antenna measurements.1

UAV-based Far-Field and Near-Field Antenna Measurements

https://iris.polito.it/bitstream/11583/2972561/3/abstract_ciorba_2022_pdfA.pdf

UAV-based Far-Field and Near-Field Antenna Measurements

Abstract

Similar works

Full text

Available Versions

PORTO@iris (Publications Open Repository TOrino - Politecnico di Torino)