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Simulation and Compensation of Measurement Errors in a Spherical Near-Field Scanner

Damberg, Klas LU (2016) EEM820 20161
Department of Biomedical Engineering
Abstract (Swedish)
Det här examensarbetet beskriver ett projekt som har genomförts med Phasor Solutions Ltd om att simulera olika fel som kan uppstå i en sfärisk närfälts skanner (SNFS). En SNFS är ett komplicerat mätsystem som gör det möjligt att göra exakta mätningar för en halvsfär runt antennen som testas. Då frekvenserna som används i skannern är höga, geometrin är komplicerad och att transformation mellan närfält och fjärrfält kräver att mätpunkterna är exakt på vissa positioner finns det en hög risk för fel i mätningarna.
Examensarbetet beskriver en metod för att simulera och verifiera de fel som har högst sannolikhet att finnas i Phasors SNFS. Från detta har det visats att radiella fel på scannern ger kraftiga fel i mätningarna och det är också... (More)
Det här examensarbetet beskriver ett projekt som har genomförts med Phasor Solutions Ltd om att simulera olika fel som kan uppstå i en sfärisk närfälts skanner (SNFS). En SNFS är ett komplicerat mätsystem som gör det möjligt att göra exakta mätningar för en halvsfär runt antennen som testas. Då frekvenserna som används i skannern är höga, geometrin är komplicerad och att transformation mellan närfält och fjärrfält kräver att mätpunkterna är exakt på vissa positioner finns det en hög risk för fel i mätningarna.
Examensarbetet beskriver en metod för att simulera och verifiera de fel som har högst sannolikhet att finnas i Phasors SNFS. Från detta har det visats att radiella fel på scannern ger kraftiga fel i mätningarna och det är också svårt att korregera för detta fel. Detta arbete har lett till att designen för Phasor’s SNFS har blivit justerad för att minimera the radiella felet. Även andra möjliga fel har simulerats och utvärderats.
Tillsammans med detta arbete så har en utökad litteratursökning genomförts kring olika metoder för att korrigera för mätfel i SNFS. Den metod som visat mest potential är en felkorrigeringsmetod utvecklad av F.D Agostino et al som bygger på lokal interpolation. Denna metod har blivit föreslagen till Phasor och en implementation av den har påbörjats. Denna metod kommer att göra det möjligt för Phasor att korrigera för Ɵ och φ fel, och kanske ännu mer viktigt, tillåta färre mätpunkter genom att enbart använda redundanta mätpositioner. (Less)
Abstract
This thesis covers the work that has been carried out with Phasor Solutions Ltd on simulating possible errors in their spherical near field scanner (SNFS). A SNFS is a scanner that enables exact measurement to be taken in a complete hemisphere around an antenna under testing (AUT). Due to the high frequency, complex geometries and the fact that the transformation between near-field and far-field demands the measurement points to be at certain position there is risk of errors.
This thesis describes and proves a method of simulating the most likely errors in Phasor’s SNFS. From this work it has been proved that a radial error in the SNFS would give a big error in the antenna far field pattern and also be difficult to correct for. This work... (More)
This thesis covers the work that has been carried out with Phasor Solutions Ltd on simulating possible errors in their spherical near field scanner (SNFS). A SNFS is a scanner that enables exact measurement to be taken in a complete hemisphere around an antenna under testing (AUT). Due to the high frequency, complex geometries and the fact that the transformation between near-field and far-field demands the measurement points to be at certain position there is risk of errors.
This thesis describes and proves a method of simulating the most likely errors in Phasor’s SNFS. From this work it has been proved that a radial error in the SNFS would give a big error in the antenna far field pattern and also be difficult to correct for. This work has led to changes in the design of the SNFS and has been able to advise the mechanical design and show that radial errors could be severe for the measurements. Different possible errors have also been tried and evaluated.
Together with this work an extended literature search has been carried out looking at different methods to correct for errors. The most promising error correction scheme has been suggested to Phasor, which is a local interpolation scheme by F.D’ Agostino et al and an implementation of this has been started together with Phasor Solutions. This would enable Phasor to correct for Ɵ and φ errors but also, and maybe more importantly, to reduce the measurement time by reducing the number of measurements points and only using the non-redundant points. (Less)
Popular Abstract
Simulation and compensation of measurement errors in a spherical near-field scanner

Spherical near field scanners (SNFS) are complex measurement systems that enable a full hemisphere radiation measurement of antennas. This thesis has successfully developed a method to simulate different errors as well as performing an in depth study in error correction methods for SNFS. This has been carried out with Phasor Solutions Ltd for the test system that will enable high accuracy antenna measurement for their low profile electronically steerable phased array antennas.
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author
Damberg, Klas LU
supervisor
organization
course
EEM820 20161
year
type
H2 - Master's Degree (Two Years)
subject
language
English
additional info
2016-09
id
8883651
date added to LUP
2016-06-21 13:00:32
date last changed
2016-06-21 13:00:32
@misc{8883651,
  abstract     = {This thesis covers the work that has been carried out with Phasor Solutions Ltd on simulating possible errors in their spherical near field scanner (SNFS). A SNFS is a scanner that enables exact measurement to be taken in a complete hemisphere around an antenna under testing (AUT). Due to the high frequency, complex geometries and the fact that the transformation between near-field and far-field demands the measurement points to be at certain position there is risk of errors.
This thesis describes and proves a method of simulating the most likely errors in Phasor’s SNFS. From this work it has been proved that a radial error in the SNFS would give a big error in the antenna far field pattern and also be difficult to correct for. This work has led to changes in the design of the SNFS and has been able to advise the mechanical design and show that radial errors could be severe for the measurements. Different possible errors have also been tried and evaluated. 
Together with this work an extended literature search has been carried out looking at different methods to correct for errors. The most promising error correction scheme has been suggested to Phasor, which is a local interpolation scheme by F.D’ Agostino et al and an implementation of this has been started together with Phasor Solutions. This would enable Phasor to correct for Ɵ and φ errors but also, and maybe more importantly, to reduce the measurement time by reducing the number of measurements points and only using the non-redundant points.},
  author       = {Damberg, Klas},
  language     = {eng},
  note         = {Student Paper},
  title        = {Simulation and Compensation of Measurement Errors in a Spherical Near-Field Scanner},
  year         = {2016},
}