Marc Dirix, Stuart Gregson, October 2022
Direct far-field (DFF) testing has become the baseline test methodology for sub-6 GHz over the air (OTA) testing of the physical layer of radio access networks (RAN). However, the proliferation of mm-wave massive multiple input multiple output (Massive MIMO) antennas for 5G New Radio (NR) rollout and the use of complex waveforms for communication system testing and primary Figure of Merit (FoM) determination has necessitated the adoption of the Compact Antenna Test Range (CATR) as the preferred test solution. The CATR was initially conceived as comprising an efficient way of testing electrically large antennas at very much reduced, fixed, range lengths [1]. However, early workers quickly recognized that the reflector edge treatment and chamber wall illumination are significant factors determining the quality and purity of the collimated pseudo plane-wave with this becoming especially important at mm-wave frequencies [3]. Using modern powerful digital computational simulation techniques [2] in combination with genetic optimization, the edge treatment can be evolved for a specific CATR application as part of the design process for a range of reflector edge treatments [3, 4]. This paper extends the authors previous work to present a novel approach for the reflector edge treatments than have hitherto been considered within the design and genetic optimization procedure, while also taking into account both wall illumination and direct quiet-zone illumination. Resulting quiet-zone performances are compared and contrasted.
[1] C.G. Parini, S.F. Gregson, J. McCormick, D. Janse van Rensburg “Theory and Practice of Modern Antenna Range Measurements”, IET Press, 2014, ISBN 978-1-84919-560-7.
[2] S.F. Gregson, C.G. Parini, “Examination of the Effect of Common CATR Quiet Zone Specifications on Antenna Pattern Measurement Uncertainties”, Loughborough Conference on Antennas and Propagation, Loughborough, November 2017.
[3] M. Dirix, S.F. Gregson, “Optimisation of the Serration Outline Shape of a Single Offset-Fed Compact Antenna Test Range Reflector Using A Genetic Evolution of the Superformula”, EuCAP virtual conference, March 22-26 2021.
[4] M. Dirix, S. Gregson and R. Dubrovka, “Genetic Evolution of the Reflector Edge Treatment of a Single Offset-Fed Compact Antenna Test Range for 5G New Radio Applications,” in AMTA Annual Meeting and Symposium, Daytona Beach, Florida, 2021