CAT-7 cable evaluation for Square Kilometre Array analogue signal transport
SAIEE Africa Research Journal
Department of Electrical anil Electronic Engineering, University of Stellenbosch, 7600 Stellenbosch, South Africa; Jodrell Bank Observatory, University of Manchester, Macclesfield, Cheshire, United Kingdom
Data-cable systems are essential for an evolving Square Kilometre Array (SKA) phased array demonstrator project. Loss, dispersion and channel coupling are the characteristics of interest. We evaluate a Category 7 (CAT-7) cable system, which incorporates a 20 m CAT-7 cable, balun transformers, and ARJ45 connectors. Measurements from 30 MHz - 1.5 GHz are made using a calibrated Vector Network Analyzer (VNA). Through, Reflect, Line (TRL) as well as Short, Open, matched Load, Through (SOLT) calibration techniques were performed, which separately test the cables and the entire system performance respectively. A further measurement isolates the baluns. The connectors and baluns are mounted on customised printed circuit boards. We investigated phase dispersion, return loss, attenuation, near-end crosstalk (NEXT) and far-end crosstalk (FEXT). The best system was found to have a linear phase response in the 30 MHz to 1.4 GHz band, with NEXT and FEXT levels below -50 dB and -63 dB respectively. Such performance makes this cable class a candidale lor high-volume dala streams anlicipaled lor Ihe SKA.
Baluns; CAT-7 cables; Connectors; EMC; Far end crosstalk; Near end cross talks; Square Kilometre Array; Calibration; Crosstalk; Dispersions; Electric network analysis; Electric network analyzers; Electronic equipment manufacture; Microstrip devices; Printed circuit boards; Cables