A quasi-optical (QO) free-space test bench, based on two dual reflector Compact Test Range (CTR) systems, has been developed to characterise the RF properties of materials and QO components used in mm-wave astronomical instrumentation. While this facility has been designed to operate for several spectral bandwidths, in the first instance measurements have been performed in the W-band (75-110 GHz). We present the modelled and measured performance of the test bench and the procedure for calibrating and measuring samples under test. First measured results of the field across a 10 cm quiet zone indicate a maximum intensity variation of -4.5 dB and a maximum phase variation of 7°. Measurements of the cross-polarisation indicate higher levels than were predicted. A free-space calibration method has been developed based on the use of 3 calibration standards (Thru-Reflect-Line). Initial measurements of the reflectivity and transmittance for a range of materials have been performed, allowing the deduction of the refractive index.
Implementation of a Quasi-Optical Free-Space S-Parameters Measurements System / Maffei, B.; Legg, S.; Robinson, M.; Ozturk, F.; Ng, M. W.; Schemmel, P.; Pisano, G.. - (2013). (Intervento presentato al convegno 35th ESA Workshop on Antenna and Free Space RF Measurements tenutosi a ESTEC - Noordwijk, The Netherlands).
Implementation of a Quasi-Optical Free-Space S-Parameters Measurements System
G. Pisano
2013
Abstract
A quasi-optical (QO) free-space test bench, based on two dual reflector Compact Test Range (CTR) systems, has been developed to characterise the RF properties of materials and QO components used in mm-wave astronomical instrumentation. While this facility has been designed to operate for several spectral bandwidths, in the first instance measurements have been performed in the W-band (75-110 GHz). We present the modelled and measured performance of the test bench and the procedure for calibrating and measuring samples under test. First measured results of the field across a 10 cm quiet zone indicate a maximum intensity variation of -4.5 dB and a maximum phase variation of 7°. Measurements of the cross-polarisation indicate higher levels than were predicted. A free-space calibration method has been developed based on the use of 3 calibration standards (Thru-Reflect-Line). Initial measurements of the reflectivity and transmittance for a range of materials have been performed, allowing the deduction of the refractive index.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
