An optimised calibration method of six-port reflectometer

A developed calibration method of six-port junction is proposed, in which a dual-tone technique is used to produce multi-samples and more accurate results are achieved by use of the least-square method and excluding those samples which may cause bigger errors. A 0.9 ~5 GHz MIC six-port reflectometer was constructed and the Engen´s robust calibration procedure was used for comparison. Eight test samples were used in the measurement. For Engen´s calibration procedure, the difference between the HP8510 and the six port reflectrometer is in the order of 0.3 dB/1.6deg for most cases, but at the boundary frequencies the biggest differences are 0.65 dB/2.6deg; while this method give the difference range between the HP8510 is less than 0.1 dB/1deg for most cases and a biggest error of 0.35 dB/1.7deg for boundary frequencies. This method can apparently increase the measure accuracy especially at the boundary frequencies of six-port junction.