Keysight Technologies 11904S User's And Service Manual

Keysight Technologies 11904S User's And Service Manual Manual pdf 27 page image

Use, Maintenance, and Care of the Devices 3Keysight 11904S User’s and Service Guide 27Calibration InformationThe calibration procedure for using the Keysight 11904S adapters requires that a 2.4 mmcalibration be done using the calibration definitions of the 11904S instead of the calibrationdefinitions of the Keysight 85056A 2.4 mm calibration kit. Although response, 1-Port, and 1-Path2-Port calibrations may also be done, the following section is a general overview of a full 2-Portcalibration, as it is the most complex of the calibrations.When performing a response calibration, leave the adapters connected and do not load thecalibration definitions of this 11904S adapter set. Refer to your network analyzer documentation orembedded help for step-by-step calibration procedures and system uncertainty information.Full two-port calibration overviewThe method used to achieve calibrated 2.92 mm connector measurements involves calibratingboth 2.4 mm test ports using 2.4 mm calibration standards: opens, shorts, and loads. ForOption 001 Kits, both the low band load and sliding load are used. The test ports need not beinsertable. Then, two 2.4 mm to 2.92 mm adapters are connected back- to- back between the testports to provide the “thru” measurements. For example, if the test port connectors are both female2.4 mm connectors, a 2.4 mm male to 2.92 male adapter mated with a 2.92 mm female to 2.4 mmmale adapter can be used as the “thru”. This method provides a better transmission calibrationthan using the 2.4 mm ports as the thru.The key to this calibration method lies in the modified standard definitions. The nominal 2.4 mmopen and short circuit standard definitions are modified to account for the presence of the 2.4 mmto 2.92 mm adapters after calibration. The measurements of the 2.4 mm standard are effectivelytranslated to the ends of the adapters so that the directivity, source match, and reflection trackingerror terms are transformed to the ends of the adapters. The thru measurements made with the2.4 mm to 2.92 mm adapter pair accounts for the length and loss of the adapters that are insertedafter the 2.4 mm calibration. The load match and transmission tracking error terms are directlycharacterized at the 2.92 mm mating plane.This calibration method assumes that the adapters being used have equal length and loss, andthat they are reflectionless. The metrology-grade adapters (2.4 mm to 2.4 mm only) and the2.4 mm to 2.92 mm adapter are designed and manufactured with very tight tolerances andtherefore exhibit very similar transmission characteristics. They may be interchanged, to measurenon-insertables, without much degradation in performance. The actual return loss of the adaptershas the most impact on the effective directivity, source match, and load match of the system. The2.4 mm calibration residual errors are degraded proportionally by the return loss of the adapters. Itis approximately equal to the RSS (adapter reflection coefficient, 2.4 mm calibration residualerrors). The reflection tracking degradation is a function of the difference between the assumedloss and delay characteristics of the 2.4 mm/2.92 mm adapters and the actual transmissioncharacteristics of the adapters.For best 2.92 mm measurement accuracy, a precision 2.92 mm calibration kit, such as the KeysightN4692A Electronic Calibration Module or the Maury Microwave 8770S mechanical calibration kit,is recommended.