New in-situ calibration of diode detectors used in six-port network analyzers

The authors present a novel method of calibrating the diode detectors used in six-port network analyzers, without disconnecting the diodes. The method uses only a precision variable attenuator or a power meter with no additional directional coupler. The important feature of this method is that no actual measurement of power is required to calibrate the diode detectors for six-port operation. It is very well suited to in-situ calibration of the diode detection circuits for operation of the six-port with pulse signals when the average power detected by the power meter drops to very low levels for low duty cycles. In these cases, the precision variable attenuator method is required. Measurement results are presented