Residual noise identification for PIM measurement systems using variable low-PIM termination

Abstract

In this letter, we propose the variable low-PIM termination composed of a voltage-controlled IM-source, a fixed attenuator, and a linear attenuator. The design method for evaluating PIM-level of the fixed attenuator is presented in order not to limit the variable range of entire termination. It is possible to maintain low-PIM performance in spite of using active voltage-controlled IM-source, whose IM level is extremely high. This termination is used for a dynamic residual noise identification for PIM measurement systems by observing the saturation value for voltage sweep. The validity is confirmed by experiments in 2GHz band.