In this letter, we describe the design for the variable low-PIM termination composed of the 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.

A non-contact passive intermodulation distortion (PIM) measurement method for antenna using high-level IM standard (HIMS) is described as proposed herein. A novel method to estimate coupling loss between sensing antenna and a sample antenna is proposed, after which a complete one-port non-contact measurement for antenna is realized. Measurements are conducted in three stages: measuring IM characteristics of HIMS, estimating coupling loss using HIMS, and estimating practical PIM level of a sample antenna. A high-level IM standard consisting of a Schottky barrier diode was used for this study. The method enables ready evaluation of practical PIM of a sample antenna from a complete one-port non-contact measurement with excellent stability and repeatability. Then the validity of the proposed method was confirmed experimentally using a printed dipole antenna. After presenting an applicable measurement method for array antenna incorporating the proposed method, its effectiveness was verified experimentally.