System residual noise reduction for non-contact passive intermodulation measurements of array antennas using multiple testers

Abstract

This letter proposes a concept of residual noise reduction when using multiple testers for non-contact passive intermodulation (PIM) measurements with near field sensing for array antennas. As described herein, the harmonic balance method and the finite difference time domain method are used for simulation. Examination is conducted for third-order PIMs in two-tone testing in the 2 GHz band. Simulation results indicate that the PIM noise which is weaker than the residual PIM of each tester becomes detectable when using the proposed method. The concept is validated further through experimentation using an equivalent array circuit in the 2 GHz band.