Reverse-PIM extraction in non-contact antenna-PIM measurement

In this paper, we propose an extraction method of the reverse-PIM component of the direct measurement from the non-contact measurement. To compensate the frequency-dependent mutual coupling between employed antennas, each transmission power is set so that the sample antenna be excited balance for the transmitting frequencies. Under the above condition, a FDTD simulation is carried out to analyze the influence of non-contact excitation on the antenna-current distribution. It is found that the direct excitation causes extra current flow along the feeding line and leads to conversion error. That is also confirmed through the fact that such error can be compensated by the placement angle of the IM-source diode in the sample antenna.