A new approach to the direct observation of third-

order passive intermodulation (PIM3) products on the microstrip

transmission lines is proposed. Mapping of PIM3 product

distributions along printed microstrip traces and nearby

localised sources has been realised with the aid of the near field

probing and a standard PIM analyser. The results of PIM3

measurements are presented and discussed in comparison with

simulations based on a nonlinear transmission line model (NTL)

as well as earlier experimental studies.