MW non-linear junction detector (NLJD) is used for search and location of electronic devices both in active and switch-off state.
The detector operation is based on the property of semiconductor components to generate a response at the 2d and 3d harmonics when radiated by a microwave probing signal.
Semiconductor components of artificial origin will have a higher level second harmonic while semiconductor components of natural origin (e.g. oxide films) will have a higher level third harmonic respectively.
