Localizing Harmonics Source On Large Conductor Based on Near-field Scanning

Unwanted harmonic signals can be generated by imperfect conductors, contacts, and non-linear magnetic materials. For example, an 860 MHz signal can generate 2580 MHz interference. Harmonic sources can be identified through direct signal injection and a near-field scan at the harmonic frequencies. This non-invasive approach can be used to scan conductive tapes or metal frames of electronic products to find harmonic sources. In this paper, we experiment with single-ended signal injection to excite a passive conductor and scan the harmonic distribution over the surface of the object by using an H-field probe. Through this approach we can initially identify the possible nonlinear sources within a millimeter range of resolution.