Ricerc@Sapienza

The effect of conductor surface roughness on
electro-thermally (ET) induced passive intermodulation (PIM)

products is analysed and discussed. The analytical model com-
bined with the commercial simulator SIMBEOR is used to

examine the products of ET nonlinearity, which is significantly
influenced by the surface topography of the conductor. It is
further shown that, in spite of the rise of ohmic losses with

frequency, conductor roughness may somewhat allay the ET-
PIM growth due to concurrent increase of additional heat-sinking

The physical mechanism of the experimentally observed dependence of passive intermodulation (PIM) in printed circuits on conductor surface roughness is studied. It is shown that electrothermal (ET) nonlinearity, arising due to heating of imperfect conductors by high-power carriers in a multicarrier system, is correlated with conductor surface roughness and has a unique signature. Carriers modulate the conductor resistivity, skin depth, and surface impedance which generate PIM products.