Rdc/Rrf Metal Model

The Rdc/Rrf planar metal loss model is used for compatibility with previous Sonnet releases. This method allows you to enter two values: RDC and RRF. The first parameter, RDC, determines loss at low frequency (where the conductor is much thinner than the skin depth). Surprisingly, other electromagnetic analyses often predict zero loss at low frequency because they assume RDC is zero.

The second parameter is the skin effect coefficient, RRF. Em multiplies this number by the square root of the frequency (in Hertz) to yield the surface resistance at high frequency. At intermediate frequencies, an equation for the surface impedance is used to provide a smooth transition from DC to high frequency.

This entry is the equivalent of the General metal model, when the DC reactance (Xdc) and the surface inductance (Ls) are zero.

For a discussion of these values, the equations used to determine them and their use in modeling loss, see the Planar Metalization Loss in the Sonnet User's Guide.