Transmission line gurus and people who love dielectrics-- I am trying to figure out the conductivity of a dielectric. I have an equation that gives me: tanD = 1/(2*pi*Freq*Er*rd) where rd is the resistivity of the dielectric I assume that 1/rd is the conductivity of the dielectric. Is that an erroneous assumption? That gives me the equation: conductivity of dielectric = 2*pi*Freq*Er*tanD This second equation makes sense to me in that increasing your frequency increases the dielectric conductivity, causing more "leakage" of your transmitted energy. However, using this equation, that would indicate that the conductivity of a dielectric with Er=4 and tanD=0.02 would have a conductivity approaching that of copper at 100MHz. Now that does not make sense. Is there a such thing as non-frequency-dependent conductivity of a dielectric? How would I obtain such a number? Is there something else I am missing? Any guidance would be greatly appreciated. Thanks. --Pat ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu