"Jeff Liebermann"
"Phil Allison"

That link shows ESR curves with frequency of a couple of * CERAMIC *
capacitors of unusually high values.

Oops, y'er right. Sorry(tm).

Oddly, while the ESR of the ceramic caps are much lower than
electrolytics, the curve shapes seem to be similar.

Googling, I find:
http://www.low-esr.com/esrfreqperfcurves.asp
Note the dip in ESR and loss tangent at around 100KHz on various
graphs.


** I see no such trend for the electros.

The ESR of most electros is almost constant down to about 500Hz, then rises
to a few times its high frequency value at 50Hz. I believe mobility of the
ions in the electrolyte is the cause.

Electros uniquely have very low Q factors - which means their impedance *
stays low * over a very wide frequency range.

A typical 470uF electro has an impedance under 0.1 ohms from 4kHz to 1MHz as
does the 330uF example in the graphs.

High Q capacitors ( film and ceramic) all have sharp impedance dips at self
resonance.


..... Phil