Frequency

Capacitance frequency dependance

in polypropylene capacitors (PP, MKT), the capacitance remains virtually unaffected by frequency up to 1 MHz. In polyester capacitors (PET, MKT) and especially in PEN capacitors (polyethylene naphthalate, MKN), the effect of frequency is more noticeable:

Additionally, in the vicinity of the natural resonant frequency of the capacitors, self-inductance leads to an additional decrease of impedance. This has the same effect as an increase in capacitance

Source: Epcos-TDK, modified by Garmanage: Roland Gallay