You know, at low frequency, the impedance of an inductor coil is proportional to the frequency. However, as the frequency turns high, the impedance of the whole inductor coil will decrease rapidly due to the existence of the inductance distributed capacitance.

That is to say, the impedance of the inductor coil increases with the increasing of frequency first. Then it reaches the maximum value when it ups to the SRF(Self-Resonant Frequency). Finally, the impedance of an inductor decreases rapidly to 0. BTW, if the frequency is higher, the inductance coil will be capacitive.