How the capacitance varies as input power varies in a mmW RFIC PA?

Hello, all

I read that the input capacitance in a cascode cell varies as input power varies in a mmW RFIC.

Could anyone explain me how this happens? Is it an effect of the Miller effect?

Many thanks!

Almost all intrinsic capacitors in a semiconductor device behave like varicap diodes.So reverse polarized but bias and signal amplitude dependent.
Hence, it shouldn't be a surprise capacitor value is amplitude dependent if the amplitude is sufficiently high.