The present invention relates to a phase detector circuit (10) having an RF distribution device (20) which is intended to receive two sinusoidal high-frequency signals (RF, LO) with an input phase difference (φRF(t)−φLO(t)) and comprises two power splitters (21, 22) in order to split the two high-frequency signals (RF, LO) into two respective parts, a self-calibrating phase detector module (30) which is configured to receive one respective part of the two high-frequency signals which have been split, a low-noise phase detector module (40) which is configured to receive the respective other part of the high-frequency signals which have been split, and a complementary filter device (50) which is configured to receive the output signals from the self-calibrating phase detector module (30) and the low-noise phase detector module (40) and to output a signal which indicates the time-dependent input phase difference between the two high-frequency signals (RF, LO).