A phase detector is implemented by IQ method and calibrated to obtain the dynamic ranges of input signals which results in stable DC outputs. Of the two input ports, the optimum power at one is 8 dBm and the other is more than -30 dBm. Under this condition, the measured calibration angle is 34˚. The effect of harmonic frequencies upon phase error is measured, and when the harmonic frequency's power is equal to or less than that of a center frequency, the phase error is less than 5˚. FET mixers and band pass filters are designed and used in implementing overall phase measurement system. At this time, the phase detector detects the phase information which is transferred to IF output signals of mixers. The measured phase error is less than 5˚ also, if the optimum power is given at the input of phase detector.
