Abstract: A microwave CMOS six-port system working in a frequency range of 1.7~2.3 GHz was designed.The correlation between voltage and power was determined with polynomial interpolation from power data.The reflecting coefficient of the system was tested with CMOS MIC(microwave integrated circuit)technique.The maximum difference among the measured ports was about 8 dB,the magnitudes of q points(q4,q5 and q6) were larger than 1,and the phase distribution at 2 GHz was the best,with phase differences of 97°,133°and 130°.No distinct changes in the system performances were observed with a 10% component tolerance.Compared with the results by a vector network analyzer,the biggest phase and magnitude errors in the operation band were 3°and 0.7 dB,respectively.