Subharmonic mixers simplify high frequency designs for personal communications system

This paper presents the analysis and performance of subharmonic mixer for the application in digital microwave radio system. The characteristics of subharmonic mixer are analyzed in terms of conversion loss, LO rejection and 1 dB compression point using Microwave Design Software (MDS) and the large signal harmonic balance techniques. The analysis indicates that a typical 50 dBc 2LO-to-RF isolation of the circuit can be achieved across a wide bandwidth for digital microwave transmitters and receivers. The conversion loss and 1 dB compression point, however, are slightly lower compared to fundamental mixing. Therefore, a trade-off between these parameters should be considered when doing system design.