Design of an X-band active Gilbert cell mixer MMIC using 0.7µm GaAs MESFET process

This paper presents the design of a Gallium Arsenide MESFET based active Gilbert mixer in X-band (7.5 - 9 GHz). Gilbert mixer core fed through passive lumped baluns at RF and Local oscillator (LO) inputs have been used to achieve an isolation of better than 30 dB. An active combiner is designed at low frequency IF (Intermediate frequency) output. This circuit design exhibits a typical conversion gain of 17 dB over the band when pumped with -9 dBm LO power. The achieved P1dB and IIP3 are -4.5 dBm and 0.1 dBm respectively.