Input and output matched SiGe RF Mixer with High Dynamic Range

Abstract

Based on the Gilbert Mixer topology, an active mixer operating at 2.15 GHz is designed by using the transistors which are realized by using 0.25um SiGe technology. The active balun circuit at the input is realized by using the CB(common base) and CE(common emitter) transistors. The passive capacitive voltage-series feed-forward circuit is applied to CB circuit and an almost perfect broadband matching is obtained at the input. Theoretical calculations are done for noise figure. Current reduction technique is applied to switching transistors for noise decrease. Noise figure is decreased about 3 dB with current reduction. Mixer is simulated with AWR software environment. 5V DC supply voltage is used, OIP3 of 24.7 dBm and the Conversion Gain of 3 dB is obtained for the -2.5 dBm of LO power. The noise figure of the circuit is simulated as 11.75 dB.