Active mixers for direct conversion receivers with 0.35-mu m BiCMOS

In this paper, the design requirements of different mixers for direct conve rsion receivers are discussed. Special attention has been paid into the det ection of amplitude-modulated RF signal envelope. Three active mixers have been implemented to investigate the discussed requirements by using a 0.35- mu m, 25-GHz BiCMOS technology. The same process allows an objective compar ison between the different topologies. The mixers are designed for a single 2.7 V supply, and specified for low power consumption. Different topologie s are compared by their spurious free dynamic ranges (SFDR) with respect to their individual power consumption. Also, their performance were measured at different LO power levels and supply voltages. The results show insignif icant differences between the topologies in low voltage applications.