TheRFdesignparadigm will changesignificantly asCMOS technology scales and integration levels rise to accommodate multi-band, multi-mode transceivers and baseband processors. This paper describes technology scaling issues such as low supply voltages, high gate leakage currents, and low transistor output impedances. Also, design techniques for low-voltage mixers are presented, and stacked and nested inductors are proposed to achieve compact layouts for multi-band systems.