The average consumer has relied upon bidirectional RF communication for phone and internet connectivity for years. These devices are either plugged in to wall outlets or rely on large batteries that must be recharged frequently. A new generation of deeply embedded, short-range wireless applications is emerging, fueled by the extreme reductions in cost and power required for sensing and computation afforded by CMOS and MEMS process advancement. The power consumption of wireless communication links, on the other hand, has not scaled down so dramatically. Short range wireless protocols, such as Bluetooth and 802.15.4, have been developed to meet the communication needs of these applications and have already seen substantial commercial success. However, the excessive energy requirements of current commercially available radios, even those aimed at short range WPAN applications, limit the scope and inhibit the growth of the deeply embedded wireless market.