Ultra-Low Power Wireless Technologies for Sensor Networks

transconductance e? ciency of all critical devices in order to reduce the n- essary bias current. However, reducing the current density also results in a severely decreased device f . An optimization of the current density is re- T quired to provide the correct balance between transconductance e? ciency and bandwidth. Plots such as Figure 2. 1 are useful tools for designers when choosing appropriate transistor bias points. Technology scaling allows greatly increased f realization for a given IC. Thus, weak inversion biasing for RF T design will become increasingly useful in future technology nodes. Throughout this work, the IC of critical transistors will be discussed. Most of the RF devices are biased in moderate to weak inversion to achieve enhanced transconductance e? ciency and reduced bias current. 2. 2 MEMS Background The relatively new ? eld of Radio Frequency Microelectro Mechanical Systems (RF MEMS) provides unique opportunities for RF transceiver designers. This section provides background on RF MEMS and provides insight into the - portunities presented by these new technologies. The ? eld of RF MEMS - cludes the design and utilization of RF ? lters, resonators, switches, and other passive mechanical structures constructed using bulk processed integrated c- cuit fabrication techniques. To date, these devices have been commercially used as discrete board-mounted components, primarily used to enhance the miniaturization of mobile phones. However, RF MEMS components have the potential to be batch fabricated using existing integrated circuit fabrication techniques.