20GHz low power CMOS single chip receiver using resonant transformer techniques for enhanced demodulation efficiency
Smart Dust Systems (SDSs) are typically very low cost wireless ad-hoc networks distributed over a relatively small area which sense, transmit and receive signals. They can be used in applications such as health monitoring, environment sensing and temporal wireless services [1]. The distributed network is composed of wireless nodes, each including antennas, transceivers and digital controllers. Minimizing both cost and power are important requirements for SDS applications. SDSs also require that each node has very small dimensions that are on the cubic millimeter scale. It is difficult to fit an antenna into such a small volume. For example, at 2 GHz, a half-wave dipole antenna is 7.5cm [2]. Using low loss dielectric material, the state of the art FICA (F-Inverted Compact Antenna) at 2.2 GHz has a size of 12mm × 12mm × 3mm [2]. This is still larger than the SDS requirement. Since the chip size is commonly a few mm2, it is clear the antenna size dominates the system size. High frequency operation is a promising way to reduce antenna size since it is inversely proportional to the carrier frequency. For example, theoretically a FICA antenna can be scaled to millimeter range at 20 GHz. To achieve the millimeter size requirements, while also minimizing cost, in this work, we take advantage of CMOS scaling to design an inexpensive 0.13µm CMOS-based amplitude shift keying (ASK) radio frequency receiver that operates at 20 GHz. Resonant transformer circuits which increase voltage levels have also been used to improve system sensitivity [1,3].