A novel RF induced power supply system for monolithically integrated ubiquitous micro sensor nodes

In this paper, a novel radio frequency (RF) induced power supply system for micro sensor nodes is presented. The system receives RF-electromagnetic wave of a mobile phone and rectifies it to generate a DC voltage by a rectenna (a rectifying circuit with an antenna). A charge pump (CP) circuit boosts up an output voltage of the rectenna, and the boosted voltage is stored to a large capacitor. When the boosted voltage of CP circuit reaches to an arbitrary voltage, a switch circuit between the output of CP circuit and an input of a voltage regulator turns on and supplies a regulated DC voltage to a load through the voltage regulator. The power supply system mounts one Schottky barrier diode (SBD) and three large value capacitors of surface mount devices (SMD) on deep holes fabricated by deep reactive ion etching (DRIE) process around CMOS circuits. The system was fabricated with 0.6 μm-CMOS technology, and can supply well-regulated 4.0 V/1 mA DC power to the load for 10 ms periodically.