Towards the world smallest wireless sensor nodes with low power consumption for ‘Green’ sensor networks

Pursuit of the lowest size-limit of wireless sensor node may not only reduce production cost and power consumption, but also enable its layout-free ubiquitous applications, especially in `green´ sensor network to compress energy consumption through visibility and optimization. In this work, we engage in developing the world smallest wireless sensor node form both system block integration and physical interconnection points-of-view. A customized RF-transmitter IC with low power consumption, universal interface to analog and digital sensors, and power management function was developed by using 0.18um 1.8V/3.3V 1P6M logic process. By introducing buried bump interconnection technology (B2it™), one of the world smallest wireless sensor nodes for humidity and temperature monitoring was successfully achieved with the size of 3.9×3.9×3.5mm. Configuration of above sensor node also enables its easy assembly with stand-alone power source and flexible antenna for wide variety of applications.