RF Characteristics of Mica-Z Wireless Sensor Network Motes

The RF characteristics of Mica-Z wireless unattended sensor motes were evaluated for military and commercial applications. The Mica-Z mote's propagation characteristics and network performance were measured under near free- space, indoor and outdoor environments to provide a comprehensive perspective of typical sensor network characteristics. Link break distance and re-association distance with their corresponding RF power measurements were recorded to determine the Mica-Z's range characteristics under different operating environments. Power Loss exponents were also estimated to provide Mica-Z users a faster and more convenient way to estimate operating ranges in the different environments. A graphical numeric electromagnetic code (GNEC) simulation was also used to investigate some of the possible improvements that could be made to the existing Mica- Z antenna design to enhance the performance of the sensor network. This paper substantiates the difficulties of operating such sensor networks in the most hostile environments. Although the analyses demonstrate that controlled deployment was possible to some extent, the effectiveness of random deployment remains challenging.