The development of environmentally tested antennas for wireless sensor networks

Wireless Sensor networks (WSNs) are often viewed as providing solutions to the problems inherent in monitoring large areas over a long time-scale. As such they are often envisaged for use in unstable or harsh environments, such as outdoors or on factory floors. In such places the ambient temperature and/or humidity can often vary over time along with other environmental factors. Variations in these basic defining parameters of an environment may introduce problems to a WSNs performance due mainly to the possible effects on antenna performance. Given that the efficiency of the antenna has a dramatic impact on both range of operation and power usage, it is desirable that its performance be gauged over the entire range of expected environmental effects. The improvement or degradation of the performance of the antenna based on the environment is vital knowledge in the design of a power conscious system. Thus this paper will present the design, simulation and test of antennas designed for use in WSNs over a wide range of temperature and humidity values. The antenna model will be presented, with simulated results. The design of the test system will be discussed, and the performance of various antennas will be presented. The suitable conclusions on the performance of the various antennas in heterogeneous environments, and thus their suitability for WSNs, will be drawn.