Predicting Ground Effects of Omnidirectional Antennas in Wireless Sensor Networks

• 作者: Jeffrey J. Evans John F. Janek
• 来源期刊: 无线传感网络(英文)
• 学科: 工学
• 关键词: OMNIDIRECTIONAL ANTENNA GROUND EFFECTS WIRELESS Densor NETWORKS
• 年，卷（期）: 2010,（12）
• 页码范围: 879-890
• 页数: 12页
• 分类号: TN92

摘要

Omnidirectional antennas are often used for radio frequency (RF) communication in wireless sensor networks (WSNs). Outside noise, electromagnetic interference (EMI), overloaded network traffic, large obstacles (vegetation and buildings), terrain and atmospheric composition, along with climate patterns can degrade signal quality in the form of data packet loss or reduced RF communication range. This paper explores the RF range reduction properties of a particular WSN designed to operate in agricultural crop fields to collect aggregate data composed of subsurface soil moisture and soil temperature. Our study, using simulation, anechoic and field measurements shows that the effect of antenna placement close to the ground (within 10 cm) signi?cantly changes the omnidirectional transmission pattern. We then develop and propose a prediction method that is more precise than current practices of using the Friis and Fresnel equations. Our prediction method takes into account environmental properties for RF communication range based on the height of nodes and gateways.