By Bilal El jaafari and Jean-Marie Floch, Institut d'Electronique et de Télécommunication de Rennes (IETR)
In this work, a high-gain broadband printed Yagi directional antenna for applications in ISM bands (686 and 915 MHz) is presented. The proposed antenna was designed to be implemented in a wireless system, devoted to water and wastewater level and underground flow measurements for the IJINUS Company. It consists of a printed dipole antenna with a reflector, director and an additional parasitic element. These three additional elements were added with the aim of improving the antenna performances.
The present antenna was designed using an optimization process based on global algorithms. Both simulation and optimization are carried out using simulation electromagnetic software tools (Gain and bandwidth). A prototype of the antenna was manufactured and verified experimentally. Good agreement between simulated and measured results is obtained. A high gain of 7dBi in average is obtained over a wideband frequency of about 21% of a band around the central frequency (800 – 950 MHz).