Cement based patch for low profile rectenna implementation for RF energy harvesting systems

A microstrip patch employing cement substrate for possible implementation as low profile Rectenna system is presented. Design and development of RF energy harvesting systems has renewed research interest in rectenna research domain. A rectangular cement substrate based patch resonating at 1 GHz is analysed for its receiving characteristics. The root mean square (RMS) AC voltage developed at antenna terminal (terminal voltage) upon plane wave incidence is the parameter under consideration. Simulated results employing High Frequency Structure Simulator (HFSS), are observed, and the voltages are in the range 0–5 mV. Experiments are conducted on a prototype structure with cement substrate, and the observed return loss and terminal voltage measurements are encouraging. A terminal voltage of around 5–7 mV is observed for direct plane wave incidence. In practice, direct RF energy incidence is unlikely. Nevertheless, the experimental results are encouraging, and further studies on available terminal voltage over a period of time needs to be undertaken. Development of cement based antennas provides a low profile front end implementation for rectenna systems, thereby enhancing implementation of RF energy harvesting systems in commercial and residential infrastructure.