We are happy to anounce that we have been awarded with the grant for bilateral cooperation between Serbia and Montenegro for project “5G-RECTenna: Harvesting and conversion of microwave energy for sensor networks.” Short description of the project is given below.

Connecting the sensor devices in a network has proved useful for automation and optimization of numerous projects, mostly in agriculture and environmental protection. The core element of the IoT concept is a sensor network whose design is in the focus of many researchers and innovators today. Energy is an essential resource limitation of sensor devices, since their sources of power are usually batteries with limited capacity.

One approach to increase the energy efficiency of the sensor network is energy harvesting. This is a new concept that implies the collection and storage of ambient energy from various sources, in this case collecting ambient electromagnetic energy in the microwave frequency band (RF energy harvesting).

The requirements of the sensor nodes for autonomous and stable power supply are placing the possibilities of this technology in the forefront. So far, widespread solar power has been showing numerous shortcomings. In the case of monitoring in agriculture, it often happens that the solar panel is covered with mud and foliage, with reduced efficiency in the winter due to the lack of direct sunlight.

The proposed energy harvesting concept is based on the acquisition of ambient electromagnetic energy using the antennas designed for broadband operation at several frequencies with integrated detector (rectifier), that converts microwave energy to DC. These antennas are usually reffered as rectennas (rectifier + antenna) in the literature. Energy of the collected microwave radiation does not depend on weather conditions or the current season. Collected RF energy is converted by means of RF-DC converters to a DC voltage that charges the battery, or in the case of advanced versions with low-power microcontrollers powers the entire sensor node. The advantages of the RF energy harvesting are: a) easy maintenance of the sensor network - in contrast to batteries, the lifetime of the sensor can be very long if the system is well designed and with constant source of ambient energy, b) it can be used as an auxiliary power which increases reliability of the system, c) it provides the possibility of autonomous power supply of sensor devices.