Design and implementation of the multi-frequency hybrid energy harvester

In this thesis, the design and implementation of a novel multi-frequency hybrid energy harvester, which consists of a combination of monopole rectenna and solar cell, has been carried out to meet the energy needs of low-power systems such as wireless sensor networks. The leaf shaped monopole antenna is designed by inspiring the nature and has a broadband structure to cover the most commonly used communication frequency bands (GSM-1800, UMTS-2100, WIFI-2.45, LTE-2.65 GHz). In order to suppress the high-order harmonics generated by the diode in the rectifier circuit and to obtain a better efficiency from the antenna, the single stub low pass filter is designed and placed on the feeding line of the antenna and the operating frequency range of the antenna is limited. The solar cell is placed on the ground plane of the antenna in order to better use the volumetric space. The half wave rectifier is designed and tested to operate at the entire interested frequency bands efficiently with the help of the SMD circuit elements and microstrip transmission lines. At the test measurements of the implemented energy harvester in the indoor environment, it has been observed that it has an output voltage value of 110 mV and a power generation value of 21.2 μW under -20 dBm RF power and 165 lux irradiance value. The obtained results show that the designed system can be used to feed low power sensor networks and micro - electronic systems.