Energy Harvesting Solution for Wireless Sensors in IoT Applications

This book addressees design, fabrication, measurement of different antennas for RF energy harvesting. An indoor, outdoor survey on the RF spectrum at different locations and time slots are presented for determining the frequencies of maximum ambient radio frequency power. Linearly polarized and dual linearly polarized antenna arrays are introduced for increasing the amount of the harvested power at low level of energy density. Transparent antennas on two different transparent thin films of commercial indium tin oxide (ITO) and new developed silver sandwiched ITO (AgITO) heterostructure thin films are designed, fabricated, measured and utilized for RF-EH system. The RF/DC sputtering is functionalized to deposit the AgITO on both sides of soda-lime glass (SLG) substrate, obtaining sheet resistance (Rs) blow 1¿/Sq. that is coupled with ~52% transparency (T) at wavelength of 550 nm. The associated 3 thin films deposition parameters were optimized in order to obtain very low ohmic interfacial contact resistance. Furthermore, commercial ITO with thickness of 150nm and Rs =8 ¿/Sq. on SLG substrate was used to fabricate transparent ITO antennas of T=93% at wavelength of 550 nm.