Silver sandwiched ITO based transparent antenna array for RF energy harvesting in 5G mid-range of frequencies

Abstract

A transparent antenna array based on silver sandwiched indium tin oxide (AgITO) heterostructure thin films is presented. The AgITO is sputtered on both sides of soda-lime glass (SLG) substrate, and the three thin films deposition parameters are optimized to obtain very low ohmic interfacial contact resistance of less than 1 Ω/Sq. AgITO promotes thin film-based transparent microstrip structure of the proposed antenna array as well as the transparent T-junction power divider. Furthermore, AgITO microstrip as well as opaque single element antenna as reference antennas for a transparent array are presented. The proposed array has wide bandwidth promoting radio frequency energy harvesting at Wi-Fi 2.4, LTE 2600, WLAN, WiMAX and the expected 5G mid-bands. Moreover, it could be functionalized for wireless transmission within the previously mentioned bands. The transparent AgITO array has 5 dBi gain value against 2.3 dBi for the transparent AgITO single element antenna at 5.8 GHz. The array was utilized for radiofrequency energy harvesting, obtaining DC output volt=161.4 mV with a conversion efficiency of 32.9% at 5.8 GHz with RF received power of −10 dBm.