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.

Museum contents are vulnerable to bad ambience conditions and human vandalization. Preserving the contents of museums is a duty towards humanity. In this paper, we develop an Internet of Things (IoT)-based system for museum monitoring and control. The developed system does not only autonomously set the museum ambience to levels that preserve the health of the artifacts and provide alarms upon intended or unintended vandalization attempts, but also allows for remote ambience control through authorized Internet-enabled devices. A key differentiating aspect of the proposed system is the use of always-on and power-hungry sensors for comprehensive and precise museum monitoring, while being powered by harvesting the Radio Frequency (RF) energy freely available within the museum. This contrasts with technologies proposed in the literature, which use RF energy harvesting to power simple IoT sensing devices. We use rectenna arrays that collect RF energy and convert it to electric power to prolong the lifetime of the sensor nodes. Another important feature of the proposed system is the use of deep learning to find daily trends in the collected environment data. Accordingly, the museum ambience is further optimized, and the system becomes more resilient to faults in the sensed data.

In this paper an ultrawide bandwidth double-layered Vivaldi antenna (DLVA) integrated in Radome housing is proposed. First the conventional Vivaldi antenna is designed with bandwidth extended from 1.8 to 6 GHz at VSWR (3 : 1). Then for wider bandwidth, two slots are etched in the antenna ground plane to extend the antenna bandwidth from 1.7 to 9 GHz. For more improvement in antenna bandwidth, circular slots as electromagnetic band-gap structure (EBG) are etched to further extend the antenna bandwidth from 1.45 to 10 GHz. For gain enhancement double layers of Vivaldi antenna ground plane are designed with the same feeding line to reach 29 dBi peak. High frequency structure simulator (HFSS) ANSYS is used to design and simulate all the design steps. The proposed antenna is fabricated and measured. Finally, DLVA is integrated inside the Radome to improve the antenna gain and protect the proposed antenna from environmental factors. The antenna is fabricated and tested, and a good agreement between simulated and measured results is found.

In this letter, Laser Induced Graphene (LIG) as a low cost and versatile technique, was utilized to fabricate coplanar waveguide fed polygon monopole antenna on glass substrates. A modified MoS2-graphene heterostructure based antennas were also fabricated and characterized. The formation of the graphene and the successful realization of the hybrid structures were examined and confirmed by several techniques including SEM, Raman and EDX. The conductivity as well as the reliability over large areas were demonstrated for both materials, concluding a significant improvement of MoS2-graphene heterostructure over graphene antenna. Consequently, the two proposed antennas have shown up to 30% enhancement in gain with respect to a reference fabricated copper- based antenna.

Single and dual linearly-polarized receiving mode nanoantennas are designed for solar energy harvesting at 28.3 THz. The infrared rectennas are used to harvest the solar energy and converting it to electrical energy. The proposed infrared rectenna is a thin dipole made of gold and printed on a silicon dioxide substrate. Different shapes of the dipole arms have been investigated for maximum collected energy. The two poles of the dipole have been determined in a rectangular, circular and rhombus shapes. The rectenna dipole is used to concentrate the electromagnetic energy into a small localized area at the inner tips of the gap between the dipole arms. The dimensions of the different dipole shapes are optimized for maximum near electric field intensity at a frequency of 28.3 THz. A Metal Insulator Metal (MIM) diode is incorporated with the nanoantenna dipole to rectify the received energy. The receiving efficiency of the solar energy collector with integrated MIM diode has been investigated. A dual-polarized, four arms, rhombus shaped nanoantenna dipole for solar energy harvesting has been designed and optimized for 28.3 THz applications.