Tutorial: Terahertz beamforming, from concepts to realizations

The terahertz range possesses significant untapped potential for applications including high-volume wireless communications, noninvasive medical imaging, sensing, and safe security screening. However, due to the unique characteristics and constraints of terahertz waves, the vast majority of these applications are entirely dependent upon the availability of beam control techniques. Thus, the development of advanced terahertz-range beam control techniques yields a range of useful and unparalleled applications. This article provides an overview and tutorial on terahertz beam control. The underlying principles of wavefront engineering include array antenna theory and diffraction optics, which are drawn from the neighboring microwave and optical regimes, respectively. As both principles are applicable across the electromagnetic spectrum, they are reconciled in this overview. This provides a useful foundation for investigations into beam control in the terahertz range, which lies between microwaves and infrared light. Thereafter, noteworthy experimental demonstrations of beam control in the terahertz range are discussed, and these include geometric optics, phased array devices, leaky-wave antennas, reflectarrays, and transmitarrays. These techniques are compared and contrasted for their suitability in applications of terahertz waves

Terahertz beam focusing based on plasmonic waveguide scattering

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich. - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively

Designing a Flexible and Transparent Ultrarapid Electrothermogenic Film Based on Thermal Loss Suppression Effect: A Self-Fused Cu/Ni Composite Junctionless Nanonetwork for Effective Deicing Heater

Transparent heaters (THs) are one-size-fits-all materials used in electronics such as smart windows, wearable applications, and deicing devices. Copper-based THs, which are the most promising materials, still face some problems such as increasing electrical resistance at the intersections of each nanowire and easy degradation owing to oxidation. To overcome these problems, the formation of a junctionless network whose nanowire intersections are fused by using a composite of copper and the oxidation-resistant material is considered as one of the best strategies. Herein, we report a junctionless copper/nickel-nanonetwork-based TH formed on a polymer nanofiber by combining electrospinning and electroless deposition. This two-step wet process enables the formation of a junctionless network composed of a copper/nickel alloy. The THs showed outstanding heating characteristics (the power efficiency reached 421.7 °C cm²/W) which are suitable for the deicing application. Furthermore, we revealed that prominent heating characteristics are realized because of decreasing thermal loss at intersections during application of current, which we term “thermal loss suppression effect”. Simulating thermal losses at intersection models of a junctionless network and a junction network based on the finite element method, we estimated the thermal loss originated from the network geometry. This insight may contribute to the design of high-performance electrothermal materials