Adaptive, functional, and reconfigurable devices that can manipulate incoming electromagnetic (EM) waves of arbitrary polarization into any desired output polarization are essential for advancing a wide range of Internet of Things (IoT)-related applications, including smart wireless communications, radar, imaging, and sensing systems. Achieving this functionality requires precise control over both the amplitude and phase of co-polarized and cross-polarized components—a task that presents significant challenges. In this work, we present a novel electrically Reconfigurable Intelligent Surface (RIS) capable of controlling all three fundamental EM wave properties: amplitude, phase, and polarization (encompassing both co- and cross-polarized components). The RIS leverages a field-programmable gate array (FPGA) to enable real-time, on-demand reconfiguration of its EM response. By employing far-field optimization techniques to determine the required amplitude and phase distributions for both polarization components, we demonstrate—through proof-of-principle applications—the RIS’s ability to dynamically steer beams, shape wavefronts, and arbitrarily transform polarization states. This advancement underscores the RIS’s potential as a transformative component for next-generation wireless systems, imaging technologies, and information processing applications, offering significant improvements in both performance and functionality across diverse fields.

This paper investigates the hollow-core ceramic (alumina) fiber for millimeter-wave communications at high temperatures, up to 1100°C. Such interconnects will benefit extreme environment electronics used across many industries, including aerospace, avionics, and geothermal. We first study EM wave propagation through alumina fiber across 50-75 GHz range at high temperatures. The results show that the transmission magnitude decreases non-linearly as temperature increases. Furthermore, it remains stable with a variation of < 0.5 dB during one hour of heat exposure at 1100°C. Next, the fiber is paired with a 57 GHz CMOS transceiver to demonstrate high speed communication link at high temperatures. To compensate for temperature-related transmission variations, an automatic gain control loop is implemented in the receiver chain. The proposed system attains a data rate of 5 Gb/s. Our findings indicate that ceramic fibers offer desirable features, such as high melting point, low thermal conductivity, and good EM wave propagation at elevated temperatures, making them suitable for communication and sensing in harsh environments encountered during hypersonic flight or planetary exploration.

Reconfigurable Intelligent Surface (RIS) is a promising technology for enhancing wireless networks in challenging environments. While existing RIS designs can manipulate basic electromagnetic properties like amplitude and phase, it lacks control over polarization. This paper presents a novel RIS design with four independently controllable varactors. This design enables independent and continuous tuning of amplitude and phase for both co-polarization and cross-polarization channels, providing greater flexibility and improved performance in next-generation wireless networks. A fabricated prototype showcases two key functionalities: beam-steering with combined amplitude control, and beam-steering with six user-defined distinct polarizations.

A comprehensive review of 3-D/4-D-printed reconfigurable metasurfaces (RMSs) is presented in this article. A metasurface (MS) demonstrates exceptional abilities for electromagnetic (EM) wave molding beyond that offered by conventional planar interfaces, and RMS provides MS with more diverse EM wave-control capabilities. RMSs are categorized by the type of external stimulus used for reconfiguration, such as electrical RMS, fluidic RMS, mechanical RMS, and thermal RMS. To implement these RMSs, it is important to understand the design and fabrication requirements as well as the EM characteristic of each RMS, including its advantages and disadvantages. In particular, except for electrical RMS, RMSs require complex 3-D structures or special materials that are difficult to implement with conventional subtractive manufacturing methods such as printed-circuit-board manufacturing. Recently, advanced 3-D/4-D printing technology has achieved high fabrication freedom and meets the design and fabrication requirements of each type of RMS. In this article, we introduce representative RMSs with the development of 3-D/4-D printing technology and materials. Furthermore, current issues of RMSs based on 3-D/4-D printing technology and future directions are described.