The emergence of metasurfaces provides a novel strategy to tailor the electromagnetic response of electromagnetic waves in a controlled manner by judicious design of the constitutive meta-atom. However, passive metasurfaces tend to perform a specific or limited number of functionalities and suffer from narrow-frequency-band operation. Reported reconfigurable metasurfaces can generally be controlled only in a 1D configuration or use p-i-n diodes to show binary phase states. Here, a 2D reconfigurable reflective metasurface with individually addressable meta-atoms enabling a continuous phase control is proposed in the microwave regime. The response of the meta-atom is flexibly controlled by changing the bias voltage applied to the embedded varactor diode through an elaborated power supply system. By assigning appropriate phase profiles to the metasurface through voltage modulation, complex beam generation, including Bessel beams, vortex beams, and Airy beams, is fulfilled to demonstrate the accurate phase-control capability of the reconfigurable metasurface. Both simulations and measurements are performed as a proof of concept and show good agreement. The proposed design paves the way toward the achievement of real-time and programmable multifunctional meta-devices, with enormous potential for microwave applications such as wireless communication, electromagnetic imaging, and smart antennas.

The Airy beam, known to present particular unique features, such as diffraction-free, self-healing, and self-bending, has attracted considerable interest in recent years. Here, an electronically controlled reflective coding metasurface is exploited to generate and dynamically manipulate the Airy beam over a wide frequency band in the microwave regime. By judiciously controlling the external dc bias voltage applied to the programmable metasurface, two distinct control states, “0” and “1”, are engineered as digital codes for −π/2 and +π/2 phase responses, respectively. The programmable binary-phase-coding metasurface enables the generation and active reshaping of the Airy beam to be numerically simulated and experimentally validated. Moreover, the metasurface allows the bandwidth limitation of passive counterparts to be overcome and is able to modulate electromagnetic waves over a broad frequency range, spanning from 9 to 12 GHz, to realize diffraction-free Airy beams.

In this Letter, a transmission–reflection integrated programmable metasurface, which achieves quasi-360° phase coverage in the reflection mode and 1-bit phase coding in the transmission mode, is proposed. The steering manipulation of the zeroth-order Bessel beam is investigated over an angular range of 10°–30° in the reflection space, verifying the reconfigurability of the proposed metasurface. Correspondingly, in the transmission space, beam steering is achieved from −10° to −30°, thereby showcasing full-space scanning capabilities. Both numerical simulations and experimental measurements exhibit good consistency, validating the effectiveness of the designed metasurface. The demonstrated capabilities of the proposed metasurface pave the way for adaptive beamforming, intelligent signal routing, and multifunctional wireless systems that demand full-space wave manipulation.

Extreme working environments with temperatures exceeding 800 °C often result in the failure of conventional sensors. Recently, ceramic–based microwave backscattering wireless passive high–temperature sensors have emerged as viable alternatives. Typically, waveguide transmission lines–integral components of these sensors–are fabricated on ceramic substrates using 3D manufacturing techniques such as drilling and metal backfilling. Nevertheless, tolerances in drilling and backfilling are unavoidable. These tolerances are further aggravated by non–reversible pore expansion at extremely high temperatures, may lead to sensor cracking or complete failure. In the present study, we introduce a metamaterial high–temperature sensor that utilizes an all–planar substrate–integrated waveguide. The sensor’s components are manufactured on alumina ceramic substrates exclusively through screen–printing, obviating the need for drilling. This approach effectively circumvents issues related to pore induced errors or failures and offers the advantages of ease of fabrication and cost–effectiveness. For sensing, a single square complementary split resonant ring (S–CSRR) serves as the metamaterial resonator, providing the requisite temperature sensitivity. In the antenna segment, a coplanar waveguide–fed monopole antenna with a bandwidth of 2.3 GHz is employed. Three types of metal slurry–Ag, PtRh10, and Pt–are utilized in sensor fabrication, rendering them suitable for maximum measurement temperatures of 800, 1200, and 1600 °C, respectively. The average temperature sensitivities for these three sensors are 236, 220, and 191kHz/°C, respectively. The proposed sensor, characterized by high integration, simplified processing, reduced fabrication costs, and a high Q–factor, holds significant application potential in industries such as aerospace, steel metallurgy, and energy mining.

A design of ultra-short integrated polarization rotator (PR) with nonlinear and flat-tip tapers is demonstrated theoretically. Based on mode-evolution theory and three-dimensional (3D) finite-difference time-domain (FDTD) simulation, raised cosine profiled tapers are introduced and optimized in the transition region, which improve the polarized modes coupling and decrease the conversion length to 6 μm for the wavelength of 1.55 μm. Numerical simulations obtain extinction ratio of 32 dB and loss of 0.14 dB with practical material parameters. The method and result presented here can be extremely valuable for applications in polarization diversity circuits.

A metasurface capable of flexibly manipulating electromagnetic waves to realize holograms presents significant potential in millimeter-wave imaging systems and data storage domains. In this study, full-space three-dimensional holograms are realized from a reflection–transmission integrated reconfigurable metasurface, which can achieve nearly 360° phase coverage in reflection space and 180° phase coverage in transmission space. By adjusting the voltage applied to the constituting electronically tunable meta-atoms of the metasurface, an octahedron hologram constituted by three hologram images in different focal planes is generated in the reflection space at 6.25 GHz. Moreover, a diamond hologram, also composed of three hologram images in different focal planes, is achieved in the transmission space at 6.75 GHz. Both the numerical simulation and experimental measurement are performed to validate the full-space holograms implemented by the modified weighted Gerchberg–Saxton (WGS) algorithm with specific phase distribution in different imaging planes. The obtained results pave the way for a wide range of new applications, such as next-generation three-dimensional displays for immersive viewing experiences, high-capacity optical communication systems with enhanced data encoding capabilities, and ultra-secure anti-counterfeiting solutions that are extremely difficult to replicate.