In this paper, a multifunctional frequency selective rasorber (FSR) based on hybrid microfluidic-electronic control is presented. The proposed FSR consists of a photosensitive resin-based microfluidic channel and an active frequency selective surface. The lossy layer utilizes the special properties of water (dispersion characteristics, fluidity), and has great advantages in low profile, multifunction, and low costs. Four different responses are realized by the combination of two independent control systems, which provide more degrees of freedom for manipulating electromagnetic waves. In addition, the distribution of electric fields and power loss densities are thoroughly analyzed to derive the physical properties of the proposed structure. Finally, a multifunctional FSR is fabricated and measured, and the simulated and tested results are in good agreement. The proposed structure performs under different polarizations and incident angles (up to 30°), which ensures the stability and security of the communication system in complex environments.

In this paper, a novel integrated metasurface antenna (MA) unit is proposed, capable of achieving in-band and out-of-band radar cross-section (RCS) reduction through angular rotation. At operating frequency of 9.15 GHz, the proposed metasurface antenna with U-slot (MAUS) unit exhibits a 180° reflection phase difference under x- and y-polarized incidence conditions, allowing 0° and its 90° rotating unit to achieve co-polarized scattering cancellation in-band. Consequently, this design realizes RCS reduction by the array itself. Concurrently, equivalent circuit theory is employed to elucidate this phenomenon. A ring-shaped frequency selective-absorber (FSA) unit is loaded above the MAUS unit to effectively suppress out-of-band signal interference. Furthermore, the reflected beam control and radiation characteristics of a 1-bit encoded MAUS array are simulated and compared. Therefore, the antenna array with a 4 × 4 subarray configuration is optimized and fabricated, in which the output phases of four subarrays are 0°, 270°, 0°, and 270°, respectively. The simulation and measurement results demonstrate that the proposed antenna system is able to cover 8.70 GHz–9.73 GHz with good right-handed circular polarization (RHCP) radiation performance and a maximum gain of 15.9 dBi. Moreover, it has been observed that antenna arrays exhibit disparate levels of RCS reduction performance within an incident angle of 45°. The proposed integrated antenna array is poised to be a suitable option for devices that require both efficient radiation management and enhanced stealth capabilities.

To enhance the purification of exhaust gas, a g-C₃N₄/CeO₂/Bi₂O₃ dual type-II heterojunction photocatalysis was designed and prepared to suppress the recombination of electron–hole pairs and improve light energy utilization. The dual type-II heterojunction structure effectively reduced the bandgap (Eg) from 2.5 eV to 2.04 eV, thereby extending the light absorption of photocatalysis into the visible region. Following the design of the heterojunction, a self-cleaning process was developed and applied to asphalt pavement rut plates to evaluate its efficiency in degrading vehicle exhaust under real-road conditions. The coating was systematically characterized in terms of exhaust degradation efficiency, hardness, adhesion, water resistance, freeze–thaw durability, and skid resistance. Under 60 min of natural light irradiation, the purification efficiencies for HC, CO, CO₂, and NO_x reached 22.60%, 19.27%, 14.83%, and 50.01%, respectively. After three-repetition tests, the efficiencies remained high at 21.75%, 19.04%, 14.66%, and 49.83%, demonstrating excellent photocatalytic stability. All other road-performance indicators met the relevant China national standards. The application of this self-cleaning coating in road infrastructure presents a viable strategy for environmental remediation in transportation systems.

In this paper, a novel high-shielding-effectiveness energy-selective surface (HSE–ESS) is proposed. In previous solutions regarding energy-selective surfaces (ESSs) presented in the literature, PIN diodes are usually employed as nonlinear transmission components; however, these diodes may be burnt by powerful high-power microwave (HPM) beams, causing ESSs to lose their shielding effectiveness (SE). To date, no studies have focused on maintaining the SE performance of ESSs after PIN diode failure. To address these limitations, we introduce shape memory alloys (SMAs) into ESS design. The consequences of PIN diode failure are offset by the physical deformation of SMA components caused by high-amplitude-current heating. This characteristic, featuring 30 dB SE, can be defined as high shielding effectiveness (HSE). After completing the design and performing accurate numerical simulations, we fabricated a prototype using PCB technology and characterized it in an anechoic environment, verifying the overall method. In particular, the SMA components proved to be an effective medium for guaranteeing electrical continuity under thermal stress conditions, thus paving the way for their extended adoption in ESSs by substituting or acting as a back-up for PIN diodes. Overall, this approach enhances the reliability and SE of ESSs by adding SMA components.

In this paper, a novel low-complexity and cost-effective switchable frequency selective rasorber (SFSR) with polarization-independent switching capability is proposed. To our best knowledge, previously reported electronically reconfigurable and polarization-independent SFSR configurations requires at least 3 distinct layers with no less than 20 SMD lumped components for each unit-cell, causing high cost and fabrication complexity. Conversely, the herein developed switchable rasorber contains only 2 layers with 6 SMD lumped elements for each unit-cell, thus significantly simplifying fabrication and reducing overall cost. To achieve the independent control over TE and TM polarizations, we separate the structure design in perpendicular directions. Two switchable bands are accomplished, whose working mode can be changed from transmission to absorption and reflection to transmission respectively, while only one is usually possessed by previous literature results. By switching the operating state of PIN diodes, the SFSR working mode type is A–T/A–A–R/T. For A–T–A–R mode, it exhibits S 11 ⩽ − 10 dB low reflection band of 2.89–8.74 GHz, with 1.17 dB insertion loss. For A–A–A–T mode, it exhibits low reflection band of 3.67–8.2 GHz. Besides, the SFSR has angle stability of 30 ∘ . After the design process and numerical simulations evaluation, prototypes are fabricated through PCB technology and characterized in anechoic environment, confirming the overall approach. This work improves about 43% cost effectiveness under same capabilities and it is particularly suitable for all the applications requiring low-complexity and cost-effective fabrication, such as unmanned equipment and antennas radome.

This paper proposes a structural silicon heterojunction photosensitive element with a simple form, low manufacturing cost, and efficient performance, which has a high-intensity photoelectric effect and a high frequency range of use. It can be applied as microwave switches to active frequency selective surfaces (AFSSs) to replace PIN diodes. Meanwhile, we explore the crucial role of pentacene/silicon heterojunction in the photoelectric conversion process. It is found that due to the inherent photovoltaic effect and the built-in electric field interaction between the two materials, the insertion loss of the heterojunction formed is reduced to 4.5 dB, which is 2.5 dB lower than that of the high-resistivity silicon wafer. In order to further reduce the insertion loss, the surface of the silicon wafer is etched and then heterojunction is prepared, which can further reduce insertion loss to within 2.5 dB, and the bandwidth difference between the presence and absence of pump excitation exceeds 10 dB extends to 12 GHz, indicating that the light collecting ability of structural silicon significantly enhances its photoelectric effect. The research results demonstrate the potential of using structural silicon heterojunctions in photoelectric devices, providing new technology for high-performance microwave switches and implementing optically controlled FSSs.