To address the limited overlapping bandwidth across polarization modes in conventional multi-polarized antennas, this paper proposes a wideband multi-polarized microstrip antenna with high polarization isolation. Based on the theory of orthogonal dual-circular polarization synthesis, the proposed antenna achieves left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) under a single-port excitation mode, and can generate arbitrary linear polarization (LP) by simply adjusting the phase when dual-fed. For verification, a prototype operating at the C-band is designed, fabricated, and measured. The measured results agree well with the simulations. For linear polarization, the measured 10 dB bandwidth ranges from 4 GHz to 8 GHz (relative bandwidth of 66.7%), with polarization isolation exceeding 26 dB. For circular polarization, the measured bandwidth (for 10 dB return loss and 3 dB axial ratio) spans 4.1–8 GHz (relative bandwidth of 64.5%), with polarization isolation greater than 15 dB. The linear polarization gain is slightly higher than the circular polarization gain, with a maximum gain of 4.3 dB. The proposed antenna simultaneously features multi-polarization, a wide bandwidth, a low profile (0.03 λ₀), and high polarization isolation, which can meet the urgent demand for multi-polarized antennas in modern multi-functional integrated wireless systems, such as communication systems, radar, and unmanned aerial vehicles (UAVs).

To address the performance degradation of conventional rare-earth silicate environmental barrier coatings (EBCs) in high-temperature water-oxygen environments, this study developed a novel high-entropy EBC system. The coating with a composition of (Yb_1/5Y_1/5Lu_1/5Er_1/5Ho_1/5)₂Si₂O₇/Si/SiC was prepared via atmospheric plasma spraying. Thermal cycling corrosion tests were conducted at 1400 °C under a 90% H₂O–10% O₂ atmosphere. Results show that after heat treatment, the monosilicate phase content decreased, and the structure stabilized. The coating surface exhibited a ridge-like morphology with pits and microcracks after corrosion. A porous corrosion layer formed at the edges, and the SiO₂ layer thickness increased parabolically from 2.75 μm after 100 cycles to 5.65 μm after 300 cycles. The coating demonstrated excellent corrosion resistance, with degradation initiated by surface thermochemical corrosion, leading to corrosion layer formation and SiO₂ accumulation. This study provides important insights for developing long-life EBCs for aero-engine applications.

This paper proposes a dual-band, full-polarized (dual-sense circular polarization and arbitrary linear polarization) annular-ring slot antenna centered at 2.4 GHz and 5.8 GHz, which effectively overcomes the limitations of narrow bandwidth and limited polarization diversity in conventional designs. By employing an eccentric annular-ring slot and two orthogonal 50-ohm patches, the antenna achieves dual-band circular polarization (CP) radiation with single-port feeding. Based on the theory of orthogonal dual-circular polarization synthesis, arbitrary linear polarization (LP) can be generated by adjusting the phase difference when both ports are fed. The measured results show that the 10 dB return loss bandwidth of LP spans 2–2.8 GHz (relative bandwidth of 33.3%) and 4.5–7.5 GHz (relative bandwidth of 50%), with polarization isolation exceeding 50 dB. For CP mode, the measured bandwidth (for 10 dB return loss and 3 dB axial ratio) ranges from 2.24 to 2.58 GHz (relative bandwidth of 14.1%) and from 5.1 to 6.6 GHz (relative bandwidth of 25.64%), with polarization isolation greater than 15 dB. The proposed antenna simultaneously features a high frequency ratio (2.42), full polarization, high polarization isolation, a low profile (0.008 λ₀), and bidirectional radiation, which can meet the urgent demand of modern information systems for dual-band, full-polarized antennas.