• Book : 11(1)
• Pub. Date : 2025
• Page : pp.04024074
• Keyword :

• Book : 6()
• Pub. Date : 2025
• Page : pp.100391
• Keyword :

Abstract

A high-gain transmitarray antenna with low radar cross section (RCS) properties is presented in this paper. Compared with conventional high-profile multilayer designs, we introduce a transmit-reflect selective metasurface integrated with high-gain transmission and random scattering functions, achieving a reduced thickness of 0.13 λ0 (where λ0 is the wavelength at the center frequency). For the meta-atom design, we combine geometric rotation and dimension optimization to realize 1-bit independent transmit and reflection phase modulation, respectively. Moreover, in metasurface coding strategy, we employ an initial phase optimization method and a simulated annealing algorithm to determine the optimal coding matrices. The experimental results demonstrate high-performance radiation characterized by the peak gain of 23.6 dB, maximum aperture efficiency of 28.5%, and 3 dB gain bandwidth of 18.4%. For x-polarization, measured 10 dB RCS reduction bandwidth under transverse magnetic (TM) 0°-45° and transverse electric (TE) 0°-20° incidence are 9.02-11.36 GHz. For y-polarization, 10 dB RCS reduction bandwidth under TM 0-60° and TE 0-30° incidence is 8.82-10.96 GHz.

• Book : 58(1)
• Pub. Date : 2025
• Page : pp.015107
• Keyword :

Comprehensive understanding of the direct transformation pathway from graphite to diamond under high temperature and high pressure has long been one of the fundamental goals in materials science. Despite considerable experimental and theoretical progress, current experimental studies have mainly focused on the local microstructural characterizations of recovered samples, which has certain limitations for high-temperature and high-pressure products, which often exhibit diversity. Here, we report on the pressure-induced phase transition behavior of natural single-crystal graphite under three distinct pressure-transmitting media from a macroscopic perspective using in situ two-dimensional Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. The surface evolution process of graphite before and after the phase transition is captured, revealing that pressure-induced surface textures can impede the continuity of the phase transition process across the entire single crystal. Our results provide a fresh perspective for studying the phase transition behavior of graphite and greatly deepen our understanding of this behavior, which will be helpful in guiding further high-temperature and high-pressure syntheses of carbon allotropes.

• Book : 10(1)
• Pub. Date : 2025
• Page : pp.017801
• Keyword :

• Book : 56(1)
• Pub. Date : 2025
• Page : pp.101769
• Keyword :

• Book : 12(suppl1)
• Pub. Date : 2025
• Page :
• Keyword :

• Book : 258(pb)
• Pub. Date : 2025
• Page : pp.124647
• Keyword :

• Book : 50()
• Pub. Date : 2025
• Page : pp.100880
• Keyword :

• Book : 381(2)
• Pub. Date : 2025
• Page : pp.133338
• Keyword :

• Book : 151()
• Pub. Date : 2025
• Page : pp.469-483
• Keyword :