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A Wideband Polarization-Reconfigurable Water Dielectric Resonator Antenna
摘要： A water dielectric resonator antenna (DRA) with reconfiguration and broadband characteristics is presented. By injecting pure water into various cavities of the plexiglass holder, the antenna can be switched among left hand circular polarization (LHCP), right hand circular polarization (RHCP) and linear polarization (LP) in almost the same operating frequency range. With the high relative permittivity, water acts as a dielectric resonator as well as an interface similar to electric wall to form a broad axial ratio bandwidth. Thus a broad usable bandwidth is measured to be over 22%, and the measured radiation efficiency and realized gain centralize in 60%-70% and 3-4 dBi respectively.
关键词： dielectric resonator antenna,water antenna,broad bandwidth,dielectric dense patch antenna,reconfigurability
更新于2025-09-23 15:22:29
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Evolution from Air-Cladded to Effective-Medium-Cladded Dielectric Waveguides
摘要： Integrated guiding structures with low loss, low dispersion and broad bandwidth are demanded in high-performance terahertz systems. In this work, an effective-medium-cladded waveguide fabricated on a single high-resistivity silicon wafer is proposed for terahertz operation. The effective medium is realized by regularly perforating a silicon slab with a period in the subwavelength region. The simulated average attenuation coefficient is around 0.05 dB/cm over the operation frequency range from 220 GHz to 330 GHz for the (cid:2)(cid:3)(cid:3) (cid:4) mode.
关键词： low loss,terahertz waveguides,low dispersion,effective-medium-cladded waveguide,broad bandwidth
更新于2025-09-12 10:27:22
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Fast and Simultaneous Determination of Soil Properties Using Laser-Induced Breakdown Spectroscopy (LIBS): A Case Study of Typical Farmland Soils in China
摘要： This work provides a new paradigm for designing a laser crystal requiring a broad luminescent spectrum through spontaneous polarization and local structural disorder. The grown complex ferroelectric crystals Nd-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (Nd:PMNT) have a broad emission spectrum with a full width at half-maximum value of 30 nm, much larger than typical Nd laser crystals (Nd:YAG ≈ 0.8 nm). The internal mechanism of spectral broadening in complex ferroelectric crystals was analyzed using the con?guration coordinate. The shift of the peak site in the 4F3/2 → 4I11/2 transition with temperature was a?ected by structural changes, consistent with the change in dielectric and ferroelectric properties. The family of complex ferroelectric crystals could be an abundant treasure for Nd femtosecond laser crystals requiring a broad luminescent spectrum.
关键词： local disorder,spontaneous polarization,ferroelectric crystals,Pb(Mg1/3Nb2/3)O3,Nd-doped,broad bandwidth emission
更新于2025-09-11 14:15:04
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Broadband and high uniformity Y junction optical beam splitter with multimode tapered branch
摘要： A high uniformity and broad bandwidth Y junction optical beam splitter is proposed and analyzed in this paper based on silicon-on-insulator platform. By replacing the uniform branch with the multimode tapered branch, the bandwidth and the power uniformity of two output ports are improved prominently. Furthermore, the sensitivity to fabrication accuracy is reduced by widening the splitting angle. The simulation and the experimental results confirm that the bandwidth is larger than 100nm, the power uniformity of two output ports is enhanced 4 dB, whereas the insertion loss is less than 0.6dB and the return loss is larger than 26dB, respectively.
关键词： Multimode,Beam splitter,Broad bandwidth,High uniformity,Tapered branch
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland, New Zealand (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Broadening the Bandwidth of the Electromagnetic Metamaterial Absorber
摘要： In this paper, we will first review the application of metamaterial concept to design electromagnetic wave absorber and discuss its limitation on absorption bandwidth. Then we will show several approaches to expand the working bandwidth of metamaterial absorber including the employment of multi-resonator meta-atoms, adjusting the loss in the meta-atom resonance, as well as utilizing metasurface in the Salisbury screen design. Various design examples will be discussed that verified the feasibility of these approaches.
关键词： metasurface,metamaterial,broad bandwidth,absorber
更新于2025-09-04 15:30:14