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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Broadband Linear Polarization Conversion Metasurface Based on Grounded Vias
摘要： An anisotropic high-impedance surfaces is applied to achieve perfect polarization rotation. Three multiple resonances are generated by electric and magnetic resonances which contributed to bandwidth expansion of the proposed polarization converter. The simulation results showed that maximum conversion ef?ciency is nearly 100% at mentioned three resonance frequencies. Here, 107 % bandwidth with polarization conversion ratio of above 90% is achieved. The proposed polarization conversion unit-cell is examined for oblique incidence, as well. It is observed that the bandwidth of the proposed unit-cell is not sensitive to the non-orthogonal incidence angles up to 40?. This observation veri?es applicability of proposed polarization rotator unit-cell.
关键词： polarization conversion,metasurface,high impedance surface
更新于2025-09-23 15:23:52
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[IEEE 2018 3rd International Conference for Convergence in Technology (I2CT) - Pune (2018.4.6-2018.4.8)] 2018 3rd International Conference for Convergence in Technology (I2CT) - Implementation of Polarization-Conversion in Ring-Resonator and its Application to Design All-Optical NOT Logic Gate
摘要： All-optical NOT logic gate is theoretically described using the concept of polarization-conversion in ring resonator. Conversion of polarization states occurs at very high speed of 0.2 ps and high Q-factor of about 1500 is obtained. The design may used in intensity based all-optical switching as well as in designing of all-optical logic gates. Low pump power of about 40 nW/m is required for such conversion based all-optical gates. Suitability in pumping, refractive index contrast, height-to-width ratio of waveguide and phase-matching condition is necessary to obtain such results.
关键词： ring-resonator,polarization conversion,all-optical switch,FDTD simulation,logic gates
更新于2025-09-23 15:23:52
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Arbitrary Polarization Conversion with a Photonic Crystal Slab
摘要： It is shown that a simple photonic crystal slab structure provides a powerful mechanism for the control of the polarization properties of light. For a lossless system, for a given incident light with any fixed polarization, one can generate arbitrary polarization in the reflected light, as one varies the direction of the incident light. In the lossy system, the capability for arbitrary polarization generation is still preserved for s- or p-polarized incident light. This capability for arbitrary polarization generation closely relates to the nontrivial topological properties of the reflection matrix of the structure and exists over a wide range of frequencies.
关键词： photonic crystals,polarization conversion,Poincaré sphere,Stokes parameters
更新于2025-09-23 15:22:29
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Effects of Spatial Dispersion in Symmetric and Asymmetric Semiconductor Quantum Wells
摘要： Effects of spatial dispersion in quantum wells are discovered and investigated in detail in reflection experiments. We studied oblique incidence of pure s and p polarized light which has been reflected elliptically polarized. The polarization degree of the reflected light is governed by the in-plane photon momentum which is the distinctive feature of the spatial dispersion effects. The effects of spatial dispersion are allowed by symmetry in inversion-asymmetric systems only. Therefore we investigated bulk-inversion asymmetric ZnSe/ZnMgSSe and structure-asymmetric GaAs/AlGaAs and CdZnTe/CdTe/CdMgTe quantum wells. We studied the reflected light polarization state in the vicinity of the heavy- and light-exciton resonances where the spatial dispersion effects are resonantly enhanced.
关键词： semiconductor quantum wells,light polarization conversion,excitons,spatial dispersion
更新于2025-09-23 15:22:29
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - A Way to Realize a Multi-Frequency Polarization Plane Rotator
摘要： In this paper, we propose a simple design of a planar-chiral screen based polarization plane rotator that enables a polarization conversion at two assigned frequency bands simultaneously. The rotator is composed of a pair of conjugated double periodic perforated screens separated by a short distance. Two groups of four rectangular slots are cut along a perimeter of the screen periodical cell. Polarization rotation frequencies are controlled by choosing appropriated dimensions and placements of the slots’ groups. At the same time, we report that even a rotator with equal slots belonging to different (outer or internal) quadruples enables a dual-frequency operation as well.
关键词： optical activity,frequency-selective surface,rotator,polarization conversion
更新于2025-09-23 15:21:21
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A Linear-to-Circular Polarization Conversion Metasurface Based Wideband Aperture Coupled Antenna
摘要： This paper proposes an aperture-coupled antenna with an ultrathin, single-layer metasurface for linear-to-circular (LP–CP) polarization conversion. The unit cell of the metasurface consists of a hexagonal ring surrounded by a square ring printed on both sides of a dielectric substrate for wideband LP-CP conversion. A patch antenna excited by an H-shaped slot aperture uses a 5 × 5 array of the metasurface as a superstrate. Simulated and measured radiation patterns of the proposed antenna are in good agreement. Measured S11 and axial ratio bandwidth of the proposed antenna are 21.5% and 19.23% respectively. Boresight radiation gain is around 10 dBic over 9.5 GHz to 11.5 GHz.
关键词： Circular polarization,Polarization conversion,Metasurface,Aperture coupled antenna,Wideband
更新于2025-09-23 15:19:57
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Broadband high-efficiency cross-polarization conversion and multi-functional wavefront manipulation based on chiral structure metasurface for terahertz wave
摘要： In this paper, a broadband and high-efficient tri-layered chiral structure metasurface (CSM) for linear polarization conversion and multi-functional wavefront manipulation was proposed and investigated numerically in terahertz region. The unit-cell of the proposed CSM consist of two orthogonal metal wires sandwiched with square split-ring resonator (SRR) structure, which can manipulate the polarization and wavefront of the transmitted wave simultaneously. Based on the Fabry-Perot-like cavity-enhanced effect of proposed CSM, broadband and high-efficiency cross-polarization conversion can be achieved. Numerical simulation results indicate that the cross-polarization transmission coefficient is higher than 0.9 from 0.4 THz to 1.0 THz, with a fractional bandwidth of 85.7%. The proposed CSM can achieve complete 2π phase coverage by adjusting the geometric parameters of the unit-cell structure. As a proof of multi-functional wavefront manipulation, anomalous refraction with a wide angle, two kinds of focusing metalenses and vortex beam generation are investigated to verify the multi-functional wavefront manipulation performance of the proposed CSM. Our work provides an effective method of enhancing the performance of transmission-type metasurface and the proposed devices show endless potential in wavefront control and communication applications in terahertz region.
关键词： chiral structure metasurface,linear polarization conversion,terahertz,wavefront manipulation
更新于2025-09-23 15:19:57
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Metamaterials - Devices and Applications || Effects of Dielectric Substrate on Polarization Conversion Using Coupled Metasurfaces With and Without Tunneling
摘要： Dielectric substrates are technologically necessary components of various microwave and optical structures and devices, and may strongly affect their performance. For metasurfaces composed of subwavelength resonators, placing dielectric components in the proximity of resonators can lead to strong modification of subwavelength resonances and related transmission regimes. We focus on the effects exerted by material and geometrical parameters of such a dielectric substrate on linear-to-linear polarization conversion that appears in quasiplanar structures containing two coupled metasurfaces and enabling chirality. It is shown that spectral locations of the polarization conversion resonances and transmission efficiency at these resonances are strongly sensitive to the substrate parameters, whereas the ability of polarization conversion and related asymmetry of transmission can be preserved in wide ranges of parameter variation. The effects of a substrate are considered in detail for the mechanisms with and without tunneling, indicating a route to compact designs of quasiplanar structures for single- and multiband polarization conversion.
关键词： permittivity,subwavelength resonator,polarization conversion,metasurface
更新于2025-09-23 15:19:57
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High-Gain Circularly Polarized Fabry–Pérot Patch Array Antenna with Wideband Low-Radar-Cross-Section Property
摘要： In this paper, we explore the adoption of a chessboard polarization conversion metasurface (CPCM) for constructing a low-radar-cross-section (RCS), high-gain circularly polarized (CP) patch array antenna. The proposed CPCM is used as the polarization conversion metasurfaces’ chessboard configuration, which consists of adjacent two-layer substrates that have three metallic models. Low RCS is achieved by 180° (±30°) reflection phase variations of two adjoining PCMSs. Gain enhancement is achieved by adopting a Fabry–Pérot cavity constituted by a PCM and the antenna’s ground. The antenna with a CPCM that operates at X/Ku band, excited by the feeding network that is rotated sequentially, is measured and fabricated. The patch array antenna impedance bandwidth based on PCM was measured as 3.3 GHz (9.5–12.8 GHz) with a 3-dB axial ratio bandwidth of 11.6% and a high gain of 13.4 dBiC (9.5–12 GHz), more than 2.5 dB higher compared with a patch antenna without a PCM. In addition, the patch array antenna produced a useful wideband RCS decrease in the operational bandwidth from 9 to 13 GHz.
关键词： low radar cross-section,dual patch,polarization conversion metasurface,circularly polarized
更新于2025-09-19 17:15:36
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High-gain polarization conversion metasurface
摘要： A novel analytical method based on the cavity mode theory to design a metasurface (MS) is proposed in this study. We carefully analyzed the phase and amplitude characteristics of the incident wave and transmitted wave, and successfully designed a circular polarization conversion MS by introducing a cutting structure with wider operation bandwidth and higher radiation direction gain compared with that of the original MS. For the measurements, a microstrip antenna operating at 2.4 GHz was used as the source antenna to verify the designed MS. The simulation and measurement results agree well with each other.
关键词： metasurface,amplitude adjustment,phase adjustment,polarization conversion
更新于2025-09-19 17:15:36