- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Design of A Two-Dimensional “T” Shaped Metamaterial with Wideband, Low Loss
摘要： A novel two-dimensional (2D) metamaterial structure with center symmetric "T" shaped unit is designed, fabricated, and measured in this paper. The proposed metamaterial comprises of a 2 × 2 array of area 4.3 mm × 4.3 mm, etched on single side of FR4 substrate. The simulation and measurement show that the novel metamaterial has a double negative range frequency of 20.16–37.47 GHz with an absolute width of 17.31 GHz, relative width of 60.07%, small unit loss of 0.16 dB, and small size of 0.07 λ0 in 2D. Furthermore, the double negative region of the proposed metamaterial operates through K band and Ka band, it can be widely used in satellite communication and broadband digital transmission.
关键词： center symmetric "T" shaped,Two dimensions,low loss,wide band
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - Low-Loss, High-Frequency and Large-Coupling SH SAW Resonators Based on SiN/LiNbO<inf>3</inf>/Si
摘要： Low-loss, high-frequency and large-coupling-coefficient SAW resonators based on SiN/LN/Si are demonstrated in this study. By bonding the high-velocity Si substrate to the sub-wavelength-thick LN layer, the shear-horizontal mode SAW resonator no longer couples with the bulk modes in substrate and the leaky component is effectively eliminated. As the propagation loss is no longer the main concern for the cut angle selection, the ultra-large cut angle can be used to achieve high coupling coefficient (κ2). By carefully designing the SiN/LN/Si structure, the high-frequency and large-κ2 SAW resonators with low loss are achieved. The fabricated SAW resonators show great potential for current and next generation front ends.
关键词： SiN/LN/Si,large coupling coefficient,high frequency,low loss,SAW resonators
更新于2025-09-23 15:22:29
-
Universal Output Characteristics of Single-Mode Operation in Low-Loss Large- <i>V</i> -Number Multimode Waveguide Lasers with Transverse Spatial Hole Burning
摘要： We study the performance limit of single-mode operation in low-loss large-V-number planar waveguide lasers, with transverse spatial hole burning as the dominating mechanism for transverse-mode competition. By introducing normalized variables, we develop a simple semianalytical model to describe the universal output characteristics of single-mode emission before the onset of high-order modes, which can be easily scaled to a wide range of laser configuration parameters. Our model is validated using exact numerical solutions, which show applicability beyond that of the low-loss approximation. Our analysis establishes a minimum criterion of the loss ratio between the fundamental and first higher-order mode for a robust single-mode operation. This criterion is much weaker than that of conventional wisdom based on the pure wave-propagation argument, which we attribute to a resonator enhancement effect. Our universal outcome can be denormalized to establish the relationship between single-mode extraction efficiency and optimum output coupling in a multimode laser with arbitrary modal loss ratios over a wide range of single-pass unsaturated gain and loss.
关键词： single-mode operation,transverse spatial hole burning,multimode waveguide lasers,large-V-number,low-loss
更新于2025-09-23 15:19:57
-
Semiquantitative Atomic Force Microscopy-Infrared Spectroscopy Analysis of Chemical Gradients in Silicone Optical Waveguides
摘要： Crossing losses in silicone optical waveguides are related to the magnitude and spatial extent of the waveguide refractive index gradient. When processing conditions are altered, the refractive index gradient can vary substantially, even when the formulation remains constant. Controlling the refractive index gradient requires control of the concentration of small molecules present within the core and clad layers. Developing a fundamental understanding of how small molecule migration drives changes in crossing loss requires the ability to examine chemical functionality over small length scales, which is a natural fit for atomic force microscopy-infrared spectroscopy (AFM-IR). In this work, AFM-IR spectra from model bilayer stacks are initially examined to understand molecular migration that occurs from heating the core and clad layers. The results of these model studies are then applied to photopatterned waveguide builds, where structure?function relationships are constructed between values of crossing loss and the concentration of C?H and O?H functionalities present in the core and clad layers. Results show that small molecule evaporation and migration are competing processes that need to be controlled to minimize crossing loss.
关键词： migration,silicone resin,low-loss,photopatterned,PTIR,waveguides
更新于2025-09-23 15:19:57
-
Thermally-stable low-loss polymer dielectrics enabled by attaching crosslinkable antioxidant to polypropylene
摘要： Polymer dielectrics with low loss and high-temperature tolerance are extremely desirable as electrical energy storage materials for advanced electronics and electrical power applications. They can allow fast switching rates during power conversion and therefore achieve high power densities without thermal issues. Here we explore polypropylene (PP), the state of the art dielectric polymer, and present an innovative approach to substantially improve the thermal stability and concurrently reduce the dielectric loss of PP. In particular, crosslinkable antioxidant groups, hindered phenol (HP), are incorporated into PP via well-controlled chemical synthesis. The grafted HP can simultaneously serve as radical scavenger and crosslinker, thereby constraining thermally decomposed radicals and charge transport in the synthesized PP-HP copolymer. As a result, the upper-temperature limit of PP-HP is greatly extended to 190 ?C and the electrical loss is even gradually reduced upon thermal annealing. The copolymer after heating under 190 ?C exhibits better dielectric properties than the PP without any thermal treatment. The experimental results indicate that the PP-HP copolymers are promising materials for high temperature, low loss, and high voltage dielectric applications.
关键词： energy storage,crosslinking,hindered phenol antioxidants,functionalized polypropylene,high-temperature low-loss dielectrics,electrical leakage current
更新于2025-09-19 17:13:59
-
Laser crystallized low-loss polycrystalline silicon waveguides
摘要： We report the fabrication of low-loss, low temperature deposited polysilicon waveguides via laser crystallization. The process involves pre-patterning amorphous silicon ?lms to con?ne the thermal energy during the crystallization phase, which helps to control the grain growth and reduce the heat transfer to the surrounding media, making it compatible with CMOS integration. Micro-Raman spectroscopy, Secco etching and X-ray di?raction measurements reveal the high crystalline quality of the processed waveguides with the formation of millimeter long crystal grains. Optical losses as low as 5.3 dB/cm have been measured, indicating their suitability for the development of high-density integrated circuits.
关键词： CMOS integration,low-loss,laser crystallization,polysilicon waveguides,optical losses
更新于2025-09-19 17:13:59
-
Dielectrics for Terahertz Metasurfaces: Material Selection and Fabrication Techniques
摘要： Manipulation of terahertz radiation opens new opportunities that underpin application areas in communication, security, material sensing, and characterization. Metasurfaces employed for terahertz manipulation of phase, amplitude, or polarization of terahertz waves have limitations in radiation efficiency which is attributed to losses in the materials constituting the devices. Metallic resonators-based terahertz devices suffer from high ohmic losses, while dielectric substrates and spacers with high relative permittivity and loss tangent also reduce bandwidth and efficiency. To overcome these issues, a proper choice of low loss and low relative permittivity dielectric layers and substrates can improve field confinement and reduce dissipation. Alternatively, replacing metallic resonators with a moderate relative permittivity dielectric material that supports cavity mode resonances also reduces dissipation due to the absence of conduction current. Herein, an overview of dielectric materials employed as spacers and dielectric resonators is provided, and the fabrication methods employed to realize these devices at the terahertz frequency range are also presented. Material selection guidelines, material-specific and application-specific fabrication quality metrics are outlined, and new techniques are proposed.
关键词： metasurfaces,dielectric spacers,dielectric resonators,low loss dielectrics,terahertz devices
更新于2025-09-19 17:13:59
-
Low-Loss Buried-Heterostructure Optical Waveguide Based on Impurity-Free-Vacancy-Diffusion Quantum Well Intermixing
摘要： A new method for fabricating a high-quality buried-heterostructure optical waveguide using quantum well intermixing (QWI) has been demonstrated. By patterning a SiO2 thin ?lm on top of a multiple quantum well (MQW) heterostructure, rapid thermal annealing (RTA) could induce laterally local QWI, resulting in a bandgap blueshift and a simultaneous decrease in the refractive index. Both lateral bandgap and index engineering could be attained along the MQW plane, which could be used for a buried-heterostructure optical waveguide. Two SiO2 strips with 3, 5 and 7 μm windows were fabricated for waveguide on a 1540 nm InGaAsP MQW sample. A 120 nm blueshift under the SiO2 area was observed, leading to the index contrast of 0.07. Far-?eld optical diffraction measurements were also performed to yield angles of 13.9°, 12.8° and 10.6°. A narrower window resulted in a narrower optical waveguide width and exhibited a larger diffraction angle, suggesting that QWI de?ned the buried optical waveguide. In addition, an electroabsorption modulator was also made by buried waveguide. A ?10 dB low optical insertion loss and a 15 dB high extinction ratio in a 500 μm long waveguide were obtained, indicating that a buried heterostructure could be used for photonic devices and integration applications.
关键词： Quantum well intermixing,buried waveguide,electroabsorption modulator (EAM).,low loss waveguide
更新于2025-09-19 17:13:59
-
3-D-Printed Modified Butler Matrix Based on Gap Waveguide at W-Band for Monopulse Radar
摘要： This article presents the design and fabrication of low-loss, -weight, and -cost, modified Butler matrix in groove gap waveguide technology at W-band, implemented by additive manufacturing. The design, simulations, and measurements of the elements that conform to the modified Butler each of matrix are presented. The proposed modified Butler matrix is asymmetric and oriented to an easy assembly with a radial antenna in order to obtain simultaneous sum and difference patterns for a narrowband radar application. The measured individual components of the modified Butler matrix fit very well with the simulations. As for the full modified Butler matrix, measurements provide a 0.7% bandwidth below ?20 dB for sum and difference ports centered at 94 GHz. The amplitude and phase imbalance are below 1.5 dB and 20?, respectively. This narrow bandwidth is due to the difference in length between input and output ports due to the asymmetry of the design. The total losses of the modified Butler matrix are below 1 dB.
关键词： low profile,distribution network,Additive manufacturing,butler matrix,low cost,W-band,point-to-point communications,low weight,groove gap waveguide (GGW),radar,low loss,monopulse,space debris
更新于2025-09-16 10:30:52
-
Study of an Electromagnetic Wave Transmission Line Based on Coupled Dielectric Resonators
摘要： An analog of an optical waveguide in the form of a chain of metallic nanoparticles has been investigated using modified cylindrical dielectric resonators in the microwave band. Similar to the plasma oscillations in spherical nanoparticles, the two lowest resonances of the dielectric resonator correspond to the dipole and quadrupole oscillatory modes. It is shown that a waveguide consisting of seven resonators exhibits high frequency selective properties and relatively low loss if the resonances of the quadrupole oscillatory modes are used to form its passband. The characteristics of the investigated waveguide remain almost unchanged at its bending by 90°, and the cross section of localization of the main part of the energy propagating in the waveguide is smaller than the electromagnetic wavelength by a factor of five, which approximately corresponds to the optical waveguides based on plasma oscillations in nanoparticles.
关键词： dipole and quadrupole oscillatory modes,frequency selective properties,electromagnetic wave,dielectric resonators,transmission line,low loss,nanoparticles,optical waveguide,microwave band
更新于2025-09-16 10:30:52