基于硅的阵列波导光栅的理论分析

为了研究平面光波导光栅的理论和设计方法,采用波导模场的高斯近似和有效折射率法对波导进行计算,在不考虑平面波导有效折射率的色散效应和近轴近似条件下,分析了阵列波导光栅近似设计理论,经模拟设计与实际设计参数对比,得到了正确的方法,并简化了计算结果.结果表明,这种近似理论为阵列波导光栅的工程设计提供了一种简单实用的计算方法.     

利用光子晶体波导定向耦合差频产生毫米波

文章利用耦合波理论研究了光子晶体两平行直波导的定向耦合差频特性,得出以频率相近的两单频波入射两波导输入端口时,波导中的光场分布的解析表达式,并采用时域有限差分法计算了耦合波导中的模场分布.计算结果表明:通过波导的耦合作用可以在两平行波导中检测到入射波的差频包络,其时域特性与理论分析相符.提出了利用光子晶体定向耦合波导实现光波-毫米波的转换.     

太赫兹宽谱聚合物波导及其传感应用

利用太赫兹时域光谱系统对三种反谐振波导的太赫兹谱进行了研究, 这三种波导分别是PMMA管型波导, PMMA自支撑结构波导和SiO2管型波导.该研究验证了三种波导的太赫兹传输基于反谐振理论, 并在实验上实现了PMMA自支撑结构波导超过2 THz的宽光谱传输.同时, 对基于反谐振原理的太赫兹物质传感进行了理论和实验分析, 为物质探测提供了一种可行的手段.     

微纳米SiGe-SOI弯曲波导的设计

在绝缘体上硅(Silicon-on-insulator,SOI)材料的基础上,建立了SiGe-SOI微纳米尺寸的光波导结构模型,选取了损耗较小的S型SiGe-SOI弯曲光波导进行设计,并对其直波导和弯曲波导的模场进行了分析。设计中采用保角变换和三维全矢量BPM算法相结合的方法,对SiGe-SOI弯曲光波导进行了弯曲损耗分析,得到了弯曲半径对弯曲损耗的影响,给出了影响微纳米SiGe-SOI弯曲光波导设计的敏感参数。最后根据理论分析的结果,绘制了不同宽度的光波导版图,制作了微纳米SiGe-SOI弯曲光波导,并对其进行了测试分析,最终实验结果与理论分析一致,从而验证了该设计方法和理论分析的正确性。     

环渤海大气波导监测和试验方法

在信息化武器装备海上试验和作战使用中,大气波导会对雷达等电子信息装备产生重要影响。研究了大气波导对海上试验和作战的影响,分析了环渤海海区大气波导试验现状,针对目前大气波导理论研究缺乏严谨的综合海上试验验证的现状,进行了环渤海大气波导监测试验方法研究。根据试验情况和资源优势,提出开展大气波导常规试验和大气波导专项任务试验两类试验。环渤海大气波导监测试验的开展将为充分掌握理解环渤海复杂气象环境、构建贴近实战的试验环境提供理论支撑。     

光波导耦合等效电流理论

本文提出等效电流计算光波导耦合理论。推导证明,近年来发展的平行光波导横向耦合公式及棱镜光波导耦合公式均可统一由等效电流理论得出,同时多模光波导的模式耦合理论也可同样处理得到。本理论应用于光波导耦合问题易于得到普遍的结论。     

波导本征值问题的多极理论分析

本文利用多极理论分析波导本征值问题.给出用多极理论分析波导本征值问题的使用规则和实施方法.实例计算结果表明,用多极理论分析波导本征值问题,不仅具有较高的计算精度,而且可以很方便地应用于波导工程问题的设计与计算,多极理论是一种有效的波导本征值分析方法.     

光波导的微观量子理论

目前流行的光波导理论是建立在麦克斯韦方程基础上的宏观理论。虽然在解决一些波导技术问题方面宏观理论已取得了很大成功,但对一些较基本的问题宏观理论却无能为力。例如光是怎样通过与波导物质相互作用而在波导中传播的,为什么波导导模光的性质与一般光的性质大不相同(如导模光可集中在很小的区域中传播而几乎没有衍射损耗)等等。搞     

新型慢波系统毫米波行波管研究

研究了三种新型的曲折波导慢波系统,分别是曲折双脊波导、脊加载曲折波导和矩形槽加载曲折波导。给出了其高频特性的理论和仿真结果。然后介绍了基于常规曲折波导和脊加载曲折波导慢波系统的Ka 波段行波管的实验结果。     

太赫兹宽谱聚合物波导及其传感应用（英文）

利用太赫兹时域光谱系统对三种反谐振波导的太赫兹谱进行了研究,这三种波导分别是PMMA管型波导,PMMA自支撑结构波导和SiO_2管型波导.该研究验证了三种波导的太赫兹传输基于反谐振理论,并在实验上实现了PMMA自支撑结构波导超过2 THz的宽光谱传输.同时,对基于反谐振原理的太赫兹物质传感进行了理论和实验分析,为物质探测提供了一种可行的手段.     

Diagonal horn integrated with micromachined waveguide forsubmillimetre applications

The feasibility of coupling silicon micromachines rectangular waveguide to a modified diagonal horn antenna using a model at 110 GHz is demonstrated. The antenna patterns obtained are similar to those obtained with a standard diagonal horn. A method of reducing the on-axis cross polarization response of diagonal horns is also presented     

Design Note on a Serrated Choke (Correspondence)

The serrated choke described by Dr. Kiyo Tomiyasu and J. J. Bolus is a very effective device to employ whenever long cuts or gaps are present on the walls of rectangular waveguide. This communication is concerned with the application of a serrated choke to an X-band waveguide ring switch, wherein the waveguide was split longitudinally at opposite corners to form a rotor section and a stator section.     

Corner effects on the mutual impedance between edge slots

An analysis for calculating the mutual impedance between two edge slots in a linear slotted waveguide array is presented. The analysis uses a 90° wedge Green's function to account for the influence of the waveguide corners on the evaluation of the external mutual coupling. A novel asymptotic formula for the 90° wedge Green function's is derived to expedite the numerical analysis for slots with large separation. Numerical results show that the phase of mutual impedance retards linearly with slot separation and the magnitude decays as the separation is increased. However, the mutual impedance of edge slots is larger and decays more slowly than that of longitudinal slots or other slots in a large ground plane. The distinguished characteristics can be attributed to the energy guiding effect of the waveguide corners, which is discovered and verified mathematically and numerically. Also shown in the numerical calculations are the incremental conductances of the individual slots in a linear edge slot array, which are compared, and found to be in good agreement, with the available experimental data     

An efficient full-vectorial finite-element modal analysis ofdielectric waveguides incorporating inhomogeneous elements acrossdielectric discontinuities

A new vectorial finite-element method (FEM) free of spurious modes is proposed for analyzing optical waveguides with sharp corners in the cross section. The method is formulated in terms of the transverse field components H_x and H_y or E_x and E_y , and it explicitly shows the relationships between the semivectorial and the full-vectorial wave equations. In this method, we introduce the distribution concept and an inhomogeneous element to describe the field across the dielectric interface, and the error in the numerical solution caused by the dielectric discontinuity is reduced. We show how the width of such inhomogeneous elements and the number of nodes would affect the numerical result and its convergent rate using the dielectric-loaded rectangular waveguide, the channel waveguide, and the rib waveguide as analysis examples. For the dielectric-loaded rectangular waveguide, we compare our results with the exact solutions. For the rib waveguide, we compare our results with previously published data based on other methods. Also, field convergence near the corners is discussed     

Why are accurate computations of mode fields in rectangulardielectric waveguides difficult?

The electric field of the modes of rectangular dielectric waveguides is known to diverge in the corners of the waveguide. An accurate numerical computation of the vector mode fields for a sample waveguide exhibits clear signs of this divergence. The divergence makes the design of rapidly converging numerical algorithms for vector mode field computations difficult     

Evaluation of attenuation from lossless triangular-finite-element solutions for inhomogeneously filled guiding structures

The numerical evaluation of attenuation from lossless triangular-finite-element solutions for inhomogeneously filled guiding structures is expressed in a convenient computational form. Results obtained for a dielectric-loaded waveguide are found to be highly accurate. The application of the new form to structures containing re-entrant corners is also discussed.     

Variations of Slot Cut and Stub Loaded Square Microstrip Antenna for Circular Polarization

Wireless Personal Communications - Modified technique to produce circular polarization for square, nearly square microstrip antenna using diagonal slots of different shapes, slits, stub at corners...     

Optical Waveguide Films With Two-Layer Skirt-Type Core Structures for Beam Leakage/Scattering Reduction at Tapered Mirrors

Using the self-organized lightwave network (SOLNET) technique, we observed guided beam leakage and scattering at tapered mirrors of core end facets in optical waveguide Alms. The leakage/scattering are caused by the tunneling of guided beams into the cladding film and pattern imperfection of core edge corners. To reduce them, we proposed the two-layer skirt-type core structure, where a core has a layered structure of low-index (LI) part and high-index (HI) part. The LI part located between the HI part and the cladding film prevents guided beams from tunneling into the cladding film. The skirt-type shape of core end facets puts core edge corners away from the guided beam paths. The beam propagation method and the finite-difference time-domain method revealed that the leakage/scattering are reduced in the proposed core structure. Optical waveguide films with the two-layer skirt-type core structure were fabricated by the built-in mask method. Appropriate skirt lengths were found to be around core widths. Guided beams were confined into the HI part to reduce the tunneling into the cladding film.     

Integrated band demultiplexer using waveguide grating routers

We present a novel band demultiplexer design for planar lightwave circuits. It consists of two perfectly sampled waveguide grating routers connected by sets of equal-path-length waveguides separated on one side. Its advantages are compactness, sharp passband corners, and a lack of chromatic dispersion.     

Efficient analysis of general waveguide multi-port junctions using a segmentation technique and hybrid matrix formulations

In this paper a segmentation technique, based on hybrid (admittance and impedance) matrix representations, is proposed for the efficient and accurate analysis of rectangular waveguide multi-port junctions with arbitrarily shaped waveguide access ports. The technique is completely outlined, and a new method for solving the connection of hybrid matrices without intermediate inversions is derived. To validate the theory, results for a magic-T junction and a six-port cross junction are compared with experimental data from literature. The new method proposed is also successfully applied to H- and E-plane T-junctions with rounded corners in the side arms.