L波段小型化同轴-共面波导定向耦合器

设计了一种适用于L波段高功率微波辐射场测量的同轴型定向耦合器。分别选择同轴线和金属底板共面波导（CBCPW）作为主副传输线,减小定向耦合器横截面积;利用小孔耦合理论和微元法对耦合结构进行理论分析,选择连续渐变的菱形耦合缝隙,缩短定向耦合器长度;采用数值模拟的方法对耦合器结构进行优化,并对其性能参数进行实验测试,结果表明, 在1~2 GHz频带范围内耦合度约为47 dB,方向性大于17 dB。     

紧凑型菱形缝隙V波段过模圆波导选模耦合器

设计了一种用于测量V波段过模高功率毫米波源在线功率的选模耦合器。利用小孔耦合理论和微元法对菱形耦合缝隙进行了理论分析，采用两组相同的菱形耦合缝隙实现选模功能，缩短了耦合器长度，增加了工作带宽。采用数值模拟的方法对耦合器结构进行优化设计，模拟结果表明:在60 GHz频点处，TM01模耦合度约为50 dB，TM02模耦合度仅为75 dB，对TM02模的抑制度为25 dB；在500 MHz带宽内对TM02模的抑制度大于15 dB，1 GHz带宽内的抑制度大于10 dB，可满足工作于TM01模的V波段高功率毫米波测试需求。同时针对工作于高次模TM0n（n=2,3,4,）的器件设计了可抑制TM01模的耦合器，为高次模工作的高功率毫米波器件的在线功率测量和模式诊断提供了技术方案。     

SOI通道转换型多模干涉耦合器的研究

设计和制作了基于SOI的通道转换型多模干涉耦合器。用二维BPM方法分析了耦合器的性能与多模波导宽度和长度的依赖关系.制作出的耦合器能实现良好的通道转换,器件的功率转换比为73,附加损耗为2.2 dB.提高器件制作的精度将能进一步改善耦合器的性能.     

A MEMS Tunable Optical Ring Resonator Filter

In this work, a new architecture for a ring resonator tunable optical filter is proposed. In this architecture, two rings are connected to each other by a directional coupler and tuning is achieved through the control of the separation between the coupler two parallel guides using a micro-electro-mechanical systems (MEMS) actuator. The optical performance of the filter is tested using the FDTD and an analytical model is developed to predict its performances. A good agreement between the analytical and numerical results is obtained. The MEMS design is also presented and verified using an finite element method (FEM) analysis.     

三芯非线性光纤耦合器中的短脉冲光开关

利用变分法研究三芯非线性光纤耦合器中的短脉冲光开关,解析分析线性三耦合非线性Schr?dinger方程的结果与数值模拟符合得很好.并且得到在非线性光纤耦合器中孤子的耦合长度和开关阈值,与连续波情况和两芯光纤耦合器的结果不同. 关键词： 光纤耦合器 光开关 耦合长度 开关阈值     

220GHz三级串联交错双栅慢波结构

提出了一种220 GHz三级串联的交错双栅行波管结构,针对影响整体传输性能的核心部件——输入输出耦合器进行了详细分析,并以此为基础设计了串联交错双栅慢波结构。通过数值模拟分析,确定了一种由齿深渐变光栅和半圆同心弯头组成的新型输出输入耦合结构。整管粒子仿真结果显示慢波结构内部没有出现振荡现象,且在220GHz达到了30dB增益,3dB带宽达到23GHz,有效改善了该类串联结构由于多个电子注加载通道造成的行波管传输特性下降问题。     

Coupler design for an L-band electron linac

The RF coupler is a key component for an accelerating structure which is the most important component for a linac. In order to feed microwave power into the accelerating cavities effectively, the coupler has to be well matched with the feeding waveguide. In this paper, an electron linac coupler was designed, constructed and tested. A numerical simulation method based on the Kyhl's method was employed to search for the optimal dimensions of the coupler. The frequency and the coupling coefficient as a function of the coupler dimensions were also calculated. The results fitted the Kyhl's method simulation results well and gave tolerances of the coupler. The coupler was brazed to the accelerating cavities and it was cold-tested and hot-tested. The experimental results were consistent with the numerical simulation results.     

W波段回旋行波管输入输出段的改进设计

在回旋行波放大器的设计中,输入输出段的性能直接影响到整管输出功率、效率及增益。设计了一种采用渐变过渡段的输入耦合器来减少电子注在前端的截获,而且略微地提高了耦合特性,有效带宽达到4.06 GHz。采用二级切比雪夫渐变波导作为输出结构的耦合输出段,从仿真结果得到,在整个工作频段内,该结构中TE01工作模式的反射低于-20 dB,TE01模向杂模TE02和TE03的耦合分别在-20 dB和-30 dB以下。     

快速优化折叠波导器件中矩形过渡结构的理论方法（英）

本文推导了基于模式耦合理论的方程组,用于加快和简化折叠波导器件中矩形过渡结构的设计过程。作为功率耦合结构的一个重要组成部分,两种常用的结构将被考虑用来匹配折叠波导慢波结构的矩形波导TE10模式和标准输出矩形波导中的TE10模式。通过比较发现,在同样的反射水平下,锥形过渡结构比阶梯过渡结构长得多,但同时前者却自然具有更快的带宽和对结构误差不敏感的特性。作为算例,设计了220 GHz折叠波导返波管中可能用到的阶梯过渡结构和锥形过渡结构,并进行了误差分析。设计过程中用到的理论方法最终用数值模拟的方法进行了验证,取得了很好的一致性。基于该高精度理论方法的设计耗时不过几分钟。     

Analysis on skin-effect of a polymer shielded push–pull directional coupler electro-optic switch

By using the extended point-matching method, coupled mode theory, and electro-optic modulation theory, design and optimization are carried out for a polymer shielded push–pull directional coupler electro-optic switch. A novel technique and the relative formulas are presented for analyzing the influences of the skin-effect on the microwave characteristic parameters and the switching performances. Simulation results show that the voltages of the cross- and bar-states are 0 and ±2.93 V, respectively, and the coupling length is 4.139 mm. Considering the influences of the skin-effect, the cutoff switching frequency is 172 GHz, the insertion loss is in the range of 1.920–1.975 dB, the crosstalk is less than ?20 dB, and the switching time is 31.18–31.40 ps within the range of the switching frequency from 0.72 to 172 GHz. The designed switch exhibits superior characteristics including good impedance match, low switching voltage, and high cutoff switching frequency.     

Metal mesh couplers using evanescent waves at millimeter and submillimeter wavelengths

In this paper we introduce a metal mesh evanescent wave coupler that makes use of evanescent wave coupling between a metal mesh and a dielectric plate, as a quasi-optical component for millimeter and submillimeter wavelengths. The transmission properties of this type of couplers have been investigated experimentally and theoretically for both capacitive and inductive metal meshes in the frequency range from 40 GHz to 60 GHz. The transmittance of a capacitive metal mesh evanescent wave coupler can be adjusted more than 70% by changing the spacing between the capacitive mesh and the silicon plate less than 0.15 mm at around 57 GHz.     

RF power coupling for the CSNS DTL

The China Spallation Neutron Source(CSNS)drift tube linac(DTL)consists of four tanks and each tank is fed by a 2.5 MW klystron.Accurate predication of RF coupling between the RF cavity and ports is very important for DTL RF coupler design.An iris-type coupler is chosen to couple the RF power to the DTL accelerating cavity.The physical design of the DTL coupler and the calculations of RF coupling between the cavity and coupler are carried out.The results from the numerical simulations are in excellent agreement with the analytical results.     

Design of a capacitive main power coupler for RF superconducting accelerators

An updated main coupler has been designed for the superconducting accelerator of Free Electron Laser (FEL) project under construction in Peking University. A capacitive structure is chosen for the main coupler. Numerical investigation using CST Microwave Studio demonstrates the cold window part. The other nonstandard structures such as holding rods and antenna are also optimized. The coupler uses a 95% purity Al2O3 ceramic cold window. The VSWR (Vottage Standing Wave Ratio) is 1.02 at 1.3 GHz and the frequency bandwidth is 45 MHz with VSWR<1.1. The electric field intensity is 8.5×10m-2 kV/mm around the window with 20 kW Continuous Wave (CW) transmitted power. The Qext is designed variable from 5×106 to 1×107.     

基于微波工作室的盘荷波导耦合器设计方法

提出了一种新的盘荷波导耦合器数值设计方法; 通过分析Kyhl提出的耦合器调节原理, 将输入阻抗之间的相差关系转换为耦合器输入波导的边界条件关系, 由此 利用Microwave Studio的EigenMode Solver求解本征值问题来实现对耦合器 调谐、调匹配过程的模拟; 并给出一个实例来说明数值计算方法的可行性和可靠性.     

Analysis of the plasmonic power splitter and MUX/DEMUX suitable for photonic integrated circuits

In this paper, the metal-insulator-metal (MIM) plasmonic directional coupler (PDC) with 45° waveguide bends based on surface plasmon polaritons (SPPs) excitation has been analyzed by the finite-difference time-domain (FDTD) numerical method. Effects of the variations of the coupler length and the metal gap thickness on the output powers and the propagation loss at 1550 nm wavelength have been studied. By choosing proper coupler lengths, power splitters with various output power ratios at 1550 nm wavelength and multi/demultiplexers, as some applications of the directional couplers have been proposed and their performances have been simulated.     

GaAs／GaAlAs定向耦合器型行波调制器：1.设计

从理论上重点分析和研究了器件行波电极的微波特性，在半绝缘ＧａＡｓ衬底上设计了具有ｎ＾＋重掺杂外延层和共平面电极的ＧａＡｓ／ＧａＡｌＡｓ定向耦合器型行波调制器，针对实验中发现的行波电极上微波的高传输损耗问题。分析了起因并提出了器件的改进设计方案，从而设计出可达到３５ＧＨｚ带宽的高速调制效应的光波导调制器。     

Ultra-thin and light-weight spoof surface plasmon polariton coupler achieved by broadside coupled split ring resonators

Low profile and light weight are very important for practical applications of a spoof surface plasmon polariton(SSPP)coupler, especially at low frequencies. In this paper, we propose and design an ultra-thin, light-weight SSPP coupler based on broadside coupled split ring resonators(BC-SRRs). The size of BC-SRR can be far less than l/100 and can extremely well control the reflective phases within a subwavelength thickness. Due to the broadside capacitive coupling, the electrical size of BC-SRR is dramatically reduced to guarantee the ultra-thin thickness of the SSPP coupler. The weight of the SSPP coupler is reduced by a low occupation ratio of BC-SRR in the unit cell volume. As an example, a C-band SSPP coupler composed of phase gradient BC-SRRs is designed, fabricated, and measured. Due to the ultra-small size and low occupation ratio of BC-SRRs, the thickness of the coupler is l/12 and the surface density is only 0.98 kg/m~2. Both simulation and experiment results verify that the coupler can achieve high-efficiency SPP coupling at 5.27 GHz under normal incidence.     

平面光波导结构的FDTD分析

将各向异性理想匹配层(APML)吸收边界条件用于平面光波导结构的时域有限差分法(FDTD)分析中,导出了APML媒质中适用于角域和边缘的通用差分方程,并对平行介质带定向耦合器进行了数值模拟和验证,所得数值解与解析解非常一致.该方法可用于任意复杂结构的平面光波导的计算机辅助设计与分析.     

W波段TE02模式回旋行波管带宽输入耦合器设计

输入耦合器是回旋行波管的重要组成部分之一,其作用是将矩形波导TE₁₀模式的信号,通过模式变换结构转换为回旋放大器件中的模式,输入耦合器性能的优劣直接影响了回旋管整管的带宽等性能。通过对W波段TE₀₂模式回旋行波管的输入耦合器进行理论分析,指出影响主模传输损耗的一个因素是杂模的崛起使主模的传输系数降低,利用仿真软件进行仿真,通过优化耦合孔的尺寸,抑制杂模的产生,将损耗从3.9 dB降低到了0.8 dB。根据优化尺寸加工,实际测试,得到3.0 dB带宽7.9 GHz的输入耦合器,与设计符合较好。     

一种用于高功率微波合成的X波段双色板

在数值模拟的基础上,设计了一种用于高功率微波合成的X波段同频带双色板。微波斜45°入射时,该双色板在9 GHz到9.3 GHz内反射效率大于99%,在9.7 GHz到10 GHz内传输效率大于99%,可以用于实现两路高功率微波的同极化合成。利用电磁场全波分析软件,建立了双色板数值模型,分析了该双色板的场增强因子和功率容量问题。