Full-Wave Analyses of Coaxial to Waveguide Adapters by the FDTD Method

The finite-difference time-domain (FDTD) method is applied to the full-wave analyses of the electrical properties of millimeter wave coaxial to waveguide adapters. The results are useful for the design of wideband coaxial to waveguide adapter.     

Support Vector Regression Model for Millimeter Wave Transitions

In this paper, we introduce a new method, support vector regression (SVR) method, to model millimeter wave transitions. SVR is based on the structural risk minimization (SRM) principle, which leads to good generalization ability for regression problem. The SVR model can be electromagnetically developed with a set of training data and testing data which produced by the electromagnetic simulation. Two Ka-band millimeter wave transitions, i.e., waveguide to microstrip transition and coaxial to waveguide adapter, are used as examples to validate the method. Experimental results show that the developed SVR models have a good predictive ability, and they are useful for interactive CAD of millimeter wave transitions.     

Artificial Neural Network Models for the Double-Vias in Multilayer Stripline Circuits

Multi-vias is a kind of interconnection largely existing in the multi-chip module (MCM) packages for high-speed digital circuits. In this paper, a multilayer perceptron neural network (MLPNN) is used to model the double-vias in multilayer stripline circuits. The MLPNN is electromagnetically developed with a set of training data that are produced by the full-wave finite-difference time-domain (FDTD) method. One type of the designs of experiments, the central composite technique, is used to allow for a minimum number of FDTD simulations that is needed to be performed.     

Artificial Neural Network Models for the Gap Discontinuities in Stripline Circuits

Gap discontinuities appear in many stripline circuits, such as the multilayer microwave monolithic ICs and the interconnect systems in high-speed digital circuits. In this paper, a multilayer perceptron neural network (MLPNN) is used to model the gap discontinuities in stripline circuits. The MLPNN is electromagnetically developed with a set of training data that are produced by the full-wave finite-difference time-domain (FDTD) method. The full-factor design of experiments is used for determining the size of the training data.     

用于毫米波焦面成像阵的介质加载波导阵元分析

分析了有望用于毫米波成像焦面阵的介质加载波导阵元，采用时域有限差分法(FDTD)计算输入特性，优化了输入基本匹配时的结构尺寸参数，计算该结构参数下的阵元与成像透镜衍射场Airy斑的耦合效率并与其它阵元做了比较。     

基于多层感知器神经网络的波导匹配负载设计

讨论了多层感知器神经网络(MLPNN)在矩形波导终端匹配短负载设计中的应用.网络学习过程采用反向传播算法(BP),并对训练和测试用样本进行随机化,训练过程中加入动量项,网络结构可进行自动调节.对样本进行了线性定标,用定标后的样本训练神经网络,建立系统模型,通过优化神经网络相应参数成功实现了矩形波导H面T型结构的终端短小匹配负载的结构设计.     

同轴型相对论返波管的粒子模拟研究

本文提出和设计了一种Ｘ波段大直径同轴相对论返波管,同时域有限差分法数值计算了器件慢波结构中ＴＭｏｎ模式的色散关系,耦合阻抗,运用粒子模拟程序仿真了器件中波互作用的非线性物理过程,预见了器件输出功率,效率,工作频率,并对器件功率与慢波结构尺寸,电子波束流参数,引导磁场强度之关系进行了优化分析。     

共面波导垂直互连结构的人工神经网络模型

垂直互连是三维微波和毫米波集成电路中的典型结构。本文采用人工神经网络模型模拟屏蔽共面波导的垂直互连结构,由时域有限差分法产生网络的训练和测试样本。训练好的网络同时具有时域有限差分法的精度和人工神经网络的快速性。     

Artificial Neural Network Models for the Bend Discontinuities in Stripline Circuits

Stripline discontinuities are basic elements of many stripline circuits, such as the multilayer microwave monolithic ICs and the interconnect systems in high-speed digital circuits. Bend as one type of the stripline discontinuities will be modeled in this paper. A multilayer perceptron neural network(MLPNN) is used to model the bend discontinuities in stripline circuits. The MLPNN is electromagnetically developed with a set of training data that are produced by the full-wave finite-difference time-domain (FDTD) method. The full-factor design of experiments is used to determine the size of the training data.     

毫米波微带键合金丝互连模型的研究

本文应用神经网络方法、采用FDTD全波分析结果作为训练样本得到了毫米波微带键合金丝互连的参数模型.这个神经网络模型可以指导毫米波集成电路的设计,利用该模型可以得到不同拱高、微带间隙和频率时的电路散射参数.实验测试了键合金丝互连的散射参量并与神经网络模型的结果进行了比较分析.     

Artificial Neural Network Model for the Gap Discontinuity in Shielded Coplanar Waveguide

Fast and accurate component models are essential for the development of three dimensional millimeter wave integrated circuits. In this paper, an accurate and efficient artificial neural network (ANN) model for the gap discontinuity in shielded coplanar waveguide is presented. The ANN model is developed with a set of training data given by the finite-difference time-domain simulation and can be used in the frequency scope of 0≈100GHz.     

A Locally Conformal Algorithm for Handling Curved Metallic Surfaces and Its Application

This paper describes a modified locally conformal algorithm for finite-difference time-domain (FDTD) method. Fields in the entire computational domain are computed by a regular FDTD algorithm except those near curved metallic surfaces, where special techniques proposed in this paper are applied. The computation efficiency of a regular FDTD method is maintained while a high space-resolution is obtained by this new algorithm. To validate the reliability of the algorithm, coaxial continuous transverse stub arrays at millimeter wave Ka-band and microwave X-band are tested, and the simulated results show good agreement with the experimental results from an HP-8510B Network Analyzer and the simulation results from software package HFSS.     

FDTD Simulation for the Focusing Property of Extended Hemispherical Lens as Receiving Antenna

The focusing property of extended hemispherical lens, on which a linearly polarized plane wave is incident normally, is simulated by FDTD method. The focusing process is presented pictorially at different moment. Focal length is obtained and compared with that computed by other method. Good agreement has been found. The coupling between the focused incident wave and a waveguide in the focal plane of the lens is also simulated. The lens is used as antenna at millimeter wavelengths.     

A packaged Schottky diode as detector,harmonic mixer,and harmonic generator in the 25–500 GHz range

This paper describes experimental results obtained with a packaged GaAs Schottky barrier diode in contact with a coaxial connector and placed across waveguides for bands Ka, V, E, W or F. Among the microwave sources used for calibration were 9 carcinotrons in the frequency interval 51–490 GHz. As soon as the frequency F is above the waveguide cut-off frequency, the different characteristics do not depend critically on the waveguide size for V, E, W and F bands. The video detection sensitivity, of several 100 mV/mW at 50 GHz and below, decreases as F^?4 in the range 51–500 GHz. Coupling an X-band centimeter frequency via the coaxial connector and a millimeter frequency via the waveguide permits harmonic mixing in the diode. Between 36 and 490 GHz, the harmonic mixing number varies from 3 up to the very large value 40 with conversion losses from 18 to 88 dB. The minimum detectable signal in the 100 kHz band can be as low as ?90 dBm at 80 GHz. A noticeable millimeter power is available at the waveguide output from injected centimeter power by harmonic generation. Starting for instance with 100 mW around 11.5 GHz, we have measured 0.1 mW at 80 GHz and 0.1 μW at 230 GHz. To illustrate the possibility of creating usable millimeter and submillimeter wave without heavy equipment (such as carcinotrons or millimeter klystron) we report spectroscopic experiments in Rydberg atoms. Resonances have been observed up to 340 GHz by harmonic generation (28th harmonic) from an X-band klystron).     

毫米波矩形介质波导传播特性的FDTD分析

采用ＦＤＴＤ法分析了矩形介质波导的传播特性，与其它方法相比，它不受材料介电常数大小的限制，即使在较高分电常数情况下，也能获得满意的结果；同时作为全波分析方法，ＰＤＴＤ法能方便地求得波导中存在的各个模式的传播常数及其横截面场分布．     

光控矩形介质波导毫米波传播特性的FDTD分析

本文在吴祥应等人(1997)求解半导体中光生载流子分布的基础上,应用时域有限差分(FDTD)法对光控矩形介质波导的传播特性进行分析,并与实验结果作了比较,两者吻合很好.     

基于场分量匹配法的毫米波波导-同轴过渡

基于场分量匹配法研制了毫米波波导-同轴过渡。采用了四级阶梯阻抗变换结构改善转换的阻抗匹配,增加工作带宽,降低回波损耗;并且利用从波导短路面插入同轴探针来实现波导到同轴转换,以达到低插损、宽带宽等目的。最后利用CST仿真软件进行仿真分析和优化设计,并根据仿真设计结果制作出产品,产品测试结果与仿真设计值相符。     

Characterization of three-dimensional open dielectric structuresusing the finite-difference time-domain method

Millimeter and submillimeter wave three-dimensional (3-D) open dielectric structures are characterized using the finite-difference time-domain (FDTD) technique. The use of FDTD method allows for the accurate characterization of these components in a very wide frequency range. The first structure characterized through FDTD for validation purposes is a mm-wave image guide coupler. The derived theoretical results for this structure are compared to experimental data and show good agreement. Following this validation, a sub-mm wave transition from a strip-ridge line to a layered ridge dielectric waveguide (LRDW) in open environment is analyzed, and the effects of parasitic radiation on electrical performance are studied. The transition is found to be very efficient over a wide sub-mm frequency band which makes it useful for a variety of applications. In addition to the transition, a sub-mm wave distributed directional coupler made of the LRDW is extensively studied using the FDTD method as an analysis tool. Furthermore, an iterative procedure based on the FDTD models is used to design a 3-dB coupler with a center frequency of 650 GHz and negligible radiation loss. This successful design shows that the FDTD technique can be used not only as an analysis method, but also as a design tool to provide designs which take into account all high frequency parasitic effects     

超级紧凑V和W波段宽带透明波导窗设计

设计了一种超级紧凑的、可工作于V波段及W波段的毫米波波导窗,它基于低损耗环烯烃共聚物(COC),加工成阶梯结构,放置在波导匹配段中间对称位置,并在两侧连接标准的矩形波导通道,从而具有宽带、透明、易匹配以及机械性能良好等特点.验证了该波导窗在V波段和W波段内的可行性,在回波损耗优于20 dB的情况下,在V波段工作频带为5...     

Design, Fabrication, and Characterization of Novel Vertical Coaxial Transitions for Flip-Chip Interconnects

In this paper, a novel transition design using vertical “coaxial transition” for coplanar waveguide (CPW-to-CPW) flip-chip interconnect is proposed and presented for the first time. The signal continuity is greatly improved since the coaxial-type transition provides more return current paths compared to the conventional transition in the flip-chip structure. The proposed coaxial transition structure shows a real coaxial property from the 3-D electromagnetic wave simulation results. The design rules for the coaxial transition are presented in detail with the key parameters of the coaxial transition structure discussed. For demonstration, the back-to-back flip-chip interconnect structures with the vertical coaxial transitions have been successfully fabricated and characterized. The demonstrated interconnect structure using the coaxial transition exhibits the return loss below 25 dB and the insertion loss within 0.4 dB from dc to 40 GHz. Furthermore, the measurement and simulation results show good agreement. The novel coaxial transition demonstrates excellent interconnect performance for flip-chip interconnects and shows great potential for flip-chip packaging applications at millimeter waves.