Millimeter-Wave Oscillators Using Image-Line or Microstrip Waveguides (Short Paper)

A low-cost Gunn oscillator using a coaxial cavity coupled into either dielectric image guide or microstrip line has been developed. A unique feature is the broad frequency range off mechanical tunability of 10 to 11 GHz centered around 56 GHz. This range of tunability is beyond the range of standard metal waveguide cavities. Power levels up to 43 mW have been observed in image-line structures and 20 mW for microstrip lines. The construction allows an easy and quick replacement of diodes, when necessary hence, the structure is easily modified to operate in different ranges.     

加载短路钉微带天线的理论分析

从微带天线腔模法出发,结合叠加原理,提出了加载短路钉微带天线中,同轴馈线内部导线和加载的短路钉上电流比的概念。并利用此概念来分析加载短路钉微带天线内部的电磁场分布和谐振特性、阻抗特性以及辐射特性等。本文给出了加载单个短路钉矩形微带天线的分析,并将本文结果和Zeland软件的仿真结果进行对比,加载短路钉可以以较小天线尺寸实现较低谐振频率,验证了本文方法的有效性。     

Some Aspects of Beam Waveguides for Long Distance Transmission at Optical Frequencies

Two types of beam waveguides are discussed in this paper, the iris-type and the lens-type. Both appear applicable to guided long distance transmission of light with theoretical losses of less than 1 db/km. However, there are problems concerning their practicability which require experimental investigation. Such problems are the alignment of the irises or the lenses, the effects of turbulence and stratification of air along the light path, and the required tolerance in the construction of the lenses. Since the lens-type guide offers a simple possibility for compensating misalignments, an experimental waveguide of this type has been constructed, having a length of approximately 1 km and comprising 10 iterations. The light path is enclosed by a 4 inch aluminum pipe which is supported within a 6 inch aluminum pipe. The first series of experiments which is reported in this paper indicated that there are no serious alignment problems. However, it was found that the effects of turbulence and air stratification are usually very severe and it appears necessary to provide an evacuated light path to obtain constant transmission conditions. It was also found that the available lenses add considerably higher iteration loss than expected. This increased loss was primarily caused by inadequate surface coating. A theoretical study of beam propagation in a misaligned lens-type guide is included in the Appendix.     

Si基微纳集成光波导的理论设计

提出了一种宽度从微米到亚微米、深亚微米、再到纳米级渐变的微纳集成结构光波导，并通过理论分析和模拟计算得到了基于Si基半导体材料的微纳集成光波导参数. 其制作工艺非常简单，插入损耗在1～2.5dB之间. 这种微纳集成光波导不但可解决芯径为10μm的单模光纤与纳米量级的光子晶体波导器件间的光对接、耦合和互连等难题，还可缩小光波导器件芯片的单元尺寸，有利于提高器件的集成度. 为光电子器件向纳米光子集成方向的发展提供了新途径，为新一代全光通信用微纳新原理光电子器件及功能集成的发展提供了新思路.     

Si基微纳集成光波导的理论设计

提出了一种宽度从微米到亚微米、深亚微米、再到纳米级渐变的微纳集成结构光波导,并通过理论分析和模拟计算得到了基于Si基半导体材料的微纳集成光波导参数.其制作工艺非常简单,插入损耗在1～2.5dB之间.这种微纳集成光波导不但可解决芯径为10μm的单模光纤与纳米量级的光子晶体波导器件间的光对接、耦合和互连等难题,还可缩小光波导器件芯片的单元尺寸,有利于提高器件的集成度.为光电子器件向纳米光子集成方向的发展提供了新途径,为新一代全光通信用微纳新原理光电子器件及功能集成的发展提供了新思路.     

Si基微纳集成光波导的理论设计

提出了一种宽度从微米到亚微米、深亚微米、再到纳米级渐变的微纳集成结构光波导,并通过理论分析和模拟计算得到了基于Si基半导体材料的微纳集成光波导参数.其制作工艺非常简单,插入损耗在1～2.5dB之间.这种微纳集成光波导不但可解决芯径为10μm的单模光纤与纳米量级的光子晶体波导器件间的光对接、耦合和互连等难题,还可缩小光波导器件芯片的单元尺寸,有利于提高器件的集成度.为光电子器件向纳米光子集成方向的发展提供了新途径,为新一代全光通信用微纳新原理光电子器件及功能集成的发展提供了新思路.     

Theoretical and Experimental Investigation of Asymmetric Coplanar Waveguides (Short Papers)

Conformal mapping techniques are used to obtain analytic closed-form expressions for the characteristic impedance and the relative effective dielectric constant of asymmetric coplanar waveguide with infinite or finite dielectric thickness. The line asymmetry leads to a decrease of its characteristic impedance and to an increase of its relative effective dielectric constant. Six asymmetric coplanar waveguides are realized and their characteristic impedances are measured using time-domain reflectometry techniques. The experimental results show very good agreement with the theoretical ones.     

Theoretical Investigation of the Input Impedance of Gap-Coupled Circular Microstrip Patch Antennas

In this paper, we have explored a simple theoretical input impedance computation technique for the two gap-coupled circular microstrip patch antennas by using circuit theory approach. The frequency characteristics of the input impedance of the two gap-coupled circular microstrip patch antennas with the gap-distance between the feed patch and parasitic patch is analyzed and simulated. The effect of feed location in the feed patch on the input impedance of proposed antenna is also studied. The theoretical results are compared with the simulated results as well as other reported literature. The simulation has been performed by using a method-of-moment based commercially available simulator IE3D.     

Theoretical Results for the Elliptic Microstrip Resonator (Short papers)

A mode chart and a general expression for the unloaded quality factor of an elliptic microstrip resonator operating in transverse or radial TM modes are presented.     

多短路针加载小型微带贴片天线的理论分析

与单短路针加载微带贴片天线相比，多短路针加载微带贴片天线具有较低的输入阻抗和较宽的频带。本文提出了多短路针加载微带贴片天线谐振频率、输入阻抗及回波损耗的计算方法，给出了相应的计算公式，并用这些公式对具体天线进行了计算，给出了计算结果，分析了天线谐振频率随第2根短路针位置和直径的变化规律。     

PID Self-Tuners: Some Theoretical and Practical Aspects

The appearance in the market of off-the-shelf PID self-tuning (PID/ST) controllers (see Cont. Eng., Oct. 1981) reflects the industry's need to satisfy increasingly stringent control objectives which can only be attained with adaptive algorithms. Further studies on the relatively mature adaptive control theory must be directed toward providing the field engineer with the fundamentals required to utilize this algorithm confidently and profitably. It is in this sense that the study of an adaptive version of the ubiquitous PID controller (with its unquestionably appealing characteristics) must be encouraged. This paper reviews the work done on PID/ST design, the major ideas are briefly discussed, and some specific algorithms presented. The performance of various PID/ST's is illustrated by simulated examples.     

Theoretical Study of Directional Emission Enhancement From Photonic Crystal Waveguides With Tapered Exits

We utilize an approach based on the idea of tapering waveguide exits to increase the directional emission of the light waves emitted from photonic crystal waveguides. It is shown that the enhancement of the directional beaming can be achieved under certain tapered configurations due to the interference pattern created at the exit of the waveguide. The output radiation profile is observed with the finite-difference time-domain method and a 75% reduction in the divergence angle of the out-coupled beam is achieved with the modified waveguide ends.      

毫米波有源柱面共形微带阵列天线的理论与实验研究

本文介绍了一种新型Ｋａ波段毫米波有源柱面共形微带阵列天线,实现了振荡器与天馈系统的单片集成,并应用圆柱坐系下的时域有限差分法对该阵列天线进行了计算和理论分析,得到了令人满意的理论和实验结果。     

Scattering by Material and Conducting Bodies Inside Waveguides, Part I: Theoretical Formulations

A general theoretical formulation of the problem of scattering by material and conducting bodies inside homogeneously filled waveguides is presented. It is based on a reformulation of the existing techniques for free-space scattering in order to adapt them for scattering inside waveguides. This gives rise to two basic alternatives. The first is the volume integral equation formulation (VIEF) and the second is the surface integral equation formulation (SIEF).     

全硅大断面脊形光波导传播特性的理论分析及实验结果

对当前硅光集成的研究焦点－制备大断面单模脊形光波导的单模条件，用有效折射率法进行分析，也计算了传播常数等性能参数。结果表明，有效折射率法有方法简明、结论确切的优点。它能同时给出单模区、多模区及截止区的条件，已有效指导了ＳＩＭＯＸ及ｎ／ｎ＋外延型两种单模脊形硅光波导的制备。文中最后给出了实验结果。     

Acoustic Surface Waveguides and Comparisons with Optical Waveguides

An overview is presented first of the various types of waveguides for acoustic surface waves which have been studied theoretically and experimentally. Many of these waveguides resemble certain waveguiding structures proposed recently for use in integrated and fiber optics. The similarities and differences between corresponding waveguiding structures in the two different fields are then discussed from the standpoints of their properties and their mechanisms of operation.     

硅基SiO2光波导

在硅基上通过氢氧焰淀积的SiO2,厚度达到了20μm;通过掺Ge增加芯层的折射率,折射率比小于1%,并可调;用反应离子刻蚀工艺对波导的芯层进行刻蚀,刻蚀深度为6μm,刻蚀深宽比大于10;波导传输损耗小于0.6dB/cm(λ=1.55μm),并对波导的损耗机理和测试进行了分析与研究.另外,为实现光纤与波导的耦合,结合微电子机械系统技术,在波导基片上制作了光纤对准V形槽.     

Composite Dielectric Waveguides

Composite dielectric waveguides, or a class of dielectric waveguides made of a few dielectric materials, are described. A composite circular dielectric waveguide (CCDW) is treated with the the point-matching method. Computed values of the propagation constant of the CCDW are compared with those of the homogeneous circular dielectric waveguides (HCDW). Microwave experiments carried out to comfirm the theory are discribed.     

Microstrip antennas

Microstrip antennas have been one of the most innovative topics in antenna theory and design in recent years, and are increasingly finding application in a wide range of modern microwave systems. This paper begins with a brief overview of the basic characteristics of microstrip antennas, and then concentrates on the most significant developments in microstrip antenna technology that have been made in the last several years. Emphasis is on new antenna configurations for improved electrical performance and manufacturability and on advances in the analytical modeling of microstrip antennas and arrays     

Coupled EBG Waveguides

Journal of Communications Technology and Electronics - Characteristics of eigenwaves of two coupled EBG waveguides in an electromagnetic crystal are studied. Two variants of distributed coupling...