Equivalent Representations of Nonuniform Transmission Lines Based on the Extended Kuroda's Identity

Kuroda's identity may be extended to circuits consisting of lumped reactance elements and nonuniform transmission lines. It is shown that these circuits are equivalent to circuits consisting of cascade connections of nonuniform transmission lines whose characteristic impedance distributions are different from original ones, lumped reactance elements, and ideal transformers. If a characteristic impedance distribution W(x) of an original nonuniform transmission line is given, a characteristic impedance distribution Z(x) of a transformed nonuniform transmission line may be uniquely obtained using W(x). Moreover, by using these equivalent transformations, network functions of these transformed nonuniform transmission lines can he derived exactly.     

使用直角棱镜耦合器的新方法

利用直角棱镜耦合器,实现了同时激励波导模的传输条纹和m-线,从而使它兼有对称棱镜耦合器的耦合特性。进行了理论分析,并给出测试方法及测量结果。     

Transmission line analysis of aperture-coupled microstrip antenna

The authors present an original analysis of a slot-coupled microstrip antenna. The transmission line model uses previous expressions of conductance and susceptance due to the fringing fields near the edges of the patch; moreover, a simple interpretation of the different impedance transformations is given. Results based on the transmission line model are compared with other theoretical analyses (cavity model, moment method) and measurements.<>     

Introduction of radiation losses in the time domain transmission line method

Because the transmission line method only allows to study the propagation of a pure tem mode along a line, all radiation phenomena are neglected. These phenomena become important when lines have discontinuities, then in this case radiating losses must be included in the theoretical formalism. This paper introduces an original approach to consider radiation of lines and to include them in a time domain transmission line method. Some comparisons with full modes method results validate the method.     

Parallel optical transmitter module using angled fibers and a V-grooved silicon optical bench for VCSEL array

We propose an advanced structure of optical subassembly (OSA) for packaging of the vertical-cavity surface-emitting laser (VCSEL) array, using (111) facet mirror of the V-groove ends formed in a silicon optical bench (SiOB) and angled fiber apertures. The feature of our OSA can provide a low optical crosstalk between neighboring channels, a low feedback reflection, and a large misalignment tolerance along the V-groove. We describe the optimized design of fiber angle, VCSEL position, and fiber position. The fabricated OSA structure consists of 12 channels of angled fiber array, 54.7/spl deg/ V-grooves, Au-coated mirrors on (111) end facet of the V-grooves, and flip-chip-bonded VCSEL array on a SiOB. In this structure, the beam emitted from the VCSEL is deflected at the 54.7/spl deg/ mirror of (111) end facet and propagated into the angled fiber. The angled fiber array was polished by 57/spl deg/. Fabricated OSAs showed a coupling efficiency of 30%-50% that is 25 times larger than that obtained from an OSA with a vertically flat fiber array. Our OSA showed large misalignment tolerance of about 90 /spl mu/m along the longitudinal direction in the V-groove. We fabricated a parallel optical transmitter module using the OSA and demonstrated 12 channels /spl times/2.5 Gb/s data transmission with a clear eye diagram.     

基于OTDR技术的高压输电导线断股和损伤检测

为了保证高压输电线路的正常运行,及时准确地 对输电导线的断股、损伤进行检测,提出了一种应用光 时域反射仪(OTDR)技术对输电导线断股、损伤进行分布式光纤传感检测的方法。基于OTDR技 术搭建了利用钢管模拟输电导线的模拟损伤试验系统,进行了高压输电导线断股、损伤 实物试验。高 压输电导线断股、损伤模拟试验及实物试验的结果表明,应用OTDR技术可以有效地识别出高 压输电导线的断股、损伤,并能够对损伤部位进行精确地定位。     

Signal restoration after transmission through a nonuniform LCRGline

In the present paper, signal restoration after transmission through a nonuniform LCRG line is treated by means of a compact Green function approach. These Green functions are characteristic of the nonuniform line and independent of the incident signal. The compact Green functions map the signal which is received after transmission through a nonuniform LCRG line to split components of the voltage at an arbitrary point on the nonuniform line. Partial differential equations for the compact Green functions are derived together with initial, boundary and jump conditions. A convolution integral with the compact Green function as the kernel is used to restore the original signal. Numerical results for the compact Green functions and for the restored signal are presented. It is noted that for transmission lines with considerable losses, good restoration can be obtained instantaneously by means of a simple RC circuit     

Planar excitation of Goubau Transmission Lines for THz BioMEMS

We propose and demonstrate an original planar excitation of a single wire transmission line also known as Goubau-Line (G-Line). The excitation is based on an electromagnetic transition between a coplanar waveguide and the desired G-line in a planar configuration. We present some characteristics for this line such as its electromagnetic spatial distribution, its velocity, and results in the frequency domain analysis for the transitions. We will also show some results concerning the shape of the G-line and its influence on the transmission level. From these results, we show that there is a great interest for these structures in the field of biological characterization.     

Huygens and the computer-a powerful alliance in numericalelectromagnetics

A time domain technique based on equivalent transmission line interconnections, referred to as the transmission line matrix model (TLM), is presented. The author retraces the history of TLM, from the original concepts of Huygens to the pioneering work of Peter B. Johns, and on to the latest developments in TLM modeling. The most important two-dimensional and three-dimensional TLM algorithms are explained, and new concepts in time-domain representation of frequency-dispersive boundaries are discussed. Some typical applications are described     

Frequency agile slot-fed patch antenna

The authors present an original application of a slot-fed patch antenna. Voltage controlled tuning varactors are connected across the radiating edges of the patch antenna and the resonant frequency can be adjusted in a large frequency band (up to 1 GHz) while the impedance matching remains good. Results based on the transmission line model are compared with measurements     

Equivalent Transformations for Mixed-Lumped and Multiconductor Coupled Circuits

Distributed circuits consisting of a cascade connection of m -port stab circuits and multiconductor coupled transmission lines are equivalent to ones consisting of cascade connections of multiconductor coupled transmission lines whose characteristic impedances are different from original ones, m-port stub circuits, and an m-port ideal transformer bank. Because of the reciprocity of the circuit, values of transformer ratio must be identified. In the special case of a one conductor transmission line, these equivalent transformations are equivalent to Kuroda's identities. These extended equivalent transformations may be applied to mixed-lumped and multiconductor coupled circuits. By using these equivalent transformations, equivalent circuits and exact network functions of multiconductor nonuniform coupled transmission lines can be obtained.     

通过无线商话保障语音专线的应用研究

通过介绍无线商话原理及集团语音专线网络现状,对于因严重传输故障或客户端故障等原因造成的短时间内无法恢复的集团语音专线客户,提出了使用无线商话进行应急保障通信的方案。该方案能确保客户使用无线商话可以进行正常呼叫/被叫,且主叫显示原集团外线号码,外界拨打原号码能转接到无线商话上来。最后,还以具体的测试案例验证了该方案的可行性。     

Conductor geometry independence of phase velocity in TEM-modetransmission lines

Based on Caratheodory's (1952) generalization of the Riemann mapping theorem, it is shown that a proof is possible for the conductor geometry independence of phase velocity in transverse electromagnetic (TEM)-mode transmission lines. Specifically, an effort is made to show that a proof of the invariance of phase velocity with conductor geometry is possible from essentially circuital considerations. The argument implies that it is obvious that any TEM-mode transmission line which consists of two conductors, each of arbitrary section, one totally enclosed within the other, can be transformed into a concentric, right circular, coaxial line. Since solutions of Laplace's equation are invariant under conformal transformation, the inductance and capacitance per unit length of the original and transformed lines must be the same. To establish that fact generally, it remains then only to observe that, for a normal coaxial line, a problem to which there is a simple analytic solution, phase velocity is independent of geometry     

A Method for Synchronous Data Transmission Between Electronic Data Switching Exchanges

In electronic data switching (EDS) exchanges through connection is performed according to the asychronous time-division multiplex principle. In an input code converter, a polarity reversal on a connected subscriber line or trunk is converted into a line address. With the aid of the central control/storage unit this line address is translated into the address of the serving line; via an output code converter a polarity reversal is effected on the respective line and transmitted to the receiving subscriber. The paper describes how the circuitry in the peripheral equipment of the EDS exchange can be reduced if on the trunks between the EDS exchanges line addresses are transmitted instead of single polarity reversals. To enable a good utilization of the transmission link, the addresses are intermediately stored in a parallel-serial converter and provided with an additional time address in order to recover the original instants at which the polarity reversals have occurred. The principle is illustrated by means of an example, and the possibilities of using PCM channels are outlined.     

Angled Split-Ring Artificial Magnetic Conductor for Gain Enhancement in Microstrip Patch Antenna for Wireless Applications

A multiband rectangular microstrip patch antenna integrated with angled split- ring artificial magnetic conducting (AMC) structure is proposed. In order to achieve high gain, directivity and radiation efficiency, an \(3\times 2\) array of proposed angled split-ring patches which has multiple in-phase reflection phase characteristics at S-band (2–4 GHz) is presented as a reflector. A rectangular microstrip patch antenna integrated with the proposed angled split-ring AMC is fabricated, tested and its parameters are compared with the microstrip patch antenna backed with a flat metal sheet, and microstrip patch antenna integrated with conventional split-ring AMC structure. The presence of high scattered field amplitude between the angled arms lead to improved radiation characteristics and make the antenna more suitable for real-time wireless applications. The antenna attains 2.138 dBi increment in gain and 1.87 dBi increment in directivity when it is backed with the proposed angled split-ring artificial magnetic conducting structure instead of a flat metal sheet. A good pact is obtained between the simulated and the measured results.     

一种六轴机器人在雷管装填药剂传送、分发与加药过程中的应用与实践

雷管装填生产线原装药机加药设备5杯药剂的抓取、传送与分发采用直线模组进行,其在使用过程中存在报警频繁、撒漏药严重、故障率较高等问题,给生产作业带来了较大的安全风险。为从根本上解决该问题,可选用技术更加成熟可靠的六轴机器人替换原有直线模组,实现药杯的抓取、传送、分发与加药,六轴机器人具有可靠性高、重复定位精准、整套设备占地面积小、空间布局简洁等特点,实用性较强。     

External cavity semiconductor laser comprising brewster-angled rectangular core fibre

A GaInAsP semiconductor laser diode, with one of its facets Brewster angled was coupled to a Brewster angled rectangular core fibre to obtain an external cavity. Very good coupling efficiency and a high degree of polarisation of the output beam has been obtained.<>     

Even-Odd Modes of a New Transmission Line Based on Semi-Open Dielectric Slab

An original transmission line based on a planar waveguide splitter with central magnetic-dielectric filling is considered. A rigorous electrodynamics model is presented for calculating propagation parameters of hybrid even-odd eigenmodes. It was determined that the physics of the wave processes of the line for these modes is identical to the physics of open structures, though the structure geometry has semi-open character. Numerical experiments prove that new line is very promising for different millimeter wave applications, such as antennae and three-dimensional integrated circuits (TDIC).     

Efficient estimation of sensitivities in TLM with dielectric discontinuities

We present two novel approaches for efficient estimation of objective function sensitivities related to dielectric discontinuities with time-domain transmission line modelling. Using only two simulations, of the original and adjoint structures, the sensitivities with respect to all parameters are obtained. The first approach utilizes an approximation of the adjoint problem. It adapts a recent approach that handles perfectly conducting discontinuities. The second approach exploits the analytic dependence of the nodal scattering matrix on the material properties. The adjoint problem is exact for this case. Our approaches are illustrated through examples involving waveguide dielectric discontinuities.     

Even Modes of a New Transmission Line Based on Semi–Open Dielectric Rode

An original transmission line based on a planar waveguide splitter with central dielectric filling is proposed. A rigorous electrodynamics model is presented for calculating propagation and attenuation parameters of even eigenmodes. The presence of the lowest quasi–H wave having low dissipation loses was detected in the spectrum of hybrid modes. Numerical experiments prove that new line is very promising for different millimeter wave applications, such as antennae and three-dimensional integrated circuits (TDIC).