Efficient modeling of 3-D photonic crystals for integrated optical devices

We propose a full-wave numerical model of a three-dimensional (3-D) photonic crystal with the absolute photonic bandgap (PBG) centered at /spl lambda//spl sim/1.6 /spl mu/m. The analyzed structure is widely used in integrated optical circuitry. The electromagnetic analysis is performed by using the finite-element method (FEM) and transmission line matrix-integral equation (TLMIE) method. We analyze the reflection properties and compare theoretical results to experimental data. Due to its exact boundary conditions, TLMIE shows much higher accuracy with respect to FEM in the PBG optical band. As a demonstration, we have realized and analyzed a holographic polymer dispersed liquid crystal grating.     

Accurate analysis of H-shaped antenna coupled to microstripfeed-line

An accurate investigation of a microstrip H-shaped antenna is presented, coupled by means of an aperture or via-hole to a microstrip feed-line. The EM analysis is performed by means of the hybrid transmission line matrix-integral equation method. The calculated S-parameters are compared to measured results and to those obtained by the generalised transverse resonance-diffraction method     

Analysis of Microstrip-Like Transmission Lines by Nonuniform Discretization of Integral Equations

The nonuniform discretization of the integral equation on the tangential electromagnetic (EM) field on the boundary surface is proposed as a numerically efficient method to analyze the microstrip-like transmission lines. The calculated results of the propagation constant of the microstrip line based on this method are compared with other published analytical results. Various types of planar striplines are treated by the same formulas. The dominant and higher order modes of shielded microstrip line are discussed and compared with the longitudinal-section electric (LSE) and linear synchronous motor (LSM) modes of a two-medium waveguide.     

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.     

Radiation from the transmission line with an acute bend

The transmission and radiation characteristics at an acute bend of a transmission line are investigated analytically. First, in consideration of the strong coupling to the adjacent conductor, the current distributions are decomposed into even and odd modes. Applying the traveling-wave mode method to these modes, it is shown that transmission characteristics of the line with an acute bend can be easily obtained. The abrupt variation of the voltage near the bend is noted. Next, the discontinuities of the traveling wave currents are regarded as radiating sources and the radiation field from the bend in the transmission line is derived by the summation of fields created by each of the discontinuities. It is found that there exist the electric field component radiating strongly in the directions of propagation of the current and another electric field component radiating strongly into the intermediate direction. Finally, by comparing with the former method and experimental results, the validity of the method is confirmed     

Electromagnetic modes in conical transmission lines withapplication to the linearly tapered slot antenna

A transmission line analysis of the bow-tie antenna and the linearly tapered slot antenna (LTSA) is presented. These structures belong to the class of conical transmission lines defined here in terms of conical coordinates. A complete set of solutions of the Helmholtz equation is obtained exhibiting TE and TM modes. Modal fields are expressed by Lame (1837) and Bessel-Schelkunoff functions. TE and TM eigenmode analysis is particularized to the bow-tie structure. Bow-tie antenna and LTSA are shown to be dual conical transmission lines by the image method and Babinet's principle. The modes of LTSA are calculated on the basis of the results obtained for the bow-tie structure. The radiation pattern of the LTSA is computed as the integral of a closed-form expression of the dyadic Green's function weighted by the modal electric field distribution over the slot aperture. The obtained dominant mode radiation patterns are validated by measurements from the literature. The radiation patterns of the first two-order modes are calculated and compared     

An electromagnetic energy coupler for medical applications

An applicator for coupling electromagnetic (EM) energy into a dielectric material such as tissue is described. The applicator is a section of a surface strip transmission line which has proved to couple the EM energy efficiently and with minimal radiation leakage around the body. It is also small, light, and flat, and hence, suitable for medical applications.     

Radiation characteristics of cavity backed aperture antennas infinite ground plane using the hybrid FEM/MoM technique and geometricaltheory of diffraction

A technique using the hybrid finite element method (FEM)/method of moments (MoM) and geometrical theory of diffraction (GTD) is presented to analyze the radiation characteristics of cavity fed aperture antennas in a finite ground plane. The cavity which excites the aperture is assumed to be fed by a cylindrical transmission line. The electromagnetic (EM) fields inside the cavity are obtained using finite element method (FEM). The EM fields and their normal derivatives required for FEM solution are obtained using: (1) the modal expansion in the feed region and (2) the MoM for the radiating aperture region (assuming an infinite ground plane). The finiteness of the ground plane is taken into account using GTD. The input admittance of open-ended circular, rectangular, and coaxial line radiating into free space through an infinite ground plane are computed and compared with earlier published results. Radiation characteristics of a coaxial cavity-fed circular aperture in a finite rectangular ground plane are verified with experimental results     

A versatile, via terminated electromigration test structure for various stress modes used during fast wafer level reliability (fWLR) testing

A multipurpose electromigration (EM) test structure designed for advanced fast wafer level reliability (WLR) tests is described in this work. It is shown that different failure location and failure modes can be detected electrically by this test structures which is beneficial for early technology development as well as productive in-line monitoring. Highly accelerated WLR tests use the metal self-heating effect for temperature stress acceleration. It is shown here that the design of interconnects with respect to the critical metal line and the periphery of the tested metal line has a large impact on the stress temperature. A carefully designed test structure guarantees the ability to test for different EM failure modes (upstream, downstream). The presented experimental data focuses on the investigation of different process splits.     

Embedded microstrip interconnection lines for gigahertz digitalcircuits

Transmission line structures are needed for the high-performance interconnection lines of GHz integrated circuits (ICs) and multichip modules (MCMs), to minimize undesired electromagnetic wave phenomena and, therefore, to maximize the transmission bandwidth of the interconnection lines. In addition, correct and simple models of the interconnection lines are required for the efficient design and analysis of the circuits containing the interconnection lines. In this paper, we present electrical comparisons of three transmission line structures: conventional metal-insulator-semiconductor (MIS) and the embedded microstrip structures-embedded microstrip (EM) and inverted embedded microstrip (IEM). In addition, we propose closed-form expressions for the embedded microstrip structures EM and IEM and validate the expressions by comparing with empirical results based on S-parameter measurements and subsequent microwave network analysis. Test devices were fabricated using a 1-poly and 3-metal 0.6 μm Si process. The test devices contained the conventional MIS and the two embedded microstrip structures of different sizes. The embedded microstrip structures were shown to carry GHz digital signals with less loss and less dispersion than the conventional MIS line structures. S-parameter measurements of the test devices showed that the embedded microstrip structures could support the quasi-TEM mode propagation at frequencies above 2 GHz. On the other hand, the conventional MIS structure showed slow-wave mode propagation up to 20 GHz. More than 3-dB/mm difference of signal attenuation was observed between the embedded microstrip structures and the conventional MIS structure at 20 GHz. Finally, analytical RLCG transmission line models were developed and shown to agree well with the empirical models deduced from S-parameter measurements     

PCB上微带线的电磁耦合时域建模分析方法

基于时域有限差分方法和传输线方程,结合高效网格建模技术,文中提出了一种高效的时域建模算 法,它能有效解决微带线的电磁耦合建模问题,实现空间电磁场与微带线瞬态响应的同步计算。首先,结合经验公 式,计算得到微带线的单位长度分布参数,构建适用于微带线电磁耦合分析的传输线方程。然后,采用时域有限差 分(Finite-Difference Time-Domain, FDTD)方法,结合非均匀网格技术和自动网格生成技术,仿真得到微带线激励场, 并在每个时间步进上引入传输线方程获得等效分布源项。最后,对传输线方程使用FDTD 的中心差分格式进行离 散,实现微带线及其端接电路上瞬态响应的迭代求解。为了验证时域建模算法的正确性和高效性,通过自由空间和 屏蔽腔内PCB 上微带线电磁耦合的数值模拟,从计算精度和耗时两方面与传统FDTD 方法的计算结果进行了对比。     

1千伏以下的金属球间隙静电放电辐射特性的测量研究

In this study, the characteristics of Electromagnetic (EM) radiation caused by Electrostatic Discharges (ESDs) from metal spheres charged to voltages less than 1 kV are examined experimentally. Our experimental system consists of a pair of spherical elec-trodes of different diameters, a 1-18 GHz-band- width horn antenna and a 20-GHz-bandwidth digitizing oscilloscope. Polarization, waveform duration and peaks of antenna-received voltages from the EM field radiation are measured in order to clarify the EM radiation mechanism. The ratio of the received voltages between the antenna arr-angements of the field polarization parallel and perpendicular to the spark pass is 18 to 20 dB. The polarities of the antenna-received voltages are the same as those of the charge voltages across the gap. Moreover, the waveform duration and the first peaks increase with an increase in the diameters of the spherical electrodes. Consequently, we find that the polarization, waveform duration and first peaks of the EM field radiation can be explained by a dipole antenna structure, which makes the spark part of the spherical electrodes a feeding point on the straight line passing through the centres of the two spheres.     

Regular solution of shielded planar transmission lines

The analysis of shielded transmission lines has been completed using a new method: Regular solution of singular integral equation (RSSIE). Here, an integration procedure is adopted and the uniqueness of the fields is determined by the regularity conditions for the solutions of the singular integral equations at the edges of the metal strips. This leads to more rapid convergence of the series solutions, and enables the analysis of any kind of shielded planar transmission line. It is demonstrated that the results obtained by the proposed method are more accurate than those computed by the spectral domain method (SDM) in comparison with the data measured. In some special cases where the results can exactly be obtained, the proposed method gives more accurate values than those calculated by the SDM. Dominant and higher order modes can be calculated effectively and accurately. The investigation of convergence shows that not only dominant mode but also higher order modes converge rapidly. The computer time required by this proposed method decreases considerably in comparison with SDM     

Analysis of spherical annular microstrip antennas

The spherical annular microstrip antenna is analyzed. The antenna is excited by a coaxial line. The general transmission line model (GTLM) is used to compute the input impedance. The radiating TM₁₂ mode is considered because of its wide band. The effect of the other radiating modes and the nonradiating modes on the TM₁₂ mode is investigated. The effect of different parameters on the input impedance is considered. The radiation patterns are computed using the method of moments     

On the excitation of a circular loop antenna by travelling-and standing-wave current distributions

Presented here is an exact formulation of the electric and magnetic (EM) fields radiated by a circular loop antenna, assuming both travelling- and standing-wave current distributions. By using a differential current element positioned in an azimuthal direction as the starting point, the paper systematically develops the EM fields radiated by the circular loop via a vector potential theory. This approach leads to a general integral representation for the radiation characteristics of the loop antenna where we completely evaluate the resulting expressions, when the excitations of the loop assume travelling- and standing-wave distribution forms. In addition, this paper briefly examines a method to generate approximately such current distributions by coupling the loop to a two- or four-wire transmission line. Furthermore, the paper discusses a graphical representation of the current distribution plotted as a function of frequency or loop size. From the field expressions determined, we derive generalized closed-form results for some important design parameters for the loop antenna. These parameters include the radial component of the Poynting vector, the total power radiated by the loop, the directivity, the radiation resistance, and the effective area and height of the antenna. When we specialize to the important case of uniform current excitation, the exact values of the parameters deduced from the general expressions, are summarized and exhibited in a comprehensive table. This table facilitates the computations of these important physical parameters. Further analysis involving small argument and asymptotic approximations in the residts for the travelling-wave current excitation leads to closed-form expressions in terms of tabulated functions. Numerical results presented, include the fields radiated by the loop when the standing-wave current excitation admits a Fourier series representation. The present approach via potential theory reveals that the fields can be calculated in any arbitrary direction : this is consistent with a previous observation of Knudsen (1951, 1953) who employed a different approach.     

A study on the radiation loss from a bent transmission line

This paper deals with the radiation loss of bent transmission lines in order to determine the most optimal design for a bent line from the standpoint of radiation loss. We have used the method of moments (MoM) for a numerical analysis on the radiation for different structures of bent lines and we have found that the simplest right-angle bend is the best with the least radiation loss. This theoretical expectation was confirmed experimentally     

Coplanar waveguide-fed circularly polarized microstrip antenna

Design of a square microstrip antenna for obtaining circular polarization (CP) radiation using a coplanar waveguide (CPW) feed is presented. This CP design is achieved by insetting a slit to the boundary of the square microstrip patch, which makes possible the splitting of the dominant resonant mode into two near-degenerate orthogonal modes for CP radiation and introducing an inclined slot in the CPW feed line for coupling the electromagnetic (EM) energy of the CPW to the square patch. Good impedance matching for CP operation can be obtained by adjusting the inclined slot length and the tuning-stub length of the CPW feed line. Typical experimental results are presented and discussed     

Applications nouvelles de la matrice des lignes de transmission: Sélection des modes dans les lignes microondes caractérisation des éléments rayonnants

The transmission line matrix method permits modification of the excitation of modes in microlines. This property gives access to phase velocities by synchronisation of excitation and propagating modes. The selection of modes is possible by this synchronisation. Group velocities are deduced from frequency modulation due to geometrical dimensions variation. In another part, two methods of infinited space simulation are proposed. Applications about radiation patterns of the dipole antenna and the half dipole are given. The input impedance and the resonance frequency are calculated for a printed strip dipole.     

双绞线BCI 等效替代强场电磁辐射实验研究

针对低频线缆耦合通道中最常见的双绞线电缆,以比较典型的互连线缆双绞线为研究对象,针对互连系统单端为非线性受试设备的电磁辐射敏感度进行实验研究。对连续波电磁辐射条件下双绞线传输线负载响应进行了理论推导,分析了典型互连系统辐射与注入的等效以及在高场强下的外推条件。对双绞线耦合通道大电流注入法(BCI)等效替代强场连续波电磁辐射的实验结果进行了分析,验证了BCI 等效替代强场连续波电磁辐射实验方法的准确性。     

Least Squares Boundary Residual Method for the Analysis of Step Discontinuities in Open Chiral Waveguides

We analyse the reflection, transmission and radiation characteristics of a step discontinuity in a grounded chiral slab and we show that the step radiation can be enhanced due to the effect of the chirality. The analysis is performed using a mode matching technique. The fields are expressed in terms of the discrete modes and the continuous spectrum using two subsets of hybrid radiation modes: incident transverse electric (ITE) and incident transverse magnetic (ITM) modes. The scattering matrix of the step is determined by minimizing the boundary residual error in the sense of the least squares. The influence of chirality on the characterization of the step is demonstrated and we show that control of the radiation pattern is achieved, including angle and width of the radiation beam.