Analysis of lossy planar transmission lines by using a vectorfinite element method

The vector finite element method with hybrid edge/nodal triangular elements is extended for the analysis of lossy planar transmission lines. In order to handle lossy conductor transmission lines, the present approach includes the effect of finite conductivity of a lossy area, and the dissipations in metallic conductors and dielectrics are calculated directly by considering a complex permittivity for the lossy region of interest. A propagation constant formulation is used in the FEM, which avoids spurious solutions absolutely and can handle sharp metal edges in inhomogeneous electromagnetic waveguides. Numerical examples are computed for microstrip lines, finlines, and triplate strip lines. The results obtained agree well with the earlier theoretical and experimental results, and thus show the validity of the method. Also, the current distributions on the lossy microstrip lines with finite strip thickness and isotropic substrates are presented     

Reflection analysis for planar surface wave antennas with different tapering profiles

The reflection characteristics of the planar surface wave antennas with different tapering profiles are analyzed by a method which transforms the radiation problem into the transmission problem of the eigen mode in the partially dielectric filled planar waveguide to avoid the difficulty of the field source problem which is met in the traditional analysis. As a result, the analysis procedure is tremendously simplified. The effect of the tapering profile on the reflection property is carefully investigated and extensive numerical results are given to establish useful guidelines for the design of the planar surface wave antennas.     

Millimeter wave twist reflector design aspects

A millimeter-wave twist reflector design procedure is described. An effective dielectric constant for capacitive susceptance correction for a unidirectional planar grating at the interface of free space and dielectric material in the twist reflector environment is introduced. The loss factor of the dielectric material is taken into account for the prediction of twist reflector performance. With the introduction of these corrections experimental results are found to be in close agreement with the theory. Normalized curves for the design of twist reflectors in terms of grating parameters, dielectric substrate relative permittivity, and dielectric material thickness are presented. Experimental results are given     

Design and experimental investigation of a multibeam integrated reflector antenna of the millimeter wave band

A multibeam integrated reflector antenna operating in the millimeter wave band is considered. The antenna consists of a radiating array, a planar mirror, and a multichannel feed. The results of simulation of a radiating array of slots in a metal screen are presented. The array is manufactured on the basis of a medium with forced refraction, including a double-slot array, which can radiate along the normal to the array plane. Operation of the array in the multibeam mode is analyzed. It is shown that application of a medium with forced refraction increases the array aperture efficiency in this mode. The results of the design of a planar two-layer mirror are presented and the mirror’s quality indices are estimated. A multichannel radiator designed as an array of planar H-plane horns is studied. The results of simulation of such a radiator with the help of an approximate technique and numerical solution of an electromagnetic problem are considered. The design of the multibeam antenna and its experimental characteristics are presented.     

Numerical analysis of near-infrared wave propagationcharacteristics in dielectric-coated parallel planar microstructuralwaveguides

In this paper, the properties of electromagnetic (EM) wave propagation in layered planar microstructural waveguides are investigated. Analytical and numerical results are presented on the propagation of a 1-μm EM wave in a parallel planar waveguide. Its walls are made of Au or Si, coated with a thin layer of SiO₂ and separated by a fluid. The propagation characteristics of even and odd TE and TM modes are described as a function of the coating thickness. It is shown that the propagation of TE modes exhibits a sudden shift in power flow distribution from the fluid to the coating when the coating thickness exceeds a critical value. This property may be exploited for micromachined sensor applications. TM modes do not exhibit this behaviour     

Full wave electromagnetic analysis of planar whispering gallerymode DRO

A new type of DRO using whispering gallery modes is presented. The circuit realised in planar technology is characterised using the finite element method. This global electromagnetic analysis enables the output power and the oscillation frequency to be calculated. Theoretical and experimental results are compared for a DRO operating at 15.6 GHz     

Millimeter wave twin slot antennas on layered substrates

We have constructed a planar, monolithic twin slot antenna integrated with a bismuth microbolometer detector for operation near 94 GHz. In this paper, we briefly discuss the theory of operation for planar antennas on a dielectric stack. We then cover the fabrication details, including a short discussion of a photoresist bridge technique used to fabricate the microbolometer detectors. Measured receiver gain beam patterns are then compared with theoretical patterns for a number of cases.     

Diffraction of an electromagnetic wave by a three-dimensional planar lattice

The 3D problem of scattering by a planar lattice of impedance bodies of revolution is solved with the help of the modified discrete source method. A system of integral equations is derived. Numerical results are obtained for the case of perfectly conducting elements of the lattice. The validity of the law of energy conservation is checked.     

Creeping wave propagation constants and modal impedance for a dielectric coated cylinder

The electromagnetic characteristics associated with the creeping waves supported by a dielectric coated cylinder are investigated. The propagation constants and wave impedances of the creeping waves are obtained numerically. Higher order modes which are significant for a thick coating are also investigated. The propagation constants and creeping wave modal impedance are compared with those obtained for a planar dielectric slab backed by a ground plane. It is found that, contrary to the planar configuration, no cutoff frequencies exist for the creeping waves associated with the coated cylinder. In fact, the coated cylinder supports an infinite number of modes. However, depending upon the thickness of the coating, only a few Elliott type creeping wave modes with low attenuation can exist. Furthermore, for each of the Elliott type creeping waves, there is a critical radius for the cylinder below which the Elliott type creeping wave cannot exist. The results are also compared with an impedance boundary cylinder, where the impedance is chosen to be purely imaginary.     

Millimeter wave QWITT diode oscillator

The quantum well injection transit time (QWITT) diode charecteristics, small signal and large signal device models are used. A peak output power density of 35–5 KW/Cm² in the frequency range of 5–8 GHZ hasx been obtained from a planar QWITT Oscillator     

Application of wave theory for two types of planar-diffused opticalwaveguide profiles

Exact dispersion equations and expressions for TE-mode field distribution are obtained for two types of planar diffusion integrated optical waveguides: an Epstein asymmetrical profile and a profile consisting of a parabolic segment and an exponential part. The parabolic profile is considered as a limit case. The exact solutions are used to estimate the applicability and the accuracy of some approximate methods for analysis of planar ion-exchanged waveguides in glass     

Comparison of full wave approaches for determination of microstrip conductor losses for MMIC applications

Losses due to ohmic conductors in planar lines are evaluated by two full wave analyses, the first one using impedance surface concept associated with the modified spectral domain approach (SDA) and the second a more accurate mode matching technique. To state the respective validity domain of the two numerical simulations, results are compared to experimental data.<>     

Full wave approach for the analysis of open planar waveguides withfinite width dielectric layers and ground planes

A unified full wave approach based on an extended method of lines is presented for the analysis of open planar waveguides. It can be used to analyze various open planar waveguides and is suitable especially for dielectric substrates with discontinuities and/or with finite ground planes where a full wave approach is not available yet. The convergence of the method is examined by numerical experiments. As application examples, the dispersion characteristics of open single and coupled microstrip lines with finite dielectric substrates are calculated and compared with the full wave results for structures with infinite width dielectric/conductor and the available quasi-static results for single microstrip line with finite dielectric in the literature. The effect of dielectric width on the characteristics is also discussed     

Multi-layer floorplanning for stacked ICs: Configuration number and fixed-outline constraints

3-D (stacked device layers) ICs can significantly alleviate the interconnect problem coming with the decreasing feature size and is promising for heterogeneous integration. In this paper, we concentrate on the configuration number and fixed-outline constraints in the floorplanning for 3-D ICs. Extended sequence pair, named partitioned sequence pair (in short, P-SP), is used to represent 3-D IC floorplans. We prove that the number of configuration of 3-D IC floorplans represented by P-SP is less than that of planar floorplans represented by sequence pair (SP) and decreases as the device layer number increases. Moreover, we applied the technique of block position enumeration, which have been successfully used in planar fixed-outline floorplanning, to fixed-outline multi-layer floorplanning. The experimental results demonstrate the efficiency and effectiveness of the proposed method.     

Equivalent network representation of boundary conditions involvinggeneralized trial quantities-application to lossy transmission lineswith finite metallization thickness

The derivation of integral equations for solving boundary conditions by mere application of analog Kirchhoff's and Ohm's laws is used. Generalized trial quantities are introduced as virtual adjustable sources in the equivalent network representation of boundary conditions. The lossy conductor domain of a planar transmission line is represented by a particular two-port. Thus, metallic losses can be evaluated for any metallization thickness without restricting the conductor modeling to a simple surface impedance approximation. In this paper, this two-port model is discussed and numerical results relative to a lossy coplanar waveguide (CPW) are presented. These results are in very good agreement with those obtained from the mode-matching technique and with other experimental data available in the literature. The size of matrices involved in the calculation of losses is twice as large as that in the lossless case. Moreover, the authors' formulation can be easily applied to superconducting planar transmission lines     

Finite-difference approach to the solution of time-domain integralequations for layered structures

A numerical algorithm for the analysis of transient electromagnetic fields in planar structures is proposed based on the time-domain magnetic-field integral equation (MFIE), electric-field integral equation (EFIE), and the marching-on-in-time approach. The field vectors are represented in terms of vector potential functions which are calculated either by integration or by the three-dimensional (3-D) wave equation according to the geometry of the structure. Thus, the algorithm combines the advantages of integral equation techniques and finite-difference schemes. While this approach is applicable to any geometries, it is especially suitable for multilayered planar structures and is competitive to the finite-difference time-domain (FDTD) method in the case of open and radiating problems. Theoretical results are verified by the analysis of a pulse propagation in a homogeneous open-end microstrip line     

无线传感网络中低功耗处理器的设计和优化

采用90nm工艺设计实现了应用于无线传感网络中的低功耗处理器. 为了减小功耗，采用了以下两种方法： (1）采用门控时钟技术来降低动态功耗； (2）采用多阈值电压单元库来减小漏电功耗. 通过比较给出了设计优化结果.     

Dependence of linewidth in hexagonal planar ferrites on angle between magnetostatic field and easy plane

Theoretical expressions for the linewidth of a single-crystal hexagonal planar sphere are compared with experimental results with the magnetostatic field taken at an arbitrary direction to the easy plane. It is shown that the overall line-width broadening favours the Bloch-Bloembergen form of damping, in comparison with the Landau-Lifshitz form. As the large anisotropy field is represented in a form identical to a shape-demagnetising field, the results indicate the dependence of the linewidth on the shape of the sample.     

参考光为平面波和球面波时焦距检测对比研究

为了研究参考光波面形状对于测量透镜焦距值的影响,采用数字全息的方法进行了理论分析和实验验证。通过在两种色光下进行实验,分别测量出参考光为平面波和球面波时的焦距值,并与标称值和理论计算值进行了比较。结果表明,当参考光为平面波时,测量到的透镜焦距值与标称值和理论计算值相对误差在5%以上; 而当参考光为球面波时,与两者的相对误差均在2%以下,因此当参考光为球面波时所测量的焦距值精度更高; 通过计算得出这两种参考光所测量的焦距值都在理论焦深范围内,故利用测量焦距值对全息图进行重构时所获得的再现像与用标称值和理论计算值所得到的再现像质量相当。这一结果对测量透镜焦距值和数字全息图重建方面有一定的帮助。     

MSI High-Speed Low-Power GaAs Integrated Circuits Using Schottky Diode FET Logic

A new planar high-density (10/sup -3/ mm/sup 2//gate) GaAs IC technology has been used for fabricating MSI digital circuits containing up to 75 gates/chip. These digital circuits have potential application for gigabit microwave data transmission and processor systems. The circuits consist of Schottky diode FET logic NOR gates, which have provided propagation delays in the 75-200-ps range with dynamic switching energies as low as 27 fJ/gate on ring oscillator structures. Power dissipation levels are compatible with future LSI/VLSI extensions. Operation of D flip-flops (DFF) as binary ripple dividers (/spl divide/2-/spl divide/8) was achieved at 1.9-GHz clock rates, and an 8:1 full-data multiplexer and 1:8 data demultiplexer were demonstrated at 1.1-GHz clock rates. This corresponds to equivalent propagation delays in the 100-175-ps range for these MSI circuits. Finally, a 3x3 parallel multiplier containing 75 gates functioned with a propagation delay of 172 ps/gate and with average gate power dissipations of as low as 0.42 mW/gate.