Multilevel Surface Decomposition Algorithm for Rapid Evaluation of Transient Near-Field to Far-Field Transforms

A fast multilevel algorithm with reduced memory requirements for the evaluation of transient near-field to far-field transforms is presented. The computational scheme is based on a hierarchical decomposition of an arbitrary shaped enclosing surface over which the near-fields of an antenna or a scatterer are given. For surface subdomains at the highest decomposition level, the angular-temporal far-field patterns are calculated directly from the known near fields over a sparse angular grid of directions and a short temporal duration. The multilevel computation comprises angular and temporal interpolations thus increasing angular resolution and temporal duration of radiation patterns while aggregating the subdomain contributions between successive decomposition levels. These steps are repeated until obtaining the transient far-field response of the whole enclosing surface. The computational complexity of the proposed algorithm is substantially lower than that of the direct evaluation. Reduction in memory requirements is obtained by formulating the algorithm as a marching-on-in-time windowed scheme. This approach allows for embedding of the accelerated transforms within existing near-field modeling tools.      

Analysis of High-Performance Flip-Flops for Submicron Mixed-Signal Applications

This paper presents a detailed analysis of high-performance edge-triggered memory elements for deep submicron mixed-signal applications. The variations of the main parameters (power, delay, peak of supply current) with supply voltage, as well as timing restrictions have been studied. Especial emphasis has been given to switching-noise generation, an aspect of important concern in mixed-signal applications. We have analyzed the sources of switching noise, noticing that, the less noisy flip-flops are those based on differential structures.     

An Electromagnetic Near-Field Sensor for Simultaneous Electric and Magnetic-Field Measurements

This paper describes the theory of a single sensor to perform simultaneous electric and magnetic near-field measurements. The theory indicates that it is possible to measure the magnetic-loop and electricdipole currents using a loop antenna terminated with identical loads at two diametrically opposite points. The theory also indicates that it is possible to choose an ideal load impedance for achieving equal electric and magnetic-field responses of the loop. Preliminary experiments have been performed using a plane-wave field to verify these results.     

A Double-Surface Electromagnetic Bandgap Structure With One Surface Embedded in Power Plane for Ultra-Wideband SSN Suppression

In this letter, a double-surface electromagnetic bandgap (EBG) structure with one EBG surface embedded in power plane is proposed for ultra-wideband simultaneous switching noise (SSN) suppression in printed circuit boards. The SSN suppression bandwidth is broadened to wider than 30 GHz with a low start frequency by combining traditional EBG structure and the coplanar EBG structure which is embedded in the power plane. Because the coplanar EBG surface is embedded in the power plane, no additional metal layer is introduced by the double-surface EBG structure. Simulations and measurements are performed to verify the broadband SSN suppression, high performance is observed.     

HC-PCF的传输特性及其应用

简要介绍了光子晶体的原理,由此引出光子带隙型光子晶体光纤的概念、结构、导光机理及其制备,着重分析空气导光型光子晶体光纤的传输特性,并用时域有限差分(FDTD)法仿真了三角形结构空气导光型光子晶体的色散特性,最后展望其应用前景.     

Study on the Microwave Transmission Characteristics of a Three-Dimensional Electromagnetic Bandgap Structure with Coupled Defects

The influence of a vertical coupled defect on the localized properties of a diamond electromagnetic bandgap (EBG) structure has been studied in the present research. The diamond EBG structure with a cavity defect was fabricated by stereolithography and gel-casting processes with alumina slurry. The resonant peaks of two kinds of defects were compared by measuring their microwave transmission characteristics using a network analyzer. A higher quality factor (Q) was obtained for the diamond EBG structure with a vertical coupled defect, and the transmission efficiency of resonant peak was improved by 29.6% in comparison with a single defect. Experimental results agreed with the simulation results. These microwave transmission characteristics of the three-dimensional (3D) EBG structures indicate that they can be applied in microwave devices to improve transmission efficiency.     

Statistical Analysis and Optimization of a Bandgap Reference for VLSI Applications

Voltage and current references are widely needed for all kinds of integrated circuits, as most applications require temperature-independent references with a high reproducibility in mass production. For this purpose normally bandgap references are used. Though it is a common task to set up an application specific bandgap circuit, handling of the statistical design aspects is often not a standardized step in the design flow. This article describes some of the steps that were taken during the design of a bandgap reference for a given VLSI application. All statistical simulations were carried out with the simulation tool GAME (General Analysis of Mismatch Effects) which is used at Infineon/Düsseldorf since 1999.     

Review of Near-Field Terahertz Measurement Methods and Their Applications

In the last decades, many research teams working at Terahertz frequencies focused their efforts on surpassing the diffraction limit. Numerous techniques have been investigated, combining methods existing at optic wavelength with THz system such as Time Domain Spectroscopy. The actual development led on one side to a resolution as high as ??/3000 and one the other side to a video-rate recording. The purpose of this paper is to give an overview of the history of the field, to describe the different approaches, to give examples of existing applications and to draw the perspective for this research area.     

纳米光存储薄膜结构的光学性质

近场超分辨纳米薄膜结构可以突破衍射极限实现纳米尺寸信息存储,是下一代海量存储技术的重要方案之一,也是纳米光子学研究中的热点.纳米膜层结构基于激光作用下的非线性局域光学效应实现超分辨.分析了超分辨近场薄膜结构突破衍射极限的光学原理,对超分辨纳米薄膜结构的表面等离子体激发特性、非线性光学特性、近场光学特性和超透镜效应等重要光学性质的最新研究进展做了系统介绍.     

宽禁带半导体技术最新进展

介绍DARPA宽禁带半导体技术计划第二阶段计划目标及其演示进展情况.     

A Novel Compact Spiral Electromagnetic Band-Gap (EBG) Structure

A novel compact electromagnetic band-gap (EBG) structure in a spiral shape is presented and investigated. This structure significantly enlarges the capacitance between neighboring elements. The simulations and experimental results have proved that the size of the spiral structure is only 30.9% of the conventional EBG structure. Two applications have been shown, including patch antenna with the spiral EBG structure and a double-element microstrip antenna array with low mutual coupling. The measured results show that a gain improvement over 3 dB and a significant reduction of cross polarization in H-plane are obtained. A 6 dB reduction of mutual coupling is achieved in a double-element EBG microstrip antenna array.     

A S-Bridged Inductive Electromagnetic Bandgap Power Plane for Suppression of Ground Bounce Noise

In this letter, a novel power plane using an inductive S-bridged electromagnetic bandgap (EBG) is proposed for ultra wideband suppression of the ground bounce noise. The S-shaped bridge detouring unit cells effectively increase the power plane inductance. -30 dB stopband is realized from 220 MHz to 7 GHz. The stopband lower limit (220 MHz) of the proposed EBG has been greatly reduced from that (550 MHz) of L-bridged EBG. It is expected that the number of local decoupling capacitors for the power plane integrity is reduced using the proposed S-bridged EBG without the self resonance effect.     

一维平板光子晶体中电磁波的模式和带隙

利用特征矩阵法研究了一维平板光子晶体中电磁波的模式及其带隙结构。推导出一维平板光子晶体中电磁波各个模式满足的条件,计算出TE波和TM波各模式的禁带随模式量子数、平板厚度以及入射角的变化规律。得出了一些不同于一维非受限光子晶体禁带的新结构。     

Complex-Point Dipole Formulation of Probe-Corrected Cylindrical and Spherical Near-Field Scanning of Electromagnetic Fields

A probe-corrected electromagnetic theory based on complex-point dipoles is presented for computing the field of an arbitrary source of finite extent (for example a test antenna) from measurements of its near field on a cylindrical or spherical scanning surface. By representing the probe with complex-point dipoles, probe correction is achieved by simple factors that involve Hankel functions evaluated at complex points. Only four complex-point dipoles are needed to represent a typical precision probe used in near-field measurements. The theory uses neither translation and rotation theorems nor differential operators. One disadvantage of the theory is that it employs nonlinear optimization to determine the parameters of the probe model. The complex-point dipole representation of the probe makes realistic simulations of near-field scanning systems straightforward. The cylindrical theory is validated through a numerical example. The spherical theory is validated by experimental data.     

A Numerical Methodology for the Prediction of the Near-Field Parasitic Electromagnetic Emissions of Solar Panels

This paper presents a methodology that is developed to assess the parasitic electromagnetic (EM) emissions of a satellite solar panel from a quasi-static to several tens of megahertz bandwidth. In the method, the solar panel is first modeled as an equivalent electric circuit, which allows the computation of the current distribution in all the elements using Spice-like software. The model is then converted into a network of electric dipoles, which permits to calculate the total EM emissions of the solar panel at a given point by the vectorial summation of the EM emissions due to each electric dipole. Thus, only the dipolar moment and the position and the orientation of each electric dipole are required. Encouraging experimental validations performed on a prototype solar panel are presented to illustrate the efficiency and the accuracy of the method. The method described in this paper is considered as a first step required in order to prepare wider applications on real satellites in the near future.      

Subthreshold Performance of Dual-Material Gate CMOS Devices and Circuits for Ultralow Power Analog/Mixed-Signal Applications

Analog circuits based on the subthreshold operation of CMOS devices are very attractive for ultralow power, high gain, and moderate frequency applications. In this paper, the analog performance of 100 nm dual-material gate (DMG) CMOS devices in the subthreshold regime of operation is reported for the first time. The analog performance parameters, namely drain-current (I_d), transconductance (g_m), transconductance generation factor (g_m/I_d), early voltage (V_A), output resistance (R_o) and intrinsic gain for the DMG n-MOS devices, and and for the DMG p-MOS devices are systematically investigated with the help of extensive device simulations. The effects of different capacitances on the unity-gain frequency are also studied. The DMG CMOS devices are found to have significantly better performance as compared to their single-material gate (SMG) counterpart. More than 70% improvement in the voltage gain is observed for the CMOS amplifiers when dual-material gates, instead of single-material gates, are used in both the n- and p-channel devices.     

Practical Harmonic Cancellation Techniques for the On-Chip Implementation of Sinusoidal Signal Generators for Mixed-Signal BIST Applications

Harmonic cancellation strategies have been recently presented as a promising solution for the efficient on-chip implementation of accurate sinusoidal signal generators. Classical harmonic cancellation techniques consist in combining a set of time-shifted and scaled versions of a periodical signal in such a way that some of the harmonic components of the resulting signal are cancelled. This signal manipulation strategy can be easily implemented using digital resources to provide a set of phase-shifted digital square-wave signals and a summing network for scaling and combining the phase-shifted square-waves. A critical aspect in the practical implementation of the harmonic cancellation technique is the stringent accuracy required for the scaling weight ratios between the different phase-shifted signals. Small variations between these weights due to mismatch and process variations will reduce the effectiveness of the technique and increase the magnitude of undesired harmonic components. In this work, different harmonic cancellation strategies are presented and analyzed with the goal of simplifying the practical on-chip implementation of the scaling weights. Statistical behavioral simulations are provided in order to demonstrate the feasibility of the proposed approach.     

Suppression of EMI and Electromagnetic Noise in Packages Using Embedded Capacitance and Miniaturized Electromagnetic Bandgap Structures With High-k Dielectrics

A novel miniaturized simple planar electromagnetic bandgap (EBG) structure is proposed. The new structure mitigates different types of electromagnetic noise in packages. The design of the new EBG structure proposed here relies on the use of high-k dielectric material (epsiv_r >100), and consists of Meander lines and patches. The Meander lines serve to provide current continuity bridges between the capacitive patches. High-k dielectric material increases the capacitance of the patches substantially in comparison to commonly used material with much lower dielectric constant. Simulation results are provided to show that using the proposed EBG, it is possible to obtain a very wide stop band (~ 10 GHz) which covers the operating frequency of current processors and a wide range of the resonant frequencies of a typical package. The wideband is obtained using a unit cell of less than 2 mm.