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A multiple scattering method is proposed for the analysis of substrate-integrated waveguide (SIW) structures in this letter. SIW structures are considered to be parallel plates embedded by the fence of metallic vias (labeled as SIW vias). The addition theorem of cylindrical waves is applied to the calculation of the multiple scattering among SIW vias and coaxial ports. The reflection matrix of SIW vias, which is derived by boundary conditions, can be connected to the radial scattering matrix obtained by the multiple scattering method. This leads to the network parameters in terms of coaxial ports of SIW structures on a plate pair. The accuracy and efficiency of the multiple scattering method are verified by numerical simulations in commercial full-wave solvers.

An intermodulation (IM) generator based on substrate integrated waveguide (SIW) is demonstrated. This generator has maximal 80 dB dynamic range with a size that is smaller than 65 mm × 40 mm × 1.5 mm. A biased Schottky diode is mounted onto the slotted plane of SIW and it consists of a nonlinear dipole to radiate nonlinear signal to the carrier domain and serve as reference signal. A polarized slot helps focus the linear carrier wave onto the diode and construct a bias-controlled IM distortion. The experiment proves that this device can generate the IM3 reference ranges from -112 to -32 dBm at 2 × 43 dBm, while its minimum step can reach lesser than 0.5 dB. This proposed device can serve as tunable IM standards in PIM test and calibrate the commercial PIM tester.

The hybrid boundary-integral equation and finite-element method (BIE/FEM) is efficient for signal/power integrity analysis of multiple vias in a shared antipad (labeled as compact vias) in an arbitrarily shaped power/ground plate pair. According to field distribution between the parallel plate pair, the computation domain of plate pair is decomposed into via domains and plate domain by using a domain decomposition approach. The higher order modes in the proximity of the antipads, which attenuate exponentially along the propagating direction and are confined in the via domains, are calculated by 3-D FEM. On the other hand, in the region outside the via domains, namely, the plate domain, only the zero-order parallel plate modes need to be considered. The network parameters of the plate domain are solved by the boundary-integral method. By enforcing the field continuity conditions along with the segmentation interfaces between via domains and plate domain, the connection of the multi-mode networks of via domains and the impedance matrix of plate domain yields the S-parameter of the entire plate pair, which characterizes the complete noise coupling path from one via structure to another one. The accuracy and efficiency of the hybrid method are verified by comparing with a commercial full-wave solver.

This paper presents a novel passive intermodulation (PIM) prediction method considering random contact behavior using a Monte Carlo method for a coaxial connector. A smart contact model for a contact unit at a microcosmic level is proposed. Using Monte Carlo approximation and micromeasurements, different random distributed contact samples for different contact components inside the coaxial connector are reconstructed. In the experiment, PIM on inner and outer conductor was tested and compared with predication. A good agreement proves the proposed PIM prediction method is efficient. Rather than generating a single PIM prediction value, this method will give a PIM confidence interval for all the potential PIM values considering the contact force statistical behavior. The work will help analyze fluctuated PIM on coaxial connectors and inspire a new method to predict PIM risk.

A novel broadband bandpass frequency-selective surface (FSS) designed for fifth generation (5G) EMI shielding is proposed in this paper. This new design employs the vertical vias into the 2-D periodic arrays, and such a single 2.5-D periodic layer of via-based structure is demonstrated to produce a highly stable angular response up to 60° for both TE and TM polarizations. By cascading two layers of such 2.5-D periodic arrays, the proposed FSS is able to obtain a broad passband as well as the wide out-of-band rejection. Moreover, it has a quite sharp band edge between the passband and the specified stopband. A corresponding equivalent circuit model (ECM) is further developed for better analysis of the operating principle. Finally, a prototype working at the center frequency of around 28 GHz is fabricated and measured. The main novelty of this paper is introducing the 2.5-D concept into designing a wideband FSS, and further reduce the unit size as well as improve the angular stability. Favorable agreement is achieved among the 3-D full-wave simulation, ECM and measurement. All these results demonstrate that the proposed FSS is a good candidate for 5G EMI shielding.

Electromagnetic interference (EMI) is correlated with mode conversion, from differential-mode signals to common-mode currents and further to antenna-mode currents on the outside of cables or enclosures. This paper presents methods to quantify the mode conversion caused by discontinuities in the digital visual interface (DVI) signal link. These discontinuities are mostly present in the DVI connector, the DVI cable, and the connector–cable interface. A systematic approach was developed in this study to isolate and identify the different coupling paths in a high-speed interface (in this case, DVI is shown) and also to identify which discontinuity is most critical to mitigate EMI. The method developed in this study can be used for any high-speed interface in modern communication systems.

A measurement system which uses acoustic vibration to locate passive-intermodulation (PIM) sources in base station antennas is presented. This measurement system uses mechanical vibration to modulate the PIM signal. The modulation of the PIM signal is detected, and its strength or presence/absence is used as guidance for selecting the location of the vibrating transducer. For the method to be successful, the PIM signal must be caused by loose mechanical contacts or loose nonlinear materials. By introducing the acoustic vibration at different locations in the base station antenna and observing if the PIM signal is modulated by the acoustic frequency, the most likely location of the PIM source is identified.

This paper presents an analysis for the PIM behavior on coaxial connector using statistical method. A novel PIM prediction method for coaxial connector considering random contact behavior is proposed and demonstrated. In this work, by using numerical approximation to reconstruct the micro contact force on contact surface based on Monte-Carlo and micro-measurement, the fluctuated PIM level on contact unit can be calculated based on the contact height distribution. In experiment, the tested PIM of coaxial connector was compared with predication. A good agreement between theoretical prediction and test proves the proposed PIM prediction method is efficient. It gives a confidence interval for the potential PIM levels on coaxial connector, which provides a new way to predict the fluctuated PIM behavior.

As telecom equipments evolving toward higher frequency and higher speed, system-level EMI problems become more and more prominent in high frequency. Usually, high speed digital ICs, connectors and PCBs are the most important components in a ICT product, and at the same time, the most complicated and challenging parts for EMI modeling when system level EMI simulation to be performed. In this paper, an equivalent modeling method to solve such problems was investigated and proposed. Through near-field test and modeling, Multi-link superimposition for connector radiation, PCB ACS equivalent modeling, etc., the complexity of modeling such complicated components in big systems is simplified to a large extent and thereby, the accuracy of system-level EMI risk assessment through simulation been greatly improved.

High electromagnetic interference (EMI) radiation is becoming a critical problem as the operating frequency of the electronic devices increases rapidly. In this paper, the mushroom-type electromagnetic band gap (EBG) structure attached on the bottom of the heatsink is proposed to suppress high EMI radiation of packages within a specific frequency range. To confirm the effects of the novel heatsink with mushroom-type EBG structure, full-wave simulation and measurement in the semi-anechoic chamber (SAC) have been carried out to validate and quantify EMI radiation suppression. The proposed novel heatsink with mushroom-type EBG structure can keep EMI radiation at a low level, which offers the remarkable suppression by approximately 10 dB on average in the frequency range from 9.2 GHz to 15.8 GHz in simulation and by approximately 8 dB on average in the frequency range from 9.8 GHz to 15.6 GHz in measurement.

Via resonance effects which are caused by via stub and surrounding shorting vias are investigated in this paper by numerical simulation and theoretical calculation from a via-trace model on multilayer printed circuit boards. It is discovered that via stub can significantly worsen electric performance of the via transition and stub resonance can be eliminated by shortening via stub. For the case of a signal via surrounded by shorting vias, the vertical signal current flowing on the central signal via can excites resonant mode of circular waveguide resonator, which also generate via resonance.

Heat sink is widely amounted above the package substrate for heat distribution. Unfortunately, the resonance between heat sink and package substrate leads to the severe electromagnetic radiation, and results the product not satisfying the relevant EMI (electromagnetic interference) standards. It is a critical to simultaneously obtain the excellent radiation mitigation and desirable thermal management. In this paper, a combination of ring-shaped absorbing material and flat-shaped graphite is proposed. This paper investigates the effectiveness of graphite to mitigate radiation and optimize thermal performance based on a typical wire-bonded (WB) package. The experiment for EMI radiation is conducted in a semi-anechoic chamber. A good agreement between simulation and measurement is obtained.

A hybrid approach, based on the two-dimensional finite-element method (2-D-FEM) and a genetic algorithm (GA) optimization, is used to extract relative permittivity and permeability of ferrites and flexible magnetodielectric composite materials over wide frequency bands. S-parameters of a material under test (MUT) placed into a coaxial fixture are measured by a vector network analyzer and simulated using the 2-D-FEM code. The GA optimization procedure is then used to minimize the discrepancies between the measured and simulated S-parameters by iteratively searching the possible best permittivity and permeability. Multiterm Debye models of wideband complex permittivity and permeability are employed here for a frequency-dispersive MUT. This greatly reduces the number of unknowns in the GA optimization. The proposed method is tested with PTFE and a virtual magnetic material.

A hybrid 3-D and equivalent 2-D finite-element method (FEM) is proposed for signal/power integrity analysis of multiple vias in a shared anti-pad in an arbitrarily shaped parallel-plate pair. The entire domain of the plate pair is decomposed into via-domains and plate domains by virtual interfaces. Complicated fields in via-domains, due to mode conversions from transverse electromagnetic modes in anti-pads or via-holes to parallel-plate modes, are described by a 3-D FEM while in plate domains, only the zeroth-order parallel-plate modes are assumed to exist a little far away from anti-pads. Triangular prism elements are utilized in both via-domains and plate domains. It is proven that the 3-D triangular prism element can be reduced to an equivalent 2-D triangle element by a novel edge numbering process and the boundary conditions along the interfaces of via-domains and plate domains can be automatically satisfied. The accuracy of the hybrid method has been validated by comparison with other numerical methods, and its flexibility, as well as efficiency, are also demonstrated.

Far-field prediction for electromagnetic interference (EMI) testing is achieved using only magnetic near-field on a Huygens's surface. The electrical field on the Huygens's surface is calculated from the magnetic near-field using the finite element method (FEM). Two examples are used to verify the proposed method. The first example uses the field radiated by an infinitesimal electric dipole. The calculated results are compared with the analytical solution. In the second example, the calculated results are compared with full-wave simulation results for the radiation of a print circuit board (PCB). The validity of this method when the near-field is high-impedance field is verified as well. Sensitivity of the far field to noise in both magnitude and phase in the near-field data is also investigated. The results indicate that the proposed method is very robust to the random variation of both. The effect of using only four sides of the Huygens's box is investigated as well, revealing that, in some instances, the incomplete Huygens's box can be used to predict the far field well. The proposed method is validated using near-field measurement data taken from a sleeve dipole antenna. The error for the maximum far-field value is in only 1.3 dB.

High-sensitive field probes are highly desirable for radio-frequency (RF) interference studies, where ultralow noise levels are of interest. By incorporating an LC resonant circuit in a differential-loop probe, together with a Marchand balun, a magnetic-field probe with enhanced sensitivity is developed. Its equivalent circuit model and design methodology are established. The design is validated by measurements. The measured relative sensitivity in terms of |S21| of the proposed probe increases by approximately 8.63 dB at the resonant frequency of 1.575 GHz compared to that of a conventional design. The advantage of the proposed probe is validated through its application in the measurement of a microstrip trace and a real-world cell phone design.

In mixed radio-frequency (RF) and digital designs, noise from high-speed digital circuits can interfere with RF receivers, resulting in RF interference issues such as receiver desensitization. In this paper, an effective methodology is proposed to estimate the RF interference received by an antenna due to near-field coupling, which is one of the common noise-coupling mechanisms, using decomposition method based on reciprocity. In other words, the noise-coupling problem is divided into two steps. In the first step, the coupling from the noise source to a Huygens surface that encloses the antenna is studied, with the actual antenna structure removed, and the induced tangential electromagnetic fields due to the noise source on this surface are obtained. In the second step, the antenna itself with the same Huygens surface is studied. The antenna is treated as a transmitting one and the induced tangential electromagnetic fields on the surface are obtained. Then, the reciprocity theory is used and the noise power coupled to the antenna port in the original problem is estimated based on the results obtained in the two steps. The proposed methodology is validated through comparisons with full-wave simulations. It fits well with engineering practice, and is particularly suitable for prelayout wireless system design and planning.

This paper studies the accuracy of the physics-based via model, specifically when applied to dense via arrays. The physics-based model uses Green's functions for cylindrical waves in radial waveguides to model the via return current paths and the coupling between vias. The effects of approximations made in this model are studied with regard to four types of modes based on an eigenmode expansion for the radial waveguide. It is found that for the mode conversion in the vicinity of the via, an accurate consideration of nonpropagating modes becomes critical with an increasing cavity height. For the interaction between vias in dense arrays, anisotropic modes have an impact for small pitches, whereas the coupling by nonpropagating modes is small for practical printed circuit board dimensions. For a data rate of 20 Gb/s, conclusions with regard to the applicability of the physics-based via model to a multilayer structure are drawn. For 80-mil pitch, a good agreement to full-wave results can be observed. Measurements have been carried out to validate this finding. For 40-mil pitch, the accuracy of the physics-based via model is not sufficient for data rates of 20 Gb/s or higher.

Numerical addition theorems of both axially anisotropic and axially isotropic parallel-plate modes are derived using a method based on boundary integral equations. This leads to a generalized multiple scattering (GMS) method for signal/power integrity analysis of dense vias in an arbitrarily shaped plate pair, which overcomes the limitation of the conventional multiple scattering method depending on the analytical addition theorems in an infinitely large or a finite circular plate pair. Both the numerical addition theorems and the GMS method have been validated by comparing results with either analytical expressions for special cases or full-wave simulations for more general cases. Several examples are provided to demonstrate the advantages of the generalized method over previous via models by taking into account the axially anisotropic modes due to the asymmetry caused by dense vias and/or arbitrarily shaped power/ground plate edges on via performance.

An improved multiple scattering method is developed for an irregular plate pair where via pad/antipad radius is electrically small and the spacing between any two vias is relatively large so that the axially anisotropic parallel plate modes can be neglected. The plate-pair impedance matrix, widely used as an important parameter in power integrity analysis and also a critical part for via coupling in the intrinsic and the physics-based via models, is found to be related to the addition theorems of the zero-order axially isotropic propagating modes. As the impedance matrix of an irregular plate pair can be calculated by many analytical and numerical methods, the relationship between the plate-pair impedance matrix and the addition theorems of the zero-order axially isotropic propagating modes enables the handling of both the mutual coupling among vias and the reflection from plate-pair edges. Thus, the conventional multiple scattering method, restricted to either an infinitely large or a finite circular plate pair, can be extended to irregular plates for the via structures described earlier. The assumptions of the method are discussed and several numerical examples are provided to validate the proposed improved method.

In this paper, an efficient cascaded microwave network approach is presented for power and signal integrity analysis of multilayer printed-circuit boards (PCBs) and advanced electronic packages with multiple signal traces, multiple power-ground plates, multiple vias, and external loads such as decoupling capacitors. Each parallel-plate pair, which consists of two consecutive conductor plates functioning as either power or ground in the PCBs or packages, is modeled as one individual microwave network. Equivalent circuits are used in the microwave network to model the vias, and a parallel-plate impedance matrix is formulated to account for the wave interactions between the vias and the boundary of the PCB or package. If signal traces are present in a plate pair, a modal decomposition and recombination approach is employed to model two associated modes: the transmission line mode for the signal traces, and the parallel-plate mode for the power-ground plate pair. The microwave networks for each plate pair are finally cascaded together by enforcing the continuity of the voltages and currents at the via clearance holes in the conductor plate shared by two consecutive plate pairs. Numerical validation reveals that the cascaded microwave network approach produces accurate simulation results with much less central processing unit time and memory requirements than 3-D full-wave approaches.

Rigorous analysis of via-plate-pair interactions requires the impedance of a plate pair to be defined in terms of radial transmission lines on perfect magnetic conductor (PMC) ports. The plate domain is not a solid plate pair but one with multiple PMC holes where conventional impedance definitions are not suitable. A new impedance definition is proposed where port voltages and currents are expressed in terms of the inward and outward zero-order modes of a radial transmission line. Radial scattering parameters among multiple radial ports are then introduced and the transforms between the radial scattering and impedance matrices are given. An analytical formula for the radial scattering matrix in a circular plate pair is derived using the addition theorems of cylindrical waves. Furthermore, a boundary integral-equation method is developed to calculate the radial scattering matrix for any irregular plate pair. The method is validated by analytical and numerical simulations as well as measurements.

A cascaded S-parameter method is proposed in this paper for signal/power integrity analysis of multiple vias in a multilayer printed circuit board (PCB). The proposed method enables efficient and accurate construction and simulation of physics-based via model for complex multilayer PCB structures involving vias. The physics-based via model describes the parasitic effects near each via region as well as mutual coupling among different vias. In this model, each via portion between two parallel plates is regarded as a three-port network with two coaxial ports and one radial port between the two plates. A procedure is first developed to obtain the S-parameters of a single plate pair, which combine the three-port via networks with the impedance matrix of the parallel-plate pair. Once the S-parameters of each plate pair are obtained, an assembling technique for cascading microwave networks is further developed. The method proposed in this paper has been validated by both simulations with a commercial circuit simulator and measurements.

A methodology to efficiently design products based on magneto-dielectric (ferrite) materials with desirable frequency responses that satisfy electromagnetic compatibility and signal integrity requirements over RF and microwave bands is presented here. This methodology is based on an analytical model of a composite magneto-dielectric material with both frequency-dispersive permittivity and permeability. A procedure for extracting complex permittivity and permeability of materials from experimental data is based on transmission line measurements. The genetic algorithm is applied for approximating both permittivity and permeability of materials by series of Debye frequency dependencies, so that they are represented as “double-Debye materials” (DDM). The DDM is incorporated in the finite-difference time-domain numerical codes by the auxiliary differential equation approach.

An irregular plate pair with multiple vias is analyzed by the segmentation method that divides the plate pair into a plate domain and via domains. In the via domains, all the parallel-plate modes are considered, while in the plate domain, only the propagating modes are included to account for the coupling among vias and the reflection from plate edges. Boundary conditions at both vias and plate edges are enforced and all parasitic components of via circuit are expressed analytically in terms of parallel-plate modes. The work presented in this paper indicates that a previous physics-based via circuit model from intuition is a low-frequency approximation. Analytical and numerical simulations, as well as measurements, have been used to validate the intrinsic via circuit model.

An efficient microwave network method is proposed for signal and power integrity analysis of a multilayer printed circuit board with multiple vias and decoupling capacitors. The multilayer parallel plate structure is described as a cascaded microwave network. The admittance matrix of a single plate pair with ports defined in via holes both on top and bottom plates is obtained through the intrinsic via circuit model and impedance matrix between two plates. A recursive algorithm is provided to obtain the combined admittance matrix of two layers of plate pair coupled through via holes on a common plate. Decoupling capacitors are naturally treated as impedance loads to the cascaded admittance network. Numerical simulations and measurements have been used to validate the method and good agreements have been observed. While the method is as accurate as full-wave numerical solvers, it achieves much higher efficiencies both in CPU time and memory requirements.

The ever-increasing demands of digital computing and wireless communication have been driving the semiconductor technology to change with each passing day. Modern electronic systems integrate more complex components and devices, which results in a very complex electromagnetic (EM) field environment. EM compatibility has become one of the major issues in ICs redesign, mainly due to the lack of efficient and accurate simulation tools and expertise on noise reduction and immunity improvement. This paper reviews the state of the arts of IC, electronic package, and printed circuit board simulation and modeling technologies. It summarizes the modeling technologies for both available structures [multilayered power-ground planes and macromodeling of interconnect (INC)] and novel structures (nano-INCs and 3-D ICs based on through-silicon via technology). It also illustrates the trends of simulation and modeling technologies in EM compatibility, signal integrity, and power integrity.

A hybrid scattering matrix method (SMM) and a modal decomposition technique for analysis of signal traces in the power distribution network of an electronic package are presented in this paper. Applying the modal decomposition of the waves propagating inside the power-ground (P-G) planes and the signal traces, the electromagnetic fields can be decomposed into the parallel-plate mode and the transmission-line mode. The former is analyzed by using the SMM for the finite P-G planes with multiple vias. The multiconductor transmission-line theory is applied to model the micro-stripline and stripline in the package. Numerical simulations are illustrated for coupling analysis of P-G vias to the signal traces in the package and examined through experimental and numerical validations.

Analytical models for vias and traces are presented for simulation of multilayer interconnects at the package and printed circuit board levels. Vias are modeled using an analytical formulation for the parallel-plate impedance and capacitive elements, whereas the trace-via transitions are described by modal decomposition. It is shown that the models can be applied to efficiently simulate a wide range of structures. Different scenarios are analyzed including thru-hole and buried vias, power vias, and coupled traces routed into different layers. By virtue of the modal decomposition, the proposed method is general enough to handle structures with mixed reference planes. For the first time, these models have been validated against full-wave methods and measurements up to 40 GHz. An improvement on the computation speed of at least two orders of magnitude has been observed with respect to full-wave simulations.

An analytical model for a magneto-dielectric composite material is presented based on the Maxwell Garnett rule for a dielectric mixture, and on Bruggeman's effective medium theory for permeability of a ferrite powder embedded in a dielectric. In order to simultaneously treat frequency-dispersive permittivity and permeability of a composite in a full-wave FDTD code, a new algorithm based on discretized auxiliary differential equations has been implemented. In this paper, numerical examples of modeling structures containing different magneto-dielectric mixtures are presented.

This paper presents a semi-analytical approach for electrical performance modeling of complex electronic packages with multiple power/ground planes and large number of vias. The method is based on the modal expansion technique and the method of moments. For the inner package domain with multiple power/ground planes and many vias, the modal expansion method is employed to compute the electromagnetic fields from which the multiport network parameters, e.g., the admittance matrix can be easily obtained. For the top/bottom domain of signal layers, the moment method is used to extract the equivalent resistance, inductance, capacitance, and conductance (RLCG) parameters. The equivalent circuit for the entire package is then generated by combining the results for both package domains. The equivalent circuit can be used in a SPICE-like simulator to study the signal and power integrity of an electronic package. Numerical examples demonstrate that the new approach is able to provide fast yet accurate signal and power integrity analysis of multilayered electronic packages.

This paper presents the measurement validation of reciprocity theorem method for near-field coupling estimation. The overall problem is decomposed into two parts, the first part is called forward problem, and the second part is called the reverse problem. For forward problem, the noise source IC is modelled by physics-based dipole moment model with data obtained from a near-field scanning plane, then the tangential E and H fields on a Huygens's box enclosing the victim antenna are calculated by analytical expression. In reverse problem, the victim RF antenna is modelled in full-wave simulation tool and the tangential E and H field are obtained by simulation. With tangential E and H field obtained in forward problem and reverse problem, the coupled noise power is then estimated by reciprocity theorem. The estimated noise coupling power is compared with measured power at the victim antenna port with IC excited. The difference is within 5dB which is acceptable for engineering practice.

This paper is focused on the construction of a conducted-emission model for a switched-mode power supply (SMPS). First, the total voltage source is extracted by measurement. Second, the coupling path between the aggressor and the victim is characterized by both simulation and measurement. Finally, the coupled noise to the victim with respect to the extracted total voltage source can be obtained by both simulation and calculation. Both results match well with the measurement result, which validates the robustness of the constructed model.

This study is to estimate the near-field coupling in mixed digital/RF circuit design for modern high speed electronic systems. The noise source IC is first modelled by physics-based dipole moment model with data obtained from a near-field scanning plane. The victim RF antenna is modelled in full-wave simulation tool and the noise IC is further modelled as Huygens's equivalent source. The tangential fields on the Huygens's box can be calculated by dipole moment model with negligible multiple scattering effect assumption. The noise coupling then can be obtained by surface integration of Poynting vector at the RF antenna receiving port. A full-wave simulation model is first studied to demonstrate the method and a noisy clock buffer IC with victim patch antenna is measured for further validation.

The radiation mechanisms from two-wire transmission lines in the gigahertz range were analysed through method of moment (MOM) and the developed analytical formula. Total radiation power (TRP) was used to evaluate the radiation from a straight two-wire transmission line and a two-wire transmission line with right-angle bends. The contribution of the wire segments connecting the source and load to the two-wire transmission line and the contribution of the right-angle bends to the TRP were analysed with travelling wave currents on the two wires. The increase of TRP from the bent wire is due to the change of the current locations, not caused by the reflections at the bends. With standing-wave currents on the wires, the radiation increases dramatically at half-wavelength resonances when there is significant increase of current magnitude at these resonances.

A differential via structure with four varying factors are defined in this paper. The Monte Carlo (MC), stochastic collocation (SC) and design of experiments (DoE) methods are employed to quantify the drilling uncertainties in the abovementioned via structure. A comparison of the results shows that the SC method is more robust and can more efficiently and accurately estimate the mean and the standard deviation of the responses, compared to the DoE method.

Recent development of Electron Backscattering Diffraction (EBSD) technique has advanced to allow users to perform Transmission Kikuchi diffraction (TKD), and also known as transmission-EBSD (t-EBSD) with the existing conventional EBSD detector, and field emission scanning electron microscope (FESEM). More importantly, this technique has been known for the significant improvement in spatial resolution. In this paper, this technique has been employed to characterize a high topography surface Aluminum sample containing submicron or smaller grain sizes, which is a limitation to the conventional EBSD method because a conventional EBSD method requires relative smooth and flat surfaces. The objective of this paper is to illustrate the successful employment of t-EBSD technique, to obtain the mean grain size of Aluminum prepared by Physical Vapour Deposition (PVD), as well as to determine percentage of grains orientation grown in parallel to the growth direction to the silicon substrate or simply the normal direction (ND) as specify in during the ESBD analysis run. This paper will account on how the sample was prepared by means of FIB to achieve and electron transparent TEM foil. Results has shown that 81% of the desired orientation parallel to the ND direction (i.e. //ND) and a mean grain size of 0.317um were determined, with more than 50% of the area mapped contain grains equivalent diameter less than submicron size. Therefore, t-EBSD is a relatively effective application towards this study because this does not compromise on the spatial resolution less than submicron scales.

The Multilevel Fast Multipole Method (FMM) is a well-established method and can be applied to solve electromagnetic (EM) scattering problems. Compared with other traditional methods, it requires less computational time and memory. However, constrained by a single processor's speed and memory limitations, the problem size that can be solved by serial implementation is still relatively small. For a million-unknown target, the computational time on a single processor is intolerable, and memory could be easily exhausted. Parallel-computing technology, which can utilize multiprocessors, provides an efficient way to solve electrically large-scale EM problems. This paper will focus on discussing the parallel methodologies applied to a multilevel FMM code, as well as demonstrating the computational efficiency of the parallel approach.

This paper presents an efficient simulation algorithm-Scattering matrix method for investigation of the coated finite two-dimensional electromagnetic bandgap (EBG) structures. The method is derived to be capable to simulate the band properties of the coated cylinder photonic crystal with wave discontinuities. Numbers of photonic crystals with waveguide discontinuities are examined. The transmission characteristics of the EBG embedded with metal, dielectric, and various coated cylinders are analyzed. The results show that the tuned bandgap properties are able to provide an additional possibility to develop a novel device.

The average power-handling capability (APHC) of the signal line in finite-ground coplanar waveguides (FGCPWs) on polyimide and GaAs substrates is evaluated in this paper. In our approach, the ohmic loss of metal lines is characterized in different ways, and the effects of an irregular edge shape are also considered. The rise in temperature of the signal line is determined by single- and double-layer thermal models, with the temperature-dependent properties of the thermal conductivity of GaAs material treated appropriately. Parametric studies are carried out to investigate the overall effects of signal-line width, thickness, conductivity, edge-shape angle, and polyimide thickness on APHC. Some possible ways to enhance the APHC of these FGCPWs are also proposed. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.

Parallel fast multipole method is developed for radar cross section (RCS) computation of large targets on multiple processor systems. The sparse matrices in fast multipole method (FMM) are calculated and stored in distributed processors and message passing interface (MPI) is used to perform the matrix-vector product in parallel iterative solvor. The accuracy of the code is verified by comparison with the results of benchmark targets. Either the computational complexity or speed-up ratio of parallel FMM and MoM are compared.

This paper presents a novel approach to alternate the electromagnetic properties of the electromagnetic band gap (EBG), where a ferrite defect is introduced, and in addition, a DC magnetic field is applied to alternate the EBG's electromagnetic property. Numerous devices are examined, including a coupler and a Y-branch filter. The numerical experiments demonstrate that the devices electromagnetic characteristics can be easily adjusted by varying the DC magnetic-field intensity. In this paper, the examinations are performed using the scattering-matrix method. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 395–400, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20481

An accurate model is presented for micromachined on-chip spiral inductors, in which the high-frequency current crowding effects in metal traces are considered by simplified partial element equivalent circuits, and the substrate parasitics are extracted by the parametric modeling method. The model has been confirmed by both measurements and the results from the 3-dimensional finite element method. This equivalent circuit model enables the prediction and optimization of high-Q micromachined spiral inductors in gigahertz frequencies. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 229–238, 2003.