A Practical Crosstalk Reduction Technique Applied to High-Density Hard Disk Interconnecting Assembly Traces

This research analyzes the field enhancement properties of a subwavelength metallic groove working at 0.4 terahertz (THz), which is potentially applicable as a receiver to enhance THz signals in integrated circuits. We derive the analytic formulation of the field magnification by utilizing the distinctive characteristics of the electromagnetic (EM) field inside and above the groove with the EM field continuity on the upper and lower surfaces of the groove. This method, known as the Bruijn theory, has been applied in acoustics and optics to obtain reflection and absorption coefficients. Then, the dependence of these field enhancement properties on both the groove width and depth is examined by theoretical analysis and numerical simulations consistently. Results show that the field enhancement varies periodically with the groove depth in a period of 0.5λ, featuring the typical Fabry–Perot resonance. The field enhancement is inversely proportional to the groove width due to the cavity effect. Besides, the field intensity can be further enhanced by 10% via appropriately rounding the sharp vertices at the inlet of the groove. Moreover, the incident angle effect on the field enhancing property is explored. An enhancement of >32 dB can be realized at any incident angle with a groove of dimensions 158×225μm2. These results are helpful for understanding the field enhancement mechanism and designing novel THz plasmonic devices, such as an easily manufactured antenna receiver or sensor with simple and compact configuration, as well as offering a feasible solution for the high attenuation problem of THz communications.

Electrical failures in avionics systems may result from connector faults. If fault precursors are not detected in advance, they may lead to hard failures such as open and short circuits that could ultimately result in fire or loss of flight critical systems. Therefore, It is crucial to detect, locate, and characterize fault precursors for timely preventive maintenance and mitigation before hard failures occur. In this paper, a physics‐based connector model consisting of multiple coaxial line sections with different characteristic impedances and lengths is proposed. Method of Moments (MoM) analyses were performed using commercial electromagnetic simulation software, FEKO, for transverse electric and magnetic (TEM) wave propagation through a connector. The physical parameters of the connector were optimized to match the measured S parameters for multiple insertion depths. The proposed models represent the connector for multiple insertion depths by varying only two length parameters at a time while other parameters are fixed. Insertion depth‐dependent resonant frequency shifts observed during measurement are also captured by the model over the full range of fully inserted to barely touching contacts. Hence, the models provide accurate representations of the connector and properly detect precursors to partial insertion faults.

Cylindrical and conical ultra-wideband (UWB) dielectric resonator antennas are presented in this paper. The first part of this work is a parametric study of cylindrical and conical dielectric resonator antennas for Ultra-Large Band applications ranging from 3.1GHz to 10.6GHz. The second part of the work consists of creating a reconfigurable rejection band inside this UWB in order to minimize interference between UWB system and some narrowband systems operating in this frequency range (3.1GHz to 10.6GHz), Such as WiMAX and WLAN. To obtain the rejection band, we etch a rectangular ring slot on the micro-strip-line-fed patch. The control of the band notch is made by displacing the cylindrical or the conical resonator. The results obtained showed that the band notch ranges from 3.2GHz to 4.7GHz for the cylindrical resonator and from 3.2GHz to 5.2GHz for the conical resonator. The proposed structures are simulated with the commercial electromagnetic simulation software “Ansoft HFSS.” The numerical results from different simulations are presented in terms of reflection coefficient and radiation pattern.

An anisotropic impedance surface based on electromagnetic bandgap (EBG) theory is proposed to produce reconfigurable dual-beam radiation through surface-wave (SW) lensing by controlling SW propagation across the surface-to-air interface. The reconfiguration of the lensing effect is triggered by switching between 4.0- and 4.5-GHz frequencies, utilizing the anisotropy of the impedance surface created from two mutually exclusive EBGs along the two orthogonal spaces. The bandgaps are formed by a periodic arrangement of two different split-ring resonators (SRRs) with bandgaps at around 4.0 and 4.5 GHz along the orthogonal y- and x-axes, respectively, producing a strong axially symmetric anisotropy. As a result, a surface-bound wave, i.e., both transverse electric (TE) and transverse magnetic (TM), faces asymmetric propagation reluctance toward these two directions one of which is very high compared to the other at frequencies around the individual bandgaps of the unit cells. The proposed impedance surface is designed and simulated using commercial electromagnetic simulation software and then fabricated and measured to validate the model.

This paper reports the outcomes of an experimental investigation of the shielding effectiveness (SE) for carbon fibre reinforced polymer (CFRP) composites with varying configurations. It focuses on (1) important parameters affecting the SE of CFRP laminates and (2) applicability of the transmission line (TL) theory to predict their shielding properties. Comparison of the SE profiles showed that quasi-isotropic and cross-ply configurations perform equally well in attenuating the unpolarised radiation and only a modest increase of 10 dB is achieved by doubling the number of plies due to increased absorption. The applicability of the TL model for CFRP composites was found to be limited to thin laminates with quasi-isotropic lay-up, for which the accuracy prediction was within 5 dB in the 150 MHz-1 GHz frequency range. The experimental SE values were also compared to the full wave simulation in a commercial electromagnetic simulation software, demonstrating more accurate predictions than any analytical model.

SummaryThis paper presents a wireless local area network (WLAN) spectrum control system that uses active frequency selective shielding walls to selectively reduce or pass WLAN signals in the 5 GHz band indoors. The proposed system utilizes a well‐known active frequency selective structure based on a rectangular loop with PIN diodes and is thus capable of either reducing or passing the WLAN frequency by using the on/off switching of the PIN diode based on the measured electric field strength in indoor. We designed and simulated the proposed active frequency selective shielding wallpaper by using commercial electromagnetic simulation software and confirmed that the proposed structure can reduce the WLAN signal by switching the PIN diode by applying the manufactured prototype on the exterior of an experimental apparatus containing a WLAN receiver antenna that is capable of measuring the received electric field strength. Extension of the results presented herein can be applied to reduce the wireless signal to enhance the spectrum efficiency of an indoor space.

Breakthrough innovations in electrical machines may be limited by parametric overlays and templates provided in commercial electromagnetic simulation software. Disruptive design spaces must therefore be explored using more flexible open-source software solutions. However, a significant scripting effort is necessary to define some new parametric geometries suitable for design optimization based on open source multiphysics solvers. This article illustrates the use of Pyleecan open-source simulation software under Python to more efficiently model, evaluate and optimize disruptive topologies of 2D or 3D electrical machines. The current status of Pyleecan initiative is first presented. Then, the principle and the advantages of the object-oriented approach of electrical machines are detailed. Some examples of complex innovative topologies that can be generated with Pyleecan are then introduced (e.g. complex winding, uneven slot types, multiple rotor and stators), as well as the optimization possibilities. Finally, the development roadmap of Pyleecan project is given.

A virtually centered broad-wall longitudinal slot antenna have been designed and studied using commercial Electromagnetic Simulation Software (CST Microwave Studio). The result obtained for the S21 of such an antenna has been compared with the measured data to find the accuracy of the software. Also the results obtained for the slot have been compared with the more common offset broad-wall longitudinal slot. Different slot characteristics also have been studied by varying different slot parameters. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.

In the paper, we present a straightforward procedure to utilize random rough surfaces with Gaussian probability distribution in commercial full-wave electromagnetic simulation software CST Microwave Studio. Random, two dimensional (2D) matrices with desired size and statistical parameters such as correlation length and root mean square height of the profile are generated in MATLAB®. In order to obtain desired surface parameters, we employ a Gaussian random 2D matrix generator and subsequent filtering with Gaussian 2D filter. A macro in Visual Basic for Application is then developed to convert these matrices into continuous surfaces in CST MWS. Radiation patterns of horizontally and vertically polarized half-wave dipoles are finally evaluated above these surfaces and compared to analytical models.

The modelling of photovoltaic (PV) solar panels requires electrical parameters which are dependent on the manufacturing materials and their physical properties. Manufacturers typically do not disclose detailed physical properties of the PV module, except for some electrical quantities such as open circuit voltage ( V oc ), short‐circuit current ( I sc ), maximum power point voltage ( V m ), maximum power point current ( I m ) and maximum power ( P M ). However, to model the PV panels comprehensively, it is necessary to determine other physical parameters, e.g., series resistance of PV cell ( R s ), shunt resistance of PV cell ( R Sh ) and diode ideality factor ( n ). This paper presents a generalised mathematical model of a PV panel utilising only the quantities provided in manufacturer's datasheet. The proposed modelling technique determines all the PV panel parameters without any explicit repetitive iteration. Although the developed model is general and can be implemented on any software platform, its implementation is demonstrated on a commercial electromagnetic transients simulation software electro magnetic transient including direct current power systems computer aided design. The electrical parameters obtained from the proposed PV panel model are validated for six different commercially available PV panels from their datasheet values and also from measurements provided by National Institute of Standards and Technology for solar irradiation and temperature at nonstandard test conditions.

The small slop approximation (SSA) is an accurate method to calculate the electromagnetic (EM) scattering properties of rough surfaces. However, its computational complexity restricts its application to smaller domains and there is always the need for speedup in very large cases using pure central processing units (CPUs) hardware. With the development of graphics processing units (GPUs), more processors are dedicated to perform independent calculations. In addition, NVIDIA introduced a parallel computing platform, compute unified device architecture (CUDA), which provides researchers an easy way to use processors on GPU. To calculate EM scattering properties on GPU, we reformulate the SSA method with CUDA to take advantage of GPU threads. Because each thread executes synchronously and deals with a corresponding point data of rough surface, the CUDA-based SSA method calculates faster than the pure-CPU equivalent. To overcome memory limitations, the data of large rough surface are stored on hard disk. Moreover, a subsidiary thread is used to deal with the process of data transmission between the memory and the hard disk and reduce transmitting time further. The factors, block size, data transfers, and register, are also discussed in the optimization of the CUDA application. Test cases running on a NVIDIA GTX 460 GPU indicate that two orders of magnitude speedup, including file input and output, is obtained with our new formulation.

Optimizers in commercial electromagnetic (EM) simulation software packages are the main tools for performing antenna design exploration today. However, these general purpose optimizers are facing challenges in optimization efficiency, supported optimization types and usability for antenna experts without deep knowledge on optimization. Aiming to fill the gaps, a new antenna design exploration tool, called Antenna Design Explorer (ADE), is presented in this paper. The key features are: (1) State-of-the-art antenna design exploration methods are selected and embedded, addressing efficient antenna optimization (critical but unable to be solved by existing tools) and multiobjective antenna optimization (not available in most existing tools); (2) Human-computer interaction for the targeted problem is studied, addressing various usability issues for antenna design engineers, such as automatic algorithmic parameter setting and interactive stopping criteria; (3) Compatibility with existing tools is studied and ADE is able to co-work with existing EM simulators and optimizers, combining advantages. A case study verifies the advantages of ADE. Highlights A new antenna design exploration tool, called Antenna Design Explorer (ADE), is presented in this paper. State-of-the-art antenna design exploration methods are selected and embedded, addressing efficient antenna optimization (critical but difficult to be solved by existing tools) and multiobjective antenna optimization (not available in most existing tools). Human-computer interaction for the targeted problem is studied, addressing various usability issues for antenna design engineers. Compatibility with existing tools is studied and ADE is able to co-work with existing EM simulators and optimizers, combining advantages.

An important step of the microwave design process is the adjustment of geometry and material parameters of the structure under consideration to make it meet given performance requirements. Nowadays, it is typically conducted using full-wave electromagnetic (EM) simulations. Because accurate high-fidelity simulations are computationally expensive, automation of this process is quite challenging. In particular, the use of conventional numerical optimization algorithms may be prohibitive as these methods normally require a large number of objective function evaluations (and, consequently, EM simulations) to converge. The adjoint sensitivity technique that recently become available in commercial EM simulation software packages can be utilized to speed up the EM-driven design optimization process either by utilizing the sensitivity information in conventional gradient-based algorithms or by combining it with surrogate-based approaches. Here, several recent methods and algorithms for microwave design optimization using adjoint sensitivity are reviewed. We discuss advantages and disadvantages of these techniques and illustrate them through numerical examples.

External disks (abbr., disks) are common data storage peripherals for hosts. Verifying the disk’s legitimacy is crucial to prevent security issues on a host like privacy leakage and virus propagation before interaction setup. To address this issue, we propose DiskPrint, a novel non-intrusive and replay-resistant disk authentication system that relies on unintentional electromagnetic (EM) emanations from disks’ internal components. The core idea of DiskPrint is that EM signals emitted during data writing can reflect hardware discrepancies among different disks. Based on electromagnetic principles, we establish a theoretical model associating EM signals with built-in electronic components to demonstrate the feasibility of extracting disk fingerprints from such EM emanations. We also propose a series of signal enhancement methods to remove the EM interface and improve the signal-to-noise ratio (SNR) of the EM measurements. To boost the security of DiskPrint, we propose a device-agnostic replay-resistant method by introducing randomness into leaked EM signals. Real-world experiments with 60 disks including hard disk drives (HDDs) and solid state drives (SSDs) from seven brands and 14 models indicate that DiskPrint achieves a 99%+ authentication success rate. Robustness analysis demonstrates DiskPrint’s stability over time. Security study shows its ability to defend against various attacks.

The electromagnetic (EM) sources of the acoustic noise are very concerned in the spindle motor used in the hard disk drives (HDDs). Identifying the effects of these sources is important for high performance hard disk drive products. The electromagnetic analysis results in this paper show that, when the spindle motor is driven by brushless DC (BLDC) mode, the EM torque ripples can be categorized as intrinsic BLDC torque ripple and commutation torque ripple. A set of experiments were designed, tested and analyzed for identifying the effects of these ripples, and the results showed that the commutation torque ripple is the dominant EM source of the acoustic noise.