Design and Analysis of Ultra-Miniaturized Meandering Photonic Crystals Delay Lines

In this paper, we study the characteristics of a novel miniaturized optical delay line, which delays light in a meandering photonic crystal waveguide, and describe the design steps. We show how lattice parameters and refractive index difference of the photonic crystal affect the bandgap width and suggest a criterion to select these parameters. Next, we focus on the parallel waveguide channels in photonic crystal, and analyze the impact of the channel length and the interchannel spacing on crosstalk. We suggest a method for mitering the sharp corners in meandering lines which reduces the undesired reflections by 8 dB. Considering all these guidelines, we examine the propagation of light in the proposed delay line through calculating time-delay and insertion loss. To achieve longer delays in a small device area, we concentrate on coupled cavities in photonic crystals and propose an approximate method for calculating the group velocity of light in the coupled defects. We show how by replacing waveguide channels of a meandering delay line with coupled defects we achieve time-delays more than 9 ps within a device size around 27 m, which corresponds to a miniaturization factor of 100.     

Design of a matching network for an HF antenna using the realfrequency method

The real frequency method (RFM) is used to design a matching network for an electrically short loaded dipole. The RFM is demonstrated to be superior to other analytical and numerical techniques in the sense that it yields the maximum flat transducer power gain possible, and that it does not require any analytical modeling of the load impedance to be matched. For this reason, the RFM is found to be well suited for matching distributed systems such as antennas     

The complementary derivatives method: a second-order accurate interpolation scheme for non-uniform grid in FDTD simulation

Non-uniform grid in finite-difference time-domain methods, which is typically used to resolve fine structures, can reduce the computational domain and therefore lead to a reduction of the computational cost. However, for high-accuracy problems, such as partially-filled parallel plate waveguide and resonators, using different grid size increases the truncation error at the boundary of domains having different grid size. To address this problem, in this work, we introduce the complementary derivatives method (CDM). Theoretical discussion and numerical results will be presented to show that the CDM can maintain second-order accuracy throughout the computational domain.     

Surface Finish Effects on High-Speed Signal Degradation

In high-speed circuits, skin effects and dielectric properties are important factors for signal degradation considerations, especially in the microwave frequency region. When surface finishes are applied to prevent traces from oxidation, the electrical properties of traces are affected. In this work, experimental study and finite element method (FEM) based full wave simulation are used to investigate the effects of hot air solder leveling (HASL) and its alternatives on signal integrity. Classical interconnect structures, microstrip line, and differential mode coupled microstrip lines subjected to different finishes are investigated. Our work reveals that the net conductor loss that results from surface finishes is the dominant factor in signal degradation when the clock frequency is within the microwave frequency region. For microstrip line, the influence of surface finishes on signal distortion is negligible; for differential mode coupled microstrip lines, however, the surface finish effects, especially those with high resistivity, can lead to significant signal distortions. These findings are expected to have strong implications when designing high-speed circuits that meet strict timing requirements.     

On the fourth order finite screw system: general displacement of a point in a rigid body

Summary In this paper, the displacement of a point on a rigid body which moves from one spatial position to another is considered by the concept of screw matrix. Since there are ³ possible screws to achieve such displacement, using Parkin's definition (measure) for pitch, one can represent this infinite set of screws as a 4-system of screws. This has been demonstrated by Huang and Roth by the use of screw triangle [1]. In this paper, however, without any assumption for the expression of pitch we ask the question that whether there exist different appropriate measure of pitch other than Parkin's such that all the available finite screws also form a 4-system. In fact by the use of screw matrix concept, a general expression of the pitch is derived so that the screws realize the stated displacement form a 4-system. It is shown that Parkin's pitch, plus an arbitrary constant, is the only appropriate measure of pitch. To arrive at this conclusion, a special coordinate system is selected. This selection of the coordinate system also makes it possible to yield several new geometrical properties of the set of ³ screws.     

Design,Fabrication and Experimentation of a Deep Drawing Machine

This paper presents the work implemented in designing, fabricating and operating a model of a cheap hydraulic DDM （deep drawing machine）, which is currently utilized in the manufacturing processes lab in the IED （Industrial Engineering Department） at An-Najah National University. The machine is used to conduct different experiments related to the deep drawing process. This work was implemented in three stages： the first was the design stage, in which all design calculations of the DDM elements were completed based on the specifications of the product （cup） to be drawn; the second was the construction stage, in which the DDM elements were fabricated and assembled at the engineering workshops of the university; the last was the operating and experimentation stage, in which the DDM was tested by conducting different experiments. The experience gained from designing and constructing such a mechanical lab equipment was found to be successful in terms of obtaining practical results that agree with those available in literature, cost-effective relative to the cost of a similar purchased equipment, as well as enhancing students＇ abilities in understanding the deep drawing process in particular and machine elements design concepts in general.     

A simple finite-difference frequency-domain (FDFD) algorithm for analysis of switching noise in printed circuit boards and packages

Simultaneous switching noise (SSN) compromises the integrity of the power distribution structure on multilayer printed circuit boards (PCB). Several methods have been used to investigate SSN. These methods ranged from simple lumped circuit models to full-wave (dynamic) three-dimensional Maxwell equations simulators. In this work, we present an efficient and simple finite-difference frequency-domain (FDFD) based algorithm that can simulate, with high accuracy, the capacity of a PCB board to introduce SSN. The FDFD code developed here also allows for simulation of real-world decoupling capacitors that are typically used to mitigate SSN effects at sub 1 GHz frequencies. Furthermore, the algorithm is capable of including lumped circuit elements having user-specified complex impedance. Numerical results are presented for several test boards and packages, with and without decoupling capacitors. Validation of the FDFD code is demonstrated through comparison with other algorithms and laboratory measurements.     

Simultaneous switching noise mitigation in PCB using cascaded high-impedance surfaces

A novel concept for ultra-wide-bandwidth suppression of simultaneous switching noise (SSN) in high-speed printed circuit boards (PCBs) is proposed and implemented. This method consists of cascading high-impedance surfaces (HIS) with different stop bands, creating rejection over a wide frequency region. A PCB with the cascaded HIS design has been successfully fabricated and tested.     

Novel Planar Electromagnetic Bandgap Structures for Mitigation of Switching Noise and EMI Reduction in High-Speed Circuits

Planar electromagnetic bandgap (EBG) structures with novel meandered lines and super cell configuration are proposed for mitigating simultaneous switching noise propagation in high-speed printed circuit boards. An ultrawide bandgap extending from 250 MHz to 12 GHz and beyond is demonstrated by both simulation and measurement, and a good agreement is observed. These perforated EBG-based power planes may cause spurious and unwanted radiation. In this paper, leakage radiation through these imperfect planes is carefully investigated. It is found that the leakage field from these planar EBG structures is highly concentrated around the feed point, and the field intensity is attenuated dramatically when passing across several periods of patches. A novel concept of using these EBG structures for electromagnetic interference reduction is also introduced. Finally, the impact of power plane with EBG-patterned structures on signal integrity is studied.     

Frequency-domain complementary operators for finite-elementssimulation

A new mesh-truncation technique is introduced for the frequency-domain (time-harmonic) solution of open-region radiation problems. The technique is based on the complementary operators method (COM), where two independent solutions are averaged to eliminate first-order boundary reflections. The dual complementariness in the frequency domain is achieved by introducing a discrete-domain operator that achieves the objective of ∂_t in the original time-domain development of COM