Modeling Effects of Random Rough Interface on Power Absorption Between Dielectric and Conductive Medium in 3-D Problem

We study the effects of a random rough surface on the power absorption between a dielectric and conductive medium in a 3-D configuration where the surface height varies in both horizontal directions. The analytic small perturbation method of second order and numerical T-matrix method are used. The absorption depends on the root mean square height, correlation length, and correlation function of the random rough surface. A closed-form expression of power absorption enhancement factor is obtained from small perturbation method of second order. Results show that the T-matrix method agrees with the small perturbation method for rough surfaces with a small slope. We further compare the 3-D results to the previous 2-D results and show significant difference. The power absorption enhancement factor exhibits saturation for the Gaussian correlation function, but not for the exponential correlation function     

Applications of dense media radiative transfer theory for passivemicrowave remote sensing of foam covered ocean

The effect of the foam covered ocean surface on the passive microwave remote sensing measurements is studied based on the electromagnetic scattering theory. In formulating an electromagnetic scattering model, the authors treat the foam as densely packed sticky air bubbles coated with thin seawater coating. The layer of foam covers the ocean surface that has air bubbles. They then use dense media radiative transfer (DMRT) theory with quasi-crystalline approximation (QCA) for densely distributed sticky moderate size particles to calculate the brightness temperatures of the foam-covered ocean surface. Results are illustrated for 19 GHz and 37 GHz and for both vertical and horizontal polarizations as a function of foam microstructure properties and foam layer thickness. Comparisons are also made with experimental measurements     

Junction breakdown instabilities in deep trench isolationstructures

Junction breakdown voltage instability in a p-n junction formed in bulk silicon adjacent to a deep trench filled with polysilicon was investigated. The structure investigated consists of a 5-μm-deep trench filled with heavily p-doped polysilicon. The trench is open at the bottom and is consequently shorted to the p-substrate. The time-dependent behavior of the walkout or the breakdown voltage instability is similar to that reported for planar p-n junctions terminating on surface oxide. Results suggest that trapping of holes in the trench sidewall dielectric is responsible for this phenomenon. The product of trapping center concentration and capture cross section N σ is estimated to be 90 cm^-1     

The Effects of Transmitter/Receiver Clock Time-Base Instability on Coherent Communication System Performance

The purpose of this paper is to present a model and associated analysis of the deleterious effects which both transmitter and receiver data clock time-base instability have on bit-error probability. The types of time-base instability modeled and analyzed include what is commonly referred to as bit jitter (epoch jitter), bit-jitter rate (time interval jitter), and data asymmetry. The biterror probability is determined as a function of the statistical characteristics of the time-base instability, the data-transition density, the signal-to-noise ratio in the bit-rate bandwidth and the mechanizations of both the data-bit detector and bit synchronizer. The latter is manifested through the bit synchronizer's natural frequency and loop-damping parameters. Numerical results which indicate the sensitivity of the system bit-error rate to various parameters of the model are provided.     

Performance Analysis of Digital Integrate-and-Dump Filters

Key design parameters associated with the operation of a digital integrate-and-dump filter are identified in this paper. Performance degradation effects associated with the selection of these parameters such as analog-to-digital converter (ADC) gain loading factor, number of bits used, predetection bandwidth, sampling rate, and accumulator length are considered. Numerical results of practical interest are also provided.     

Lightweight,Superelastic Boron Nitride/Polydimethylsiloxane Foam as Air Dielectric Substitute for Multifunctional Capacitive Sensor Applications

Porous polymeric foams as dielectric layer for highly sensitive capacitive based pressure sensors have been extensively explored owing to their excellent flexibility and elasticity. Despite intensive efforts, most of previously reported porous polymer foams still suffer from difficulty in further lowering the attainable density limit of ≈0.1 g cm^?3 while retaining high sensitivity and compressibility due to the limitations on existing fabrication techniques and materials. Herein, utilizing 3D interconnected networks of few‐layer hexagonal boron nitride foams (h‐BNFs) as supporting frameworks, lightweight and highly porous BN/polydimethylsiloxane composite foams (BNF@PDMS) with densities reaching as low as 15 mg cm^?3 and permittivity close to that of air are fabricated. This is the lightest PDMS‐based foam reported to date. Owing to the synergistic effects between BN and PDMS, these lightweight composite foams possess excellent mechanical resilience, extremely high compressibility (up to 95% strain), good cyclic performance, and superelasticity. Being electrically nonconductive, the potential application of BNF@PDMS as a dielectric layer for capacitive sensors is further demonstrated. Remarkably, the as‐fabricated device can perform multiple sensing functions such as noncontact touch sensor, environmental monitoring sensor, and high sensitivity pressure sensor that can detect extremely low pressures of below 1 Pa.     

A 1.8-V distributed voltage-controlled oscillator module for 5.8-GHz ISM band

This letter presents the design and implementation of a 1.8-V 5.8-GHz distributed voltage-controlled oscillator module based on bipolar transistors. The oscillator delivered -2-dBm-output power with a current consumption of 11.5 mA. The tuning range achieved was 650 MHz. The measured phase noise was -100 dBc/Hz at 1-MHz offset. The circuit construction was simple and robust and no buffer amplifier was needed. The design can be used for 5.8-GHz ISM band wireless LAN applications.     

Autotuning of phase-lead controller for integrating systems

In this paper, a new method for autotuning of a phase-lead controller for nonselfregulating or integrating systems is proposed. By connecting the system with a suitable high-order derivative filter and a relay with hysteresis, the frequency data of the system can be obtained and phase-lead controllers can be designed based on some phase margin specifications. Simulations and experimental studies are included in the paper to illustrate the performance of the proposed algorithm     

Two-Dimensional Adaptive Decimation and Interpolation Scheme for Low Bit-Rate Image Coding

A novel image compression scheme based on two-dimensional adaptive decimation is reported in this paper. In this approach, images are encoded with adaptive sampling along the horizontal and vertical directions, and decoded with an edge prediction interpolation algorithm. The method is capable of maintaining reasonable coding fidelity at low bit-rate with good visual quality. As only a small amount of computation is required in the encoding and decoding processes, the compression scheme can be implemented for real time operation with simple hardware and a small amount of memory storage. The proposed scheme had been applied in encoding images at bit-rates between 0.2 and 0.33 bpp and the results are encouraging.     

Earliest Deadline First Scheduling with Active Buffer Management for Real-Time Traffic in the Internet

We studied the problem of QoS guarantee for differentiated services. A two-level hierarchical scheduling framework was deployed to separate QoS metrics. Due to its desirable property of minimizing the maximum packet lateness, the Earliest Deadline First (EDF) scheduling was adopted to provide the in-class scheduling for the time-sensitive traffic. We employed an EDF scheduler combined with an active buffer management scheme (CHOKe) to improve the fairness of resource allocation and to maintain a good delay performance for real-time applications. Simulation results showed that the proposed scheme can achieve a better delay performance and make a more fair bandwidth allocation between the real-time TCP and UDP connections than the First Come First Served (FCFS) scheduling with the drop-tail buffer management which is commonly deployed in traditional IP routers.