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A novel design of trapeizform U-slot folded patch feed antenna is presented in this paper. It is optimized by an evolutionary based optimization scheme which is capable of producing an antenna design that has a wide impedance bandwidth but small in dimension size. The optimized design was also experimentally verified by its hardware prototype in which 101.3% measured impedance bandwidth (VSWR [less than or equal to] 2) was obtained compared with its simulated bandwidth of 104%. Also, both the effectiveness of the optimization methodology and the proposed antenna configuration have been justified through comparison results. Index Terms--Antennas, genetic algorithms, optimization methods.

A physical-based analytical model for on-chip spiral inductors with accurate substrate modeling is developed. This generic model can be applied to various substrate resistivities and can also facilitate the design and optimization of on-chip inductor for radio-frequency (RF) IC applications.

The diagonally perturbed incomplete factorization preconditioning scheme is applied to the conjugate gradient (CG) method fur solving a large system of linear equations resulting from the use of edge-based finite-element method (FEM). This scheme contains more global information about the coefficient matrix when compared with banded-matrix schemes. The efficient implementation of this preconditioned CG (PCG) algorithm is described in detail for complex coefficient matrix equation. On several electromagnetic problems the PCG approach converges in CPU time, which is 8.6-19.5 times shorter with respect to the CG approach. By comparison with other preconditioned techniques, the results demonstrate that incomplete factorization preconditioning strategy is especially effective for CG iterative method when edge-FEM is applied to solve large-scale time-harmonic electromagnetic field problems. Index Terms--Conjugate gradient (CG) method, finite-element method (FEM), incomplete factorization, preconditioning technique.

The problem of electromagnetic scattering by three-dimensional dielectric bodies is formulated in terms of a weak formulation of the domain-integral equation. Applying Galerkin's method with rooftop functions as basis and testing functions, the integral equation can be solved by the Krylov-subspace iterative fast Fourier transform (FFT) methods. However, poor convergence is observed when the relative perimittivity of the scatterer becomes large. In order to relieve this trouble, an augmented generalized minimum residual method (AGMRES) is presented. Comparisons between several typical iterative methods are made to show the efficiency of our proposed method. Index Terms--Augmented generalized minimum residual method (AGMRES), electromagnetic wave scattering, fast Fourier transform (FFT), Krylov-subspace iterative methods.

A hybrid scheme that incorporates the method of finite elements, the method of lines, variational techniques, and conformal mapping is proposed for the analysis of guided-wave structures. This technique is devised to analyze complex waveguide structures with irregular composite geometries, High numerical accuracy is maintained by treating key singularities by semianalytical procedures. Compared with the conventional method of lines with finite difference techniques, the proposed scheme is able to solve many complex guided-wave problems with fewer mesh lines without compromise on accuracy. This gain is due to the added variable mesh-directions and the flexibility in the method of finite elements in choosing appropriate functions for fitting the configuration of concern. Index Terms--Guided-wave problems, method of finite elements, method of lines, variational analysis.

An efficient algorithm for wave scattering from two-dimensional lossy rough surfaces is proposed. It entails the use of a single magnetic field integral equation (SMFIE) in conjunction with a multilevel sparse-matrix canonical-grid (MSMCG) method. The Rao-Wilton-Glisson (RWG) triangular discretization is adopted to better model the rough surface than the pulse basis functions used in the well-established SMCG method. Using the SMFIE formulation, only one unknown per interior edge of the triangular mesh approximating the rough surface is required, and the iterative solution to the moment equation converges more rapidly than that of the conventional coupled equations for dielectric rough surfaces. The MSMCG method extends the applicability of the SMCG method to rougher surfaces. Parallel implementation of the proposed method enables us to model dielectric surfaces up to a few thousand square wavelengths. Simulation results are presented as bistatic scattering coefficients for Gaussian randomly rough surfaces. Index Terms--Multilevel sparse-matrix canonical-grid method (MSMCG), Rao-Wilton-Glisson (RWG) triangular basis, rough surface scattering, single magnetic field integral equation (SMFIE).

A study was conducted to analyze the physical mechanism underlying shot-noise-induced excess low-frequency noise in floating-body partially depleted silicon-on-insulator metal oxide semiconductor field effect transistors. Two noise sources related to the conducting channel were examined. Results indicated a characteristic frequency in noise spectrum and ac output impedance of the transistors.

A study of air pollution data over the Great Lakes region as collected by the Integrated Atmospheric Deposition Network showed atmospheric loading of pollutants to the Great Lakes consisted of seven organochlorine pesticides, four polychlorinated biphenyl species, four polycyclic aromatic hydrocarbons and four trace metals. Loading rates of the different compounds were not determined since atmospheric loading was equal to air-water equilibrium.

InGaAs/GaAs (111)B quantum well p-i-n structures grown through gas source molecular beam epitaxy were studied through photoreflectance spectroscopy. The built-in electric field was determined from the above band-gap Franz-Keldysh oscillations (FKOs) by employing the reduced mass deduced from experiments. The strain-induced piezoelectric field was then obtained directly from the comparison of the periods of FKOs in various samples.

With the advent of the microwave radiometer, passive remote sensing of clouds and precipitation has become an indispensable tool in a variety of meteorological and oceanographical applications. There is wide interest in the quantitative retrieval of water vapor, cloud liquid, and ice using brightness temperature observations in scientific studies such as earth's radiation budget and microphysical processes of winter and summer clouds. Emission and scattering characteristics of hydrometeors depend on the frequency of observation. Thus, a multifrequency radiometer has the capability of profiling cloud microphysics. Sensitivities of vapor, liquid, and ice with respect to 20.6, 31.65 and 90 GHz brightness temperatures are studied. For the model studies, the atmosphere is characterized by vapor density and temperature profiles and layers of liquid and ice components. A parameterized radiative transfer model is used to quantify radiation emanating from the atmosphere. It is shown that downwelling scattering of radiation by an ice layer results in enhancement at 90 GHz brightness temperature. Once absorptive components such as vapor and liquid are estimated accurately, then it is shown that the ice water path can be retrieved using ground-based three-channel radiometer observations. In this paper we developed two- and three-channel neural network-based inversion models. Success of a neural network-based approach is demonstrated using a simulated time series of vapor, liquid, and ice. Performance of the standard explicit inversion model is compared with an iterative inversion model. In Part II of this paper, actual radiometer, and radar field measurements are utilized to show practical applicability of the inverse models.

A hybrid evaluation method using both the spectral- and the spatial-domain techniques is proposed for the evaluation of the Sommerfeld-type integrals resulting from the full-wave analysis of microstrip structures. This method combines the advantages of the spectral-domain for the evaluation of near fields and the spatial-domain method for the evaluation of far-fields. This method is simple and needs no additional formulations. It also provides an easy alternative method to handle the inefficiency of calculation with the singularity of the Green's function. Numerical results are used to demonstrate the simplicity and the accuracy of this method. Index Terms--Full-wave analysis, hybrid evaluation method, microstrip structure, Sommerfeld's integral.

Several measurements are conducted to determine the temperature-dependent photoconductivity that is exhibited by the various [beta]-[In.sub.2][S.sub.3] single crystals. The origin, as well as the mechanism of all the defect states present in the crystals are also analyzed.

A silicon diverging beam modulator made partly from metal-oxide-silicon process modules and using the mode modulation technique was presented. Modulator efficiency was greatly determined by the core width and the driving current. Higher modulation efficiency was obtained when core width was narrower and driving current was high. The modulator was found to be compatible with silicon microelectronics technology.

The temperature-dependent surface photovoltage spectroscopy (SPS) technique is employed to explain the characterization of the highly strained InGaAs/GaAs double quantum well (DQW) structures. The band lineup and several other properties of the structures are also analyzed.

Surface photovoltage (SPV) and photoluminescence excitation (PLE) spectroscopy are used for characterizing multiple stacked self-assembled InAs quantum dot (QD) structures with and without InGaAs overgrown layers. The spectra feature situated between the highest lying QD state and the wetting layer (WL) signals are attributed to the electronic transition in the InAs/InGaAs dots-in-well structure.

An investigation on the multilayer self-assembled InAs/GaAs quantum dot (QD) structures with varying GaAs spacer layer (SL) thickness is conducted using surface photovoltage spectroscopy (SPS) and photoluminescence (PL). The transition blueshifted with a decrease of the SL thickness indicates that the materials intermixing between InAs QDs and GaAs SL are strongly driven by strain.