Geometrical analyses of basic equations of electromagnetics waves propagation in anisotropic dielectric materials with magnetic isotropy are presented in two complementary papers (Part I and Part II). In the present one, analysis arises from quadrics associated with relative dielectric tensor (ε) compatible with conical surfaces that represent the general plane wave equation (relation of dispersion). This study systematizes rays propagation in left-handed materials (LHMs) exhibiting dielectric anisotropy and magnetic isotropy. In particular, indefinite dielectric media where dielectric permittivities are not all the same sign, have been investigated. Graphical alternative procedures for ray tracing in these media are presented.

Asymptotic techniques have been successfully applied to compute electromagnetic wave radiation in various high-frequency engineering domains. Recent approaches based on Gaussian beams for tracking fields may overcome some problems inherent to the ray methods such as caustics. The efficiency of these methods is based on the ability to expand surface fields into a superposition of Gaussian beams. However, some difficulties may arise when the surface is curved. In this paper, we propose a new efficient way to expand fields on a curved surface into Gaussian beams. For this purpose, a new beam formulation called Conformal Gaussian Beam (CGB) is used. The CGBs have been developed to overcome the limitation of the expansion into paraxial Gaussian Beams. The analytical Plane-Wave Spectrum and far-field of a CGB are derived and compared with numerical calculations. A brief parameter analysis of the CGBs is realised.

Geometrical analysis of basic equations of electromagnetics waves propagation in anisotropic dielectric materials with magnetic isotropy are presented in two complementary papers (Part I and Part II). In this paper, analysis arises from local properties of dielectric permittivity tensor and Mohr's plane graphical construction compatible with circumferences that represent general plane wave equation. This theoretical study allows to know how rays propagate in left-handed metamaterials (LHMs) exhibiting dielectric anisotropy and magnetic isotropy. Geometrical analysis yields plane graphical procedures for ray tracing, that are extremely easy. In particular, indefinite dielectric media, where dielectric permittivities are not all the same sign, has been investigated and a joint study of materials having the same eigenvalues of ε, but with opposite values of μ_r is performed. The opposite sense of propagation of rays in "opposite media" (media with opposite values of ε_i and μ_r) has been also shown. It must be pointed out that the presented method always allows graphical plane constructions, even when dealing with biaxial media.

A hybrid empirical-neural (HEN) model, to account for a loading effect of arbitrary raised dielectric slab in a microwave cylindrical metallic cavity, is presented. It is based on combination of an approximate model, as a rough empirical knowledge holder, and multi-layer perceptrons (MLP) neural network. In comparison with the model based only on MLP network, more accurate and efficient resonant frequencies calculation is achieved.

It is proposed that the application of defected ground structures (DGS) and electromagnetic bandgap (EBG) reduce the phase velocity, increase effective permittivity of microstrips and reduce the effective the wavelength which eventually lead to the reduction of overall length of Wilkinson power dividers. Furthermore, the adjacent strip lines may approach each other, which cause coupling problems. The undesired coupling maybe cancelled by connecting a capacitance in parallel with the isolation resistor of Wilkinson power divider. Application of DGS and EBG will not only reduce the dimensions of the divider, but also improves its scattering parameters.

Cyclic delay diversity (CDD) is a simple approach to increase the frequency selectivity of the channel in an orthogonal frequency division multiplexing (OFDM) based transmission scheme. However, CDD can cause serious degradation in the performance of channel and frequency estimation in the frequency domain. This paper suggests a post-FFT frequency estimation scheme suitable for arbitrary cyclic delays in the CDD-OFDM system. By partitioning uncorrelated pilot subcarriers into subsets to be flat, and performing frequency estimation for each pilot subset, a robust integer frequency offset estimation scheme is derived.

A technique for natural frequency extraction without a prior knowledge of the number of natural frequencies is proposed. The proposed scheme is based on the GPOF method with the overestimated number of natural frequencies, and it has been shown from simulation result that the proposed method is superior to the GPOF method. The method is applied to the extraction of the natural frequencies of the thin wires whose exact natural frequencies are known. While the absence of the true natural frequency has much effect on the transient response reconstruction, the absence of the spurious natural frequency has little effect on the transient response reconstruction. Using the above property, true natural frequencies and spurious natural frequencies can be discriminated.

Current driven electrostatic ion cyclotron instability has been studied for parallel flowv elocity shear with perpendicular a.c. electric field to the ambient magnetic field for bi-Maxwellian density drift distribution function. The method adopted for expression for dispersion relation and growth rate is kinetic approach and method of characteristic solution for ionospheric plasma. The effect of a.c. frequency, density gradient, and velocity shear scale length has been discussed.

A 2×2 quasi-Yagi antenna array fed by a novel orthogonal T junction is presented. The orthogonal T junction is constructed with a traditional microstrip T junction, two planar microstrip to CPW transitions and two orthogonal microstrip to CPW transitions. The orthogonal T junction can be integrated with the quasi-Yagi array element directly. A 2×2 prototype operated from 7.6 GHz to 12 GHz is fabricated and measured.

Turbo equalization is applied to microwave channel in this paper, and we bring forward an improved Turbo equalization algorithm named Max-Log-Map. A simulation based on a given microwave fading channel has been made. The results show that performances are close to each other between improved TE-Max-Log-Map and Log-Map, and the coding gain is 1 dB at 10^-4 of BER compared with Max-Log- Map. The improved Max-Log-Map method improves the reliability of microwave communication.

There are various techniques for the deposition of SiO₂ films on silicon. Flame Hydrolysis Deposition (FHD) techniques is the most economical technique for the deposition of SiO₂ films. In this technique the SiO₂ films are deposited by hydrolysis of SiCl₄ in a high temperature H₂-O₂ flame. In the present study we present the growth of SiO₂ films by indigenously developed FHD system and organic compound Tetraethoxyorthosiliate/Tetraethoxysilane TEOS as source of silicon. The films deposited by the FHD system are porous and need annealing at higher temperatures for the densification. We present here for the first time direct dense glassy transparent SiO₂ films deposited by our FHD system. The optical properties of the deposited films were studied by ellipsometery. FTIR spectroscopy was carried out to study the various characteristic peaks of SiO₂ bonds. The peaks corresponding to Si-O-Si stretching, bending and rocking modes are observed at 1090 cm^-1, 812 cm^-1 and 463 cm^-1 respectively. The absence of peaks corresponding to the OH bond in the deposited film reveals that the deposited films are most suitable for the photonic devices application. The surface analysis was carried out using SEM. The EDAX of the deposited film confirms the composition of the Si and O in the deposited film.

In this paper, a compact design and construction of microstrip Ultra Wide Band (UWB) antenna is proposed. The proposed antenna has the capability ofop erating between 4.1 GHz to 10 GHz. The antenna parameter in frequency domain analysis have been investigated to show its capability as an effective radiating element. Furthermore, time domain Gaussian pulse excitation analysis in UWB systems is also demonstrated in this paper. As a result, the simulation results demonstrated reasonable agreement with the measurement results and good ultra-wideband linear transmission performance has also been achieved in time domain.

In this paper, we present a new domain decomposition technique which considers the effect of multiple reflections between the subdomains. This method has the ability to simulate accurately large electromagnetic problems that are difficult to handle using the direct application of the FDTD method. The results for the test examples considered in this paper compare well with the direct FDTD solution, and serve to validate the proposed scheme.

A class of linear derivative constraints, which provides robustness to the conventional narrowband uniform linear array configuration so as to handle broadband and moving jammer sources problem is presented. The robust modification of linear constrained minimum variance (LCMV) algorithm is given to broaden the null widths in the jammer directions. Numerical results show that the proposed algorithm has a better performance in broadband and moving jammer scenarios in terms of maintaining beamwidth broadening and capability of rejecting interferences.

In this paper we formalizes a new discrete time model of digital array based MIMO radar in which the combined effects of the transmit filter, physical MIMO multi-path channel fading, and receive filter. It has the same sampling period as that of the MIMO receiver. Apart from this, SNR value and target detection are different in compared to the continuous domain nature. Orthogonality is introduced using OSTBC (orthogonal space time coding) including interelement spacing at the transmitter is greater than the target beam width coverage. For space and temporal diversity we have considered distributed source model. and modulation schemes respectively. Frequency diversity is achieved using N point IFFT (N = 32, 64, 256, 1024) at the base band. Thus, three dimensional analysis with respect to diversity and selective nature of fading channel in digital array based MIMO radar are now used for performance analysis based on probability of detection, symbol error rate, model error, power spectral density at the receiver and SNR value at the detector.

Planar multilayer structures have found several applications in electromagnetics. In this paper, an equivalent model based on the bi-characteristic-impedance transmission line (BCITL) is employed to model planar multilayer structures effectively for both lossless and lossy cases. It is found that the equivalent BCITL model provides identical results, for both perpendicular and parallel polarizations, as those obtained from the propagation matrix approach.

A fast analysis of aperture-coupled reflectarrays is presented in this work in terms of transmission line model. The circuital approach is adopted to derive the phase design curve as a function of the current flowing on the equivalent impedance of the single radiating element. Computational costs are drastically reduced with respect to standard full-wave methods. Numerical and experimental validations are discussed on slot-coupled reflectarray configurations working at different operating frequencies.

This paper presents microstrip transmission lines for designing a microstrip open loop resonator bandpass filter and a novel dual band transmitter. Microstrip open loop resonator bandpass filter with the dumbbell DGS under feed lines enhances the harmonic suppressed at the center frequency of 2.44 GHz. An asymmetric dumbbell DGS-integrated microstrip line is applied to the dual band transmitter which performs as a frequency doubler at 6.8 GHz or a power amplifier at 2.4 GHz. For the proposed bandpass filter,it has a wide stopband characteristic with attenuation -25 dB up to 8 GHz and has an -1.25 dB insertion loss by using two dumbbell DGS. Measurements of the dual band transmitter show that in frequency double mode,fundamen tal suppression and maximum output are -41 dBc and 7.8 dBm. And in amplifier mode,second harmonic suppression,P1 dB and gain achieve -52.6 dBc,13.7 dBm and 16.5 dB, respectively.

A numerical method is presented for determining the static charge distribution and capacitance of a round disk capacitor. Based on equivalent surface charge distributions, an integral equation subject to the boundary conditions is transformed into an algebraic equation by using the method of moments. In the proposed scheme to eliminate the discretizing errors often encountered in other techniques, annular patch subdomains are introduced, not only to improve the accuracy of solutions, but also to reduce the matrix size of the resultant equation. By solving the transformed algebraic equation, the charges per unit area on the interfaces are numerically determined. With use of the free charge on plates obtained by using annular patches, the capacitance is more accurately calculated. The equipotential lines around a round disk capacitor are also calculated. In order to show the usefulness of this method, the employed scheme is applied to a single circular disk with an exact solution, and to the dielectric filled capacitor partially covered by plates. Those results are examined and discussions are also made to support the validity of the presented scheme.

Design of a compact dual frequency microstrip antenna is presented. The structure consists of a slotted circular patch with a dielectric superstrate. The superstrate, not only acts as a radome, but improves the bandwidth and lowers the resonant frequency also. The proposed design provides an overall size reduction of about 60% compared to an unslotted patch along with good efficiency, gain and bandwidth. The polarization planes at the two resonances are orthogonal and can be simultaneously excited using a coaxial feed. Parametric study of this configuration showed that the frequency ratio of the two resonances can be varied from 1.17 to 1.7 enabling its applications in the major wireless communication bands like AWS, DECT, PHS, Wi.Bro, ISM, and DMB. Design equations are also deduced for the proposed antenna and validated.