An all-optical microwave generation using a multiwavelength photonic crystal fiber Brillouin laser is presented. A highly nonlinear photonic crystal fiber with the length of 25m is used as Brillouin gain medium. A Fabry-Perot cavity with two fiber Bragg gratings as reflectors are designed in order to enhance the Brillouin conversion efficiency. The fiber Bragg gratings can be used to selectively excite the jth-order Stokes' wave and suppress other order Stokes' waves. The mechanism for microwave/millimeterwave generation is theoretically analyzed. In the experiment, both 9.788 GHz and 19.579 GHz microwave signals are achieved through mixing the pump wave with the first-order and the second-order Stokes' waves.

The electromagnetic scattering from a conducting object coated with metamaterials, which have both negative permittivity and permeability is derived rigorously by using finite difference frequency domain (FDFD). A formulation for the FDFD method is presented. The scattering from circular and multilayers elliptic cylinder coated by metamaterial are investigated. Also, the scattering from dielectric and metamaterial sphere is depicted. Numerical results are compared with the available data in the literature.

A proposed sensor for landmines detection consists of two parallel microstrip antennas placed on the same ground plane and with corrugated ground surface between the arrays has been investigated. The microstrip patch array with corrugated ground surface has the advantage of a low mutual coupling compared with the classic arrays. The Finite-Difference Time-Domain (FDTD) is used to simulate the sensor for landmines detection.

In this paper, three analytic closed form solutions are introduced for arbitrary Nonuniform Transmission Lines (NTLs). The differential equations of NTLs are written in three suitable matrix equation forms, first. Then the matrix equations are solved to obtain the chain parameter matrix of NTLs. The obtained solutions are applicable to arbitrary lossy and dispersive NTLs. The validation of the proposed solutions is verified using some comprehensive examples.

A simple and inexpensive method for the qualitative characterization of wood surfaces is presented. It is based on the iterative autocorrelation of laser speckle patterns produced by diffuse laser illumination of the wood surfaces.The method exploits the high spatial frequency content of speckle images. A similar approach with raw conventional photographs taken with ordinary light would be very difficult. A few iterations of the algorithm are necessary, typically three or four, in order to visualize the most important periodic features of the surface. The processed patterns help in the study of surface parameters, to design new scattering models and to classify the wood species.

Improving the performance of a microstrip antenna array has been considered based on the innovative use of an absorbing radar cover.Since the surface wave between antennas array elements plays a major role in mutual coupling and scattering behavior of array antenna. The main objective of this work is to reduce the effect of surface wave between array elements using radar absorbing cover.The absorbing cover has been designed with spatial configuration to get maximum performance at the resonant frequency of the fabricated microstrip antenna array.The measured results of the tested antenna array show a significant reduction of both mutual coupling between array patches and radar cross section of the tested antenna array with minimum side effects on the antenna parameters.

Setting up ground based antennas for operation in the HF and longer wavelength bands frequently involves clearing large areas of land for the installation of ground mats to provide a high conductivity return path for the displacement currents. In moving from the cleared area to the virgin scrubland beyond, which is assumed to be forested with bushes and small trees, there is the possibility of an abrupt change in surface properties at the boundary resulting from the discontinuity in the vegetation which at longer wavelengths can be modelled as a change in surface impedance. By modelling the trees and bushes as point dipole moments, the aim of this paper is to estimate the significance of any such effect in terms of the gross physical properties of the vegetation. The result is to show that in normal circumstances the effect can be expected to be slight. A solution to this problem has application in helping determine the environmental footprint of the antenna installation, the amount of land that needs to be cleared to satisfactorily accommodate it.

Based on both the modified Rytov method and the altitude-dependent model of the ITU-R slant atmospheric turbulence structure constant, the uniform model of scintillation index considering inner- and outer-scales is derived form weak to strong fluctuation regions with Gaussian beam propagation on the slant path, and can be degenerated to the result of the horizontal path with atmospheric structure constant is a fixed value. The numerical conclusions indicate the smaller wavelength, the inner-scale has a stronger impact on scintillation than outer-scale. But, in strong fluctuation, the outerscale effect is prominence. Finally, the numerical results are compared and verified with the experimental data.

In this paper two multi-clad RI- and RII-type optical fiber structures for small dispersion and dispersion slope as well as large bandwidth are considered and novel design strategy for this purpose is presented. The suggested design method uses the Differential Evolution (DE) approach. We put absolute value of dispersion factor as fitness function in differential evolution method. This algorithm successfully introduces a special fiber including so small dispersion and dispersion slope in the predefined wavelength duration. Also, the proposed method can set zero dispersion wavelengths with high accuracy compared other traditional methods. The designed dispersion-shifted RI single-mode fiber has the bandwidth of 600nm and the max amount of 1.36 (ps/km/nm) in that duration which is an ideal result.

Spatial focusing characteristics of time reversal (TR) electromagnetic waves are studied in this paper. Different antenna arrays are used as a TR mirror and their elements are arranged in one and two dimensions in the horizontal plane. The focused energy density around initial source location is investigated in non-line-ofsight (NLOS) and line-of-sight (LOS) cases, respectively. The results demonstrated that, roughly speaking, under the case of fixed space between two adjacent elements, the more the number of the array elements, the stronger the focused average energy density. However, in the case of fixed TR mirror array aperture, some abnormal phenomena are observed when additional elements are inset into the initial one.

The paper presents the faster, simpler, and accurate algorithm to solve time independent Schrodinger equation based on transfer matrix method. We can thus calculate all bound and quasi bound energy and the corresponding probability density. A central part of this paper deals with the solving of Schrodinger equation for quantum well structure. Our results show that the transfer matrix method is accurate, it is easier to implement. The increase in well width increases the FWHM from 5.4 nanometer to 9.4 nanometer, while the increase in the Aluminum concentration the FWHM decreases from 8.98 to 5.4.

The enigma of the wave-particle duality of photon has remained unimpressively explained for a century since Einstein presents the concept of the photon in 1905. This article establishes a classical geometric structure model of a single photon based on field matter, educes a formula for the size of a photon; assumes that there only are two kinds of photon of right hand and left hand circular polarized, and suggests the frequency ω of photon polarization rotated to be its spin frequency. It ascribes the wavelike of photon to its spin motion and the particle-like to its translation motion. From the point of photon particle instead of wave view to re-analyze Young's double-slit interference and polarizer experiments, gives reasonable mechanism. It defines the phase velocity and the group velocity of a photon. It gives a unified and consistent understanding of quantum particle of light and classical electromagnetic waves field. Evidently, such a precisely defined conceptual model is reasonable, objective and easy to accept for classical physicists.

A phase-alignment system is used fully integrate a power amplifier, Cartesian feedback linearization circuitry, and a phasealignment system. The phase-alignment system employs a new technique for offset-free analog multiplication that enables it to function without manual trimming. This paper demonstrates how the phase-alignment system improves the stability margins of the fully integrated Cartesian feedback system. The power amplifier itself, integrated on the same die, operates at 1 GHz and delivers a maximum of 30 dBm of output power into a 50-load. The class AB design for open loop and close loop power amplifier with Cartesian feedback, demonstrated a good linearity of 50 dBc and 80 dBc, respectively. The operating power is 2 W at 1000 MHz frequency.

In this paper a complete analysis to the stability of a microwave oscillator with distributed element resonator is presented. In this type of oscillators, the circuit description changes form ordinary differential equations to partial deferential equations. In this paper a Gunn diode oscillator with distributed elements resonator is analyzed. The instability condition of the startup phase and the stability condition of the steady state oscillation is investigated.

In this paper, a Medium Access Control (MAC) protocol is proposed to investigate Quality of Service (QoS) for multimedia traffic transmitted over Ultra Wide-Band (UWB) networks and increase the system capacity. This enhancement comes from using Wise Algorithm for Link Admission Control (WALAC) which has three suggested versions. The QoS of multimedia transmission is determined in terms of average delay, admission ratio, loss probability, utilization, and the network capacity. In addition, a new parameter is aroused for the network performance. Comparisons between the IEEE 802.15.3a protocol and the proposed one are done. The proposed protocol shows better results in both sparse and dense networks for real time traffic transmission.

A microstrip 180^o phase shifter obtained by a novel design of Microstrip-to-Coplanar Waveguide (CPW)-to-Microstrip transition is presented. The proposed phase shifter is obtained without changing the layer of the second microstrip line. Via holes are used to transfer the current from the top to the bottom substrate layer and vice versa. The presented phase shifter is operating in a wide bandwidth between 5.5 and 18 GHz, with low insertion loss and reflection coefficients. Because the input and output microstrip lines are on the same layer, the presented phase shifter is suitable for a modified class of feeding networks for phased antenna arrays.

In this paper,a fast integral equation method is developed for extracting the inductances in RF ICs,RF MEMs,IC packages,and deep submicron ICs etc. This method combines a recently developed Multilevel Green's Function Interpolation Method (MLGFIM) [1,2] with the volume integral equation discretized using Volume Loop (VL) basis functions. In it,instead of using the filaments model to simulate the currents flowing in the inductors,w e use the conventional SWG basis functions for this kind of basis functions is flexible for problems with complex geometries. The shortest path finding algorithm is also used to find the source loop basis functions. The inductance extractions from the straight line,the spiral inductors,the bump,and the parallel buses in this paper demonstrate the validity and efficiency of this hybrid method.

Mutual external inductance (MEI) associated with fringing magnetic fields in planar transmission lines is a cause of socalled "ground plane noise", which leads to radiation from printed circuit boards in high-speed electronic equipment. Herein, a Method of Edge Currents (MEC) is proposed for calculating the MEI associated with fringing magnetic fields that wrap the ground plane of a microstrip line. This method employs a quasi-magnetostatic approach and direct magnetic field integration, so the resultant MEI is frequencyindependent. It is shown that when infinitely wide ground planes are cut to form ground planes of finite width, the residual surface currents on the tails that are cut off may be redistributed on the edges of the ground planes of finite thickness, forming edge currents. These edge currents shrink to filament currents when the thickness of the ground plane becomes negligible. It is shown that the mutual external inductance is determined by the magnetic flux produced by these edge currents, while the contributions to the magnetic flux by the currents from the signal trace and the finite-size ground plane completely compensate each other. This approach has been applied to estimating the mutual inductance for symmetrical and asymmetrical microstrip lines.

A deep analysis of the directivity enhancement, due to the insertion of a simple linear antenna into a dielectric EBG, is presented. The operative frequency is chosen near a band-gap edge. The planewave expansion method is used in order to obtain the Bloch dispersion diagrams of infinite two-dimensional EBGs. A rigorous cylindricalwave approach is used to analyze two-dimensional EBGs with finite size, excited by a line source. We apply these tools to the analysis of different emitting devices, and propose solutions to improve their performances.

Discrete complex image method is introduced to get a closed-form dyadic Green's function by a sum of spherical waves. However, the simulation result by the traditional discrete complex image method is only valid in near-field for several wavelengths. In this paper, we analyze the form of spectral domain dyadic Green's function in the whole k_ρ plane and the variety of valid range of simulation results by different sampling paths in two-level discrete complex image method. Consequently, for dyadic Green's function, surface wave pole contribution both in spectral domain and spatial domain is clarified. We introduce the automatic incorporation of surface wave poles in discrete complex image method without extracting surface wave poles. The contribution of surface wave poles in spectral domain and spatial domain dyadic Green's function is further confirmed in the new method. Besides, this method can represent dyadic Green's function by spherical waves in the layer where the source and field points are. So it satisfies the splitting requirement and consequently reduces the computational complexity dramatically especially for objects with large scale in ẑ direction.