In this paper, the angular-diversity radar recognition of ships is given by transformation based approaches with noise effects taken into consideration. The ships and sea roughness are considered by simplified models in the simulation. The goal is to identify the similarity between the unknown target ship and known ships. Initially, the angular-diversity radar cross sections (RCS) from a ship are collected to constitute RCS vectors (usually largedimensional). These RCS vectors are projected into the eigenspace (usually small-dimensional) and radar recognition is then performed on the eigenspace. Numerical examples show that high recognition rate can be obtained by the proposed schemes. The radar recognition of ships in this study is straightforward and efficient. Therefore, it can be applied to many other radar applications.

It is well known that planet Jupiter produces strong radio bursts at decametric wavelengths from regions of temporary radio emission in its magnetosphere. Like the man made radio signals, these signals do interfere in the low frequency radio telescope data while observing a different extraterrestrial source. Identification and characterization of this interfering signal is important in radio astronomy. In most of the radio astronomy sites, spectrum monitoring stations are available for such purposes. These instruments record any strong signal within the band and also aim to locate its position. Depending on the properties of different categories of sources, special modules can be attached to these instruments for obtaining a more detailed picture. These modules can be added at the front end of the instrument using a selector switch and can be connected whenever necessary. Construction of one such module for capturing and recording the Jupiter radio bursts has been described with all the engineering details. It consists of an antenna system followed a receiver (connected to a spectrum recorder). An improvement in the antenna system has been made as compared to the contemporarily available single antenna Jupiter radio telescopes, thereby enabling to record the radio emissions over a larger period using a fixed beam. The receiver system has been designed to process the low frequency Jovian signals from 18 to 25 MHz. The back end is that of a spectrum monitoring system which serves as an automated data analyzer and recorder. It offers flexibility and various setup choices to the user. The mathematical analysis of the instrument and computed system characteristics have been produced in detail for ease of reproductions, direct use in radio astronomy and future design developments.

The lowering and raising operators of cylindrical harmonics are used to derive the general fast multipole expressions of arbitrary order Hankel functions. These expressions are then employed to transform the dense matrix in the scattering matrix method (SMM) into a combination of sparse matrices (aggregation, translation and disaggregation matrices). The novel method is referred to as fast multipole accelerated scattering matrix method (FMA-SMM). Theoretical study shows FMA-SMM has lower complexity O(N^1.5) instead of SMM's O(N²), where N stands for total harmonics number used. An empirical formula is derived to relate the minimum group size in FMA-SMM to the highest order Hankel functions involved. The various implementation parameters are carefully investigated to guarantee the algorithm's accuracy and efficiency. The impact of the cylinders density on convergence rate of iterative solvers (BiCGStab(2) here), memory cost as well as CPU time is also investigated. Up to thousands of cylinders can be easily simulated and potential applications in photonic crystal devices are illustrated.

Yasuura's mode-matching method is employed in the investigation of plasmon resonance absorption on a metal grating with a gold over-coating and the results are compared with experimental data. Enhancement of TM-TE mode conversion accompanying the plasmon resonance absorption is examined. When a TM wave is incident on a metal grating, enhanced TM-TE mode conversion occurs at angles of incidence at which the surface plasmons are excited. The strength of the mode conversion depends strongly on the azimuth angle of the mounting. This is verified by experiment and an application for refractive index measurement is suggested.

In this paper, circular and hexagonal array geometries for smart antenna applications are compared. Uniform circular (UCA) and hexagonal arrays (UHA) with 18 half-wave dipole elements are examined; also planar (2 concentric rings of radiators) uniform circular (PUCA) and hexagonal arrays (PUHA) are considered. The effect of rotating the outer ring of the PUCA is studied. In our analysis, the method of moments is used to compute the response of the uniform circular and hexagonal dipole arrays in a mutual coupling environment. The particle swarm optimization (PSO) algorithm is used to optimize the complex excitations, amplitudes and phases, of the adaptive arrays elements for beamforming.

A new method is introduced to analyze lossy Inhomogeneous Planar Layers (IPLs). In this method, the equations of IPLs are converted to the equations of homogeneous planar layers, which have been excited by distributed equivalent sources. Then, the electric and magnetic fields are obtained using an iterative approach. The validity of the method is verified using a comprehensive example.

A novel fast and accurate interpolation technique for recovering the uniformly distributed samples from the irregularly spaced samples, collected non-uniformly due to the probe position error in planar near-field antenna measurements, is presented. The technique employs Yen's interpolator and tries to make it as practical as possible for the use in near-field antenna measurements. A comprehensive simulation capability is developed and through out the simulations the speed and precision of this accurate and timely efficient interpolation technique is compared with some other techniques which are also based on Yen's interpolators. The results well demonstrate the advantages of our technique we termed "The Cross-Rail Technique".

A novel band-pass Substrate Integrated Waveguide (SIW) filter based on Complementary Split ring Resonators (CSRRs) is presented in this work. Three different CSRRs cells are etched in the top plane of the SIW for transmission zero control. A demonstration band-pass filter is designed, fabricated and measured. It agreed with the simulated results well.

A rigorous solution in L₂ to the EFIE for 2-D screens is developed and proposed as a reference solution for testing the convergence rate and scattering amplitude error of any MoM algorithm in L₂. The proposed reference solution permits to choose judiciously an appropriate mesh density for a MoM algorithm instead of using the ten-points-rule in all cases. Additionally, using the reference solution it is demonstrated that the discrepancy should not be used as a performance value of the scattering amplitude error while solving the EFIE with the MoM in L₂. Both the E- and H-cases are considered.

In this paper, the performance of the separated-aperture sensor working as ground-penetrating radar (GPR) is assessed over the operating frequency band. The capability of the separatedaperture sensor to detect buriedtargets is examinedb y evaluating andcomparing the electromagnetic coupling between the transmitting andreceiving antennas in two cases: (i) when the system is placed over an empty groundand(ii) when it is placedo ver a groundinsid e which a practical target is buriedat the proper depth. The finitedifference time-domain (FDTD) method is used for electromagnetic simulation. The results concerning the coupling between the transmitting andreceiving antennas are presentedconsid ering various practical parameters such as the operating frequency, the electric properties of the groundsoil andthe buriedtarget, andthe depth at which the target is buriedund er the groundsurface. It is shown that target detectability using the separated-aperture sensor is strongly dependent on all of the above parameters.

In this paper, a flat multilayer dielectric reflector antenna has been designed and analyzed. The reflector is made of several sandwiched dielectric layers. The structure is hence an array made of these layers, where the sum of the reflection coefficient of each layer acts as the array factor. By optimizing the permittivity and thickness of each layer, any desired reflection coefficient to shape the reflected pattern can be obtained. It is also possible to synthesize a zero or a maximum in any arbitrary direction. The significance of the reflector is ability to radiate high power and at the same time having small dimensions.

The quasi-linear Maxwell equations describing electromagnetic wave propagation in nonlinear media permit several weak solutions, which may be discontinuous (shock waves). It is often conjectured that the solutions are unique if they satisfy an additional entropy condition. The entropy condition states that the energy contained in the electromagnetic fields is irreversibly dissipated to other energy forms, which are not described by the Maxwell equations. We use the method employed by Krûzkov to scalar conservation laws to analyze the implications of this additional condition in the electromagnetic case, i.e., systems of equations in three dimensions. It is shown that if a cubic term can be ignored, the solutions are unique and depend continuously on given data.

A ring source of arbitrary current backed by a perfectly conducting sphere is analyzed through Green's function formulation. The infinite double sum of the Green's function is written in terms of a single series by performing a transformation of the coordinate system. The resulting form is used for the numerical evaluation of the scattering integral. The operation of the coupled loop-sphere structure is understood via the discussion of several numerical results.

Astudy is presented of the light wave propagation in a new type of dielectric optical waveguide with hyperbolic kind of crosssection. Further, the waveguide is assumed to have a conducting helical winding. The analysis essentially requires the use of elliptical coordinate system, which finally results into Mathieu and modified Mathieu functions as the representatives of the electromagnetic fields within the lightguide. Field components in the different sections of the guide are deduced, and the characteristic dispersion equation for the system is derived. The preliminary investigation on such type of waveguide throws the idea that the presence of helix pitch angle (which serves the purpose of additional controlling parameter for the guide) in the dispersion relation would greatly affect the propagation characteristics of the guide, and this can be of great practical importance.

An algorithm focusing on the occlusions between rays and NURBS surfaces is presented in this paper,where simple geometrical principle which makes the algorithm adequate in possible cases is used. When the ray starts from or ends on the surface,the self-shadowing is also taken into account. The algorithm given can be applied to optical methods like PO GTD or UTD in electromagnetic calculation where shadowing is of key problem and especially when the NURBS modeling is introduced.

High frequency field expressions are derived around feed point of a two dimensional cassegrain system using the Maslov's method. Maslov's method is a systematic procedure for predicting the field in the caustic region combining the simplicity of ray theory and generality of the transform method. Numerical computations are made for the analysis of field pattern around the caustic of a cassegrain system.

In this paper, wide band transmitting and receiving antennas; each composed of a bowtie partially covered by an open conducting box; are proposed for ground-penetrating-radar (GPR) system. The inner walls of the conducting box are covered by a lossy coating which is composed of a number of layers with a conductivity profile designed to achieve better characteristics of the bowtie antenna. The Finite-Difference Time-Domain (FDTD) method is applied to simulate the radiating and receiving antennas, the buried target and the wave propagation in the lossy ground soil over the frequency band of operation. The performance of the proposed system is examined as regards the antenna characteristics and the buried target detectability. The impedance and voltage standing wave ratio (VSWR) of the partially covered bowtie antenna are presented over a wide frequency range. The capability of the proposed GPR system to detect targets buried in a ground soil is examined by investigating the change of the coupling between the transmitting and receiving antennas due to the presence of a buried target. The effect of the ground soil on the antenna characteristics is studied for some common types of real soils when the GPR system is placed at different heights above the ground surface.

In this paper, the bistatic polarimetric signature of a perfectly conducting faceted octahedron with high dimensions with respect to the wavelength, is considered and a closed form solution for its fast computation is developed. This particular object, composed by eight triangularly shaped trihedral corner reflectors, should exhibit a large bistatic and monostatic Radar Cross Section (RCS) over a wide angular range. Scattering from a Trihedral Corner Reflector (TCR) is dominated by single, double and triple reflections. First, shadowed areas in excitation and observation are evaluated with the help of Geometrical Optics (GO). A Physical Optics (PO) integration is performed on each plate for the computation of scattered fields, taking into account the shadowed surfaces. GO is used to take into account the lighting of each face for initial reflections of double and triple reflections. First-order diffractions, which are based on the fringe current expressions for the exterior edges of the TCR are also included in the analysis with the help of Method of Equivalent Currents / Incremental Length Diffraction Coefficients (MEC/ILDC). This permit us to calculate fast the bistatic signature of a TCR for arbitrary incidence and observation angles. The polarimetric bistatic signature of an octahedral reflector is then obtained, and results are discussed. Finally, several prospects are explained

Abstract-In this paper, ray propagation in stratified semi-infinite percolation lattices consisting of a succession of uniform density layers is considered. Two different mathematical approaches for analytically evaluating the penetration depth are presented. In order to compare performances and to assess the range of validity of the two approaches, an exhaustive set of numerical Monte-Carlo-like experiments is presented.

In this paper, a miniaturized printed dipole antenna with the V-shaped ground is proposed for radio frequency identification (RFID) readers operating at the frequency of 2.45 GHz. The principles of the microstrip balun and the printed dipole are analyzed and design considerations are formulated. Through extending and shaping the ground to reduce the coupling between the balun and the dipole, the antenna's impedance bandwidth is broadened and the antenna's radiation pattern is improved. The 3D finite difference time domain (FDTD) Electromagnetic simulations are carried out to evaluate the antenna's performance. The effects of the extending angle and the position of the ground are investigated to obtain the optimized parameters. The antenna was fabricated and measured in a microwave anechoic chamber. The results show that the proposed antenna achieves a broader impedance bandwidth, a higher forward radiation gain and a stronger suppression to backward radiation compared with the one without such a ground.