A 3-5 GHz broadband CMOS single-ended LNA with a new theoretical approach based on least-square algorithm is presented in this paper. The design consists of a wideband input impedance matching network, a cascoded amplifier with inductively-degenerated LNA, and an output impedance matching network. It is simulated in TSMC 0.18 μm standard RF CMOS process. The optimum matching network is designed to minimize the noise figure (NF) and maximize the power gain. The element values of optimum matching network have been obtained using the least-square algorithm. The proposed LNA exhibits a gain in range of 19.9-18.9 dB, over the UWB low-band (3 to 5 GHz). Moreover, the noise figure is obtained in range of 0.6-0.8 dB. Besides, the input P1-dB and IIP3 are -10.5 dBm and 18 dBm, respectively. The proposed method has minimum 4 dB power gain improvement in relative to similar works with constant noise figure. Also, the DC supply is considered to be 1.8 V.

The Fourier series expansion method is a useful tool to approach the problems of discontinuities in optical waveguides, and it applies to analyze the Floquet-modes of photonic crystal waveguides. This paper shows that the Floquet-mode calculation with large truncation order is limited and explains the reason. Furthermore, two techniques of the formulation are presented to relieve this limitation. One of them is a use of the symmetric properties of the Floquet-modes, and another is a use of the Rayleigh quotients to improve accuracy of eigenvalue calculation. They are validated by numerical experiments.

This paper proposes a novel subspace projection algorithm for impulsive interference (IMI) suppression in echo samples received by an over-the-horizon radar (OTHR). We particularly highlight the model that the frequency spectrum of IMI component is a complex cosine signal such that IMI cosine can be filtered out by subspace projection. Compared with existing algorithms, a more simple clutter suppression algorithm is used to reject the most powerful clutter components. Furthermore, this algorithm will neither estimate nor need the exact temporal position of IMI, which avoids the impact resulted from the position estimation error. Another advantage is its little impact on true target signal and no impact on the clutter. Experimental results based on data from real high frequency surface wave (HFSW) OTHR systems are also shown to verify the proposed algorithm.

In the wireless communication systems, the objective of using array antennas is to extract the desired signal while filtering out the unwanted interferences. New methods are developed for the optimization and synthesis, in terms of the directivity and the side lobe level. For the optimization of the array pattern, it is proposed to adjust both the excitation and the spacing of the antenna elements. The determination of the optimal excitation and spacing is shown to be a polynomial problem; this is described in terms of a unified mathematical approach to nonlinear optimization of multidimensional array geometries. The approach utilizes a class of limiting properties of Legendre functions that are dictated by the array geometry addressed. The objective of this paper is to describe a unified mathematical approach to nonlinear optimization of multidimensional array geometries.

A single-feed low-profile and easy to fabricate circularly polarized microstrip patch antenna has been developed for GPS applications. For dual frequency operation, four slots are etched near edges of the patch and a crossed slot etched in the center for generating circular polarization. In order to reducing the frequency ratio of two frequency bands of the antenna, the patch is loaded by four short circuit microstrip stubs. The paper reports several simulation results that confirm the desired characteristics of the antenna. Using stub loading, the frequency ratio of two bands of the antenna can be, even, reduced to 1.1.

In this paper, a calculation method for bore sight error voltages is presented for aperture antennas enclosed in radomes of arbitrary shapes. The method adopts a ray tracing technique frequently used in computer graphics field in constructing two dimensional computer graphics images to obtain a projected image of source distribution, thereby bore sight error voltages and far field radiation patterns are calculated fast and accurately. Besides, the method enables us to use various acceleration schemes used in computer graphics readily. Numerical calculations show that projected source images with a resolution higher than 0.1λ and multiple reflections taken into account produce reliable results. The validity of the method is verified by comparison with results of an analytic solution.

This letter presents a compact low temperature co-fired ceramic (LTCC) receiver front-end module integrating 9 building blocks. The receiver is a twicefrequency- conversion front-end module with image injection, works at X-band, consists of an X-band embedded image injection band-pass filter (BPF), an L-band multilayer image injection quasi-ellipitc BPF, two monolithic microwave integrated circuit (MMIC) low noise amplifiers (LNAs), two intermediate frequency (IF) amplifiers, two mixers, a IF BPF, and some lumped passive components. All MMICs are mounted into pre-making cavities in the three layers LTCC substrate of the top surface, and the interconnection between MMICs and surface microstrip-line is established by bond wires. A multilayer five-pole Chebyshev interdigital BPF is developed as the first image injection filter, and a four-pole quasi-elliptic BPF composed of stepped-impedance hairpin resonator and miniaturized hairpin resonators that can be coupled through the apertures on the common ground plane is proposed for as the second image injection filter. The developed X-band receiver front-end module is fabricated using twenty layers LTCC dielectric substrate, which has a compact size of 30 × 20 × 20 mm³ (including the metal cavity). The measured receiver gain and noise figure are more than 32 dB and less than 4 dB, respectively. The first and second image injection is better than 28 dB and 40 dB, respectively.

In this paper, theoretical and simulation studies on rectangular and annular dielectric resonator antenna (DRA) made of TiO₂ was reported. The ceramic was fabricated by solid state reaction at 1200^oC. The structural and dielectric properties were investigated by X-Ray Diffraction (XRD), Field Emission Electron Microscopy (FESEM) and network Analyzer. The XRD results showed the presence of rutile phase and the microstructure comprised of fine grain (0.2-0.5 μm) and large grain 1.0-1.5 μm. The rectangular and annular shape TiO₂ DRA with high dielectric constant (ε=84) and low loss tangent (0.080) were fed with 50Ω microstrip transmission line and comparision between the various shape were investigated. The return loss, input impedance and radiation pattern TiO₂ DRA was studied. Design simulation results using CST Microwave Studio 2008 also was presented.

In this paper, the cosinusoidal slot aperture distribution is replaced with a two term approximation. Using this two term approximation, the slot fields are evaluated in closed form and explicit expressions are given in terms of sine and cosine integrals. The two term approximation and the near fields derived therefrom agree closely with the cosinusoidal distribution for slot lengths upto 0.65λ, with an error of less than 3.3% with respect to the numerical results upto 0.05λ from the slot in the near field. The formulation given here is of practical use in estimating mutual coupling in an array or in estimating radiated emissions for Electromagnetic Compatibility (EMC) analysis.

This paper presents a class of ultra-thin metamaterial absorbers, which consists of periodic microstrip lines on top of a planar lossy substrate backed by a conducting metallic plate. A highly efficient full-wave analysis method was developed to solve the electromagnetic response of the absorbers. The in uence of electromagnetic properties of the substrate and physical dimensions of the microstrip lines were analyzed. Genetic algorithm was used to optimize the absorption bandwidth of the absorbers. Effective permeability and permittivity of the absorbers were retrieved to shed a new light on the absorption mechanism of the absorbers and to explain their ultimate bandwidth limit. It was found that the ultimate bandwidth limit of the metamaterial absorbers is the same as that of normal absorbers.

The present paper sets out to present a numerical electromagnetic (EM) method TWA for EM field modeling of planar structures. Combining both the benefits of TWA process and the modeling of planar excitation source, an optimization technique AMT is applied and evaluated in context of RF integratedcircuit applications. The computational complexity of TWA process is examined and the obtained simulation results are found to be in good agreement with literature.

The geometrical parameters of antenna arrays in a multiple-input multiple-output (MIMO) link that will maximise the ergodic channel capacity of the system are investigated. The problem of selecting the optimum number of the elements at the base station antenna array is also included. The genetic algorithm technique is applied for the optimisation process, using the ergodic capacity as a fitness function. A discrete model based on statistical distribution of the Angle of Arrival (AoA) of the incoming rays is considered. Searching for more compactness in the antenna size and higher system capacity, different array configurations with non-uniform inter-element spacing are considered, such as linear array, circular array and multi-circular array (Star) geometries. Numerical examples that illustrate new designs of non-uniform spaced arrays are presented to show the capability of the developed procedures to optimize the capacity of indoor MIMO systems.

A deterministic method for detecting faulty elements in phased arrays is proposed and tested against experimental and numerical data. The solution approach assumes as input the amplitude and phase of the near-field distributions and allows to determine both positions and currents of radiating elements. The corresponding non linear inverse problem is properly solved by exploiting the distributional approach, which allows to cast the initial problem to the solution of a linear one, whose solution is made stable by adopting a proper regularization scheme based on the Truncated Singular Value Decomposition tool. The results fully confirm accuracy of the proposed technique.

In this article, designs and analyses of several CCPW (Cylindrical CPW) discontinuities have been realized as microwave reactive elements. The quasi-TEM characteristic parameters of CCPWs have been obtained by CMT (Conformal Mapping Techniques) which provide satisfactory accuracy at microwave frequencies and lead to closed-form analytical solutions suitable for CAD software packages. Then these discontinuities have been simulated in CST Microwave Studio 2006 in order to obtain inductance, capacitance and also input impedance versus frequency and physical dimensions of the elements. The results show that CCPW discontinuities can be used successfully as reactive elements for related applications.

In this paper we investigate boundary effects and other consequences of spatial dispersion by analyzing in detail the response of a metamaterial half-space to a monochromatic plane wave normally incident from free-space. The metamaterial is composed of an orthorhombic lattice of identical particles, each of which exhibits both an electric and magnetic response. Rather than relying on the conventional boundary conditions and the Clausius-Mossotti equations, we use instead the point-dipole interaction model and an expansion of polarization in eigenmodes to determine the structure's dispersion relation and electromagnetic response. Using the nearestneighbor approximation, we show how truncating the crystal lattice excites an "ordinary" mode and two "extraordinary" modes that are necessary to satisfy the boundary conditions at the interface. For most cases, the extraordinary modes are evanescent, and thus form a thin transition layer at the surface. However, under certain conditions, typically near particle resonances, either one or both of these modes can be propagating.

We present the theoretical development of the 3D multipole probability tomography applied to the electric Self-Potential (SP) method of geophysical exploration. We assume that an SP dataset can be thought of as the response of an aggregation of poles, dipoles, quadrupoles and octopoles. These physical sources are used to reconstruct, without a priori assumptions, the most probable position and shape of the true SP buried sources, by determining the location of their centres and critical points of their boundaries, as corners, wedges and vertices. At first, a few synthetic cases with cubic bodies are examined in order to determine the resolution power of the new technique. Then, an experimental SP dataset collected in the Mt. Somma-Vesuvius volcanic district (Naples, Italy) is elaborated in order to define location and shape of the sources of two SP anomalies of opposite sign detected in the northwestern sector of the surveyed area. The modelled sources are interpreted as the polarization state induced by an intense hydrothermal convective flow mechanism within the volcanic apparatus, from the free surface down to about 3 km of depth b.s.l..

This paper presents the graphical solutions of conjugately characteristic-impedance transmission lines (CCITLs) implemented by periodically loaded lossless transmission lines (TLs), which can exhibit both non-negative (NNCR) and negative characteristic resistances (NCR) with the corresponding propagation constants. The standard T-chart and the extended T-chart are employed to solve CCITL problems with NNCR and NCR cases respectively, depending on the argument of CCITL characteristic impedances. The range of plotting of the standard T-chart and the extended T-chart is always inside or on the unit circle, and always outside or on the unit circle of the voltage reflection coefficient plane, respectively. Two examples of finite periodic TL structures providing both NNCR and NCR cases are given. It is found that both T-charts provide the same input impedance of the corresponding CCITLs as expected, and the standard T-chart is more familiar and easier to deal with.

A circulator with a coplanar structure is designed and analysed using a three dimensional finite element method. Based on the proposed design, the circulator is fabricated with a YIG (Yttrium Iron Garnet). The thickness of YIG is only 65 μm. The design is planar and realized by stacking several layers, resulting in a potentially simple and low cost industrial process. Simulated results are better than measured ones but circulation is obtained around 9 GHz. Measured insertion loss is 5 dB and isolation is 36 dB giving interesting perspectives for the device.

A novel wire antenna configuration is proposed to achieve a 90 degree azimuthal beamwidth in the VHF band. The antenna has been manufactured and the measurement results are presented.

A directly modulated fiber-to-the-home (FTTH)/radio-over-fiber (ROF) transport system based on -1 side mode injection-locked and optoelectronic feedback techniques is proposed and demonstrated. Directly modulated baseband (BB) (622 Mbps) and radio frequency (RF) (622 Mbps/10 GHz) signals are successfully transmitted simultaneously over an-80 km standard single-mode fiber (SMF) transmission. Low bit error rate (BER) values and clear eye diagrams were achieved in our proposed systems. This demonstrated FTTH/ROF transport system is a promising candidate for broadband access networks.