In this work, Support Vector Machine (SVM) formulation is worked out based upon ''L'' measured data for the resonant frequency, operation bandwidth, input impedance of a rectangular microstrip antenna. Results of the formulation are compared with the theoretical results obtained in literature, much better characterization is observed with greater accuracy. At the same time, Artificial Neural Network (ANN) is employed in generalization of the data on the resonant frequency, operation bandwidth, and input impedance of the antenna. Performances of the two advanced nonlinear learning machines are compared and superiority of the SVM is verified.

A new uniplanar electromagnetic bandgap (EBG) power/ground planes is proposed with broadband suppression of simultaneously switching noise (SSN) from 370MHz to 4.9 GHz. Meander line bridge is used to increase the inductance between the two neighboring units, which can make the proposed power/ground structure suppress the SSN at low frequencies effectively. Excellent SSN suppression performance is validated both numerically and experimentally. Good agreement is seen. The proposed uniplanar EBG power/ground planes structure can be widely used in high speed integrated circuits.

Research of antenna Radar Cross Section (RCS) is very important for low observable platform. Aperture coupled microstrip antenna is fit for the low RCS antenna design because the feed network produce less effect on scattering of microstrip patch. A novel aperture coupled microstrip antenna is proposed, which utilizes the chip-resistor load, ground slot and miniaturization, to realize RCS reduction. Aperture coupled antenna with rectangular patch is chosen as the reference antenna. Two antennas are simulated and measured. The measured results show that the designed antenna realizes only 0.5 dB gain loss while RCS are reduced in almost all the frequency band.

A thin internal planar antenna for GSM/DCS with a hollow shorting cylinder suitable for integration with an embedded digital camera for a mobile phone is presented. A small vertical ground plane electrically connected to the system ground plane of the mobile phone is used. The vertical ground plane can function as an effective shield wall between the antenna and the nearby electronic elements in the mobile phone. The method of moments is used to simulate the antenna structure and calculate the radiation characteristics of the antenna.

This paper proposes an improved adaptive approach involving Bacterial Foraging Algorithm (BFA) to optimize both the amplitude and phase of the weights of a linear array of antennas for maximum array factor at any desired direction and nulls in specific directions. The Bacteria Foraging Algorithm is made adaptive using principle of adaptive delta modulation. To show the improvement in making the algorithm adaptive, results for both adaptive and nonadaptive algorithms are given. It is found that Adaptive Bacteria Foraging Algorithm (ABFA) is capable of improving the speed of convergence as well as the precision in the desired result.

Magic tee is a widely used component in microwave systems; the four arms of a conventional magic tee direct at four different directions, which occupy much space and give inconveniences to the assemblage of a system. In this paper, a waveguide narrow-wall slot directional coupler and an E-plane dielectric loaded waveguide phase shifter are used to make up of a magic tee with four arms in the same H-plane. The narrow-wall slot directional coupler is analyzed with mode matching method and optimized with simulated annealing method, and the dielectric loaded waveguide phase shifter is designed with edge based finite element method. Numerical results of the magic tee are presented, which show that the performance of the designed magic tee is good.

This paper reports the miniaturization of a microstrip 90 degree coupler by substituting the quarter wave transmission lines employed in conventional 90 degree coupler with its equal circuits consisting of two oblique stubs and an inductor and capacitors. Reduction of the coupler to 27% its size is reported here. This coupler is designed at 1070MHz for using in even harmonic mixers of 3G mobile receivers. Furthermore, the coupler can accurately divide the input signal by two parts with the same power and 90 degree phase difference. Also, the reflection coefficient and the isolation are as good as conventional one and coupling procedure is better than it.

Finite-Difference Time Domain (FDTD) is used to calculate the input impedance of the cylindrical dielectric resonator (DRA) antenna with different dimensions. A lumped- element circuit model for the input impedance calculation is proposed. The genetic algorithm is used to calculate the elements of the equivalent circuit. The Model-Based Parameter Estimation (MBPE) technique is used to find the variation of each element in the equivalent circuit with varying the physical dimensions of the antenna. The use of this method reduces the time required for calculating the input impedance of the cylindrical DRA in eachv ariation of the antenna dimension.

This paper reports a high IIP3 even harmonic mixer with a new circuit configuration. This mixer employs an antiparallel diode pair, open and short circuited stubs and a radial stub as filters to separate RF input signal, Baseband output signal and LO Power. This mixer is used for down converting 3G Mobile downlink Signal at 2140MHz to BaseBand by using a local oscillator at 1070MHz in direct conversion configuration. This mixer must comply with the requirements specified by 3G UMTS: 3rd order Input Intercept Point = 14.466dBm ≥ 11 dBm, Noise Figure = 9 dB and Conversion Loss = 11 dB.

We consider the inverse problem of determining both the shape and the conductivity of an un-uniform conductivity scatterer buriedin a three-layer structure by the genetic algorithm. An ununiform conductivity scatterer of unknown shape and conductivity buriedin the secondla yer scatters the incident wave from the first layer or the thirdla yer. We measure the scatteredfieldin the first andthird layers. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations is derived and the imaging problem is reformulatedin to an optimization problem. The genetic algorithm is then employedto findout the global extreme solution of the object function. As a result, the shape andthe conductivity of the scatterer can be obtained. Numerical results are given to demonstrate that even in the presence of noise, good reconstruction has been obtained.

We use coordinate transformation theory to realize substrates that can modify the emission of an embedded source. Simulation results show that with proper transformation functions the energy radiated by a source embedded in these space variant media will be concentrated in a narrow beam. The thickness of the slab achieved with our transformations will no longer be restricted by the evanescent modes and the source can be placed at any position along the boundary of the substrate without affecting the radiation pattern. We also discuss the case where reduced parameters are used,whic h still performs well and is physically realizable.

From the analytical theory of rough surface Green's function based on the extension of the diagram method of Bass, Fuks and Itô, with the smoothing approximation, numerical results are presented for Gaussian and sea spectra and compared with a benchmark method by considering a one-dimensional perfectly conducting Gaussian rough surface. The effects of multiple scattering due to the surface roughness are incorporated systematically into the solutions through an effective surface impedance, which can be iterated up to the second-order. In addition, comparisons of the bistatic scattering coefficients are presented with the first- and second- orders conventional small perturbation method. This study will be useful for remote sensing of the ocean surface, especially when the transmitter is close to the surface.

A time reversal method is studied and adapted to through-the-wall detection and localization of moving targets. Tests are realised on experimental data in a synthetic aperture radar configuration. The efficiency of the method to extract a moving target from a cluttered environment is proved on experimental data.

This paper presents a very small size microstrip antenna suitable for WLAN application. The main patch antenna consists of an M-shaped slot with shorting wall. With a shorted triangular parasitic patch and a folded patch overall antenna size is reduced. The simulated and measured results show that by selecting a proper shorting wall width, the proposed antenna can provide an impedance bandwidth of 21.17% covering the 4.93-6.09 GHz band. The antenna size is of order 0.1094λo × 0.1094λo × 0.0544λo (6 × 6 × 3mm3). The proposed antenna has 75% surface size reduction compared to a conventional patch antenna operating at the same centre frequency. The E- and H-plane radiation pattern across the entire operating bandwidth is provided.

A new mathematical method and proposal for generation of shape invariant potentials using supersymmetric quantum mechanics is introduced. For this purpose the potential term in the Schrodinger equation is expressed in terms of the super potential. The obtained equation transformed into well known ordinary second order differential equation. Using standard technique, the Nikiforov-Uvarov (NU) method the superpotential in the Schrodinger equation is expressed in terms of the parameters appeared in the NU-approach concluding to a nonlinear differential equation. By solving the obtained equation and using relation between superpotential and potential the shape invariant potentials are obtained. The proposed method is general and straightforward for introducing of the shape invariant potentials.

In this paper, the problem of electromagnetic scattering from resistive strips is solved and discussed. This problem is modeled by the integral equations of the second kind. The basic mathematical concept is collocation method using block-pulse orthogonal basis functions. An effective numerical method for solving these integral equations is proposed. The problem of electromagnetic scattering from resistive strips is treated in detail, the illustrative computations are given for several cases, and an extensive discussion on the obtained results is performed. This method can be generalized to apply to objects of arbitrary geometry.

In this paper, full-wave analysis of a microstrip-ring resonator capacitively coupled to Microstrip transmission line is presented. The method of the analysis is based on spectral domain in rectangular coordinate system. Since this coordinate system is not compatible with ring structure, triangular basis functions have been utilized for the current distributions on the ring surface. Applying Galerkin's method in spectral domain, the resonant frequencies of the structure and current distributions on the conductors are calculated and the effects of various parameters are studied. To verify the method of analysis, our results are compared with others and the accuracy of the method has been confirmed.

Diffraction of a plane wave from a geometry which contains an infinite slit in a perfect electric conducting (PEC) plane and a perfectly electromagnetic conductor (PEMC) cylinder is presented. The method is based on the extension of Clemmow, Karp and Russek solution for the diffraction by a wide slit. The results are compared with the published work and agreement is fairly good.

This paper presents a new frequency-sweep approach for the efficient calculation of S-parameters of planar microwave structures. The approach is based on approximating the frequency dependence of the real and imaginary parts of the S-parameters using neural networks. Due to its superior performance, radial basis functions neural network (RBF-NN) is adopted. A limited number of frequency samples are used to train the RBF-NN. Then, the trained RBF-NN is capable of providing a smooth frequency response with very high accuracy in a fraction of a second. The proposed method is applied to a number of planar microwave structures such as: Patch antenna with an inset feed, band-rejection filter, and branch-line coupler. According to the presented results, a speed factor of at least 10 is measured, and a maximum percentage error of 3.29% is recorded.

This paper considers the influence of interchannel crosstalk on pulse timing shift and optical power due to the propagation of optical pulse through a nonlinear dispersive fiber. The numerical results are shown. An influencing parameter of the pulse distortion through the fiber is the eye opening penalty.