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In this paper an improved particle swarm optimization algorithm (IPSO) for electromagnetic applications is proposed. In order to overcome the drawbacks of standard PSO, some improved mechanisms for velocity updating, the exceeding boundary control, global best perturbation and the simplified quadratic interpolation (SQI) operator are adopted. To show the effectiveness of the proposed algorithm, a selected set of numerical examples, concerned with linear as well as planar array, is presented. Simulation results show that the refined pinpointing search ability and the global search ability of the proposed algorithm are significantly improved when compared to the particle swarm optimization (PSO) and Genetic Algorithm (GA).

In this paper, a set of formulas to analyze the scattering from open-ended rectangular cavity is presented on the basis of Shooting and Bouncing Ray (SBR) method. By analyzing the ray paths inside the cavity, the Physical-Optics (PO) integration on the aperture is carried out in a close form. Using closed-form solution, the Radar Cross Section (RCS) of cavity in high frequency can be studied sententiously and accurately. All the peaks and nulls in the RCS plot of cavity are predicted successfully with the formulas deduced in the paper, and a 3-D scattering pattern of rectangular cavity is simulated by the proposed method.

In this paper, the edge-facet model is transformed to the Non-Uniform Rational B-Spline (NURBS) model. The parameters of the knot vectors and the control points of NURBS are computed based on the data points on the surface of a target, and the NURBS model is constructed with the parameters. The degrees of the two parametric directions of a NURBS surface and the B-spline basis function are also analyzed. The relative errors between the NURBS models and the real models prove that the modeling method proposed in this paper is exact. Finally, the results of the Radar Cross Section (RCS) computed by the Physical Optics (PO) method with NURBS models are illustrated, and the results prove that the modeling method is of high precision and can be widely used in computational electromagnetics techniques.

Impedance-Matching technique is in common use for antennas to broaden their bandwidth. Its application in hightemperature superconducting microstrip antennas is studied theoretically in this paper. It is found that employing an impedance-matching network directly to HTS microstrip antennas to broaden their bandwidth is of little significance.

A method is presented to calculate the monostatic Radar Cross Section (RCS) of an electrically large perfect conducting cylinder vertically located over a dielectric half-space using Physical Optics (PO) technique. The four-path modal method is used to approximate the influence of the half-space to the scattering mechanism. The comparison between the results calculated by this expression and that by Moment Method (MOM) show that the expression is effective and efficient.

The variational closed-forms of the capacitance formulae of a type of conformal coaxial lines are presented in this paper with the assumption that the equipotential lines are conformal to the contour of the coaxial line. The variational extreme formula of the functional of continuous functions is first obtained. Then the variational stable and analytical expression of the capacitance is deduced. Considering the actual applications, we give the variational stable formulae of the capacitances of the conformal coaxial transmission lines whose contours are homogeneous curves of the 1st, 2nd and n-th order. Examples are given including the conformal regular polygonal, elliptical and high- order elliptical coaxial lines.