Abstract-In this paper six novel Dielectric Resonator Antennas (DRAs) providing Circular Polarization (CP) using single probe feeds are proposed.By splitting the fundamental mode of conventional rectangular or cylindrical DRA into two near-degenerate orthogonal resonant modes, CP is obtained. The proposed antennas are numerically investigated using Finite Element Method (FEM). Parametric study on all antennas is carried out. The results show that the impedance bandwidth (S 11 < −10 dB) of all reported antennas is in the range of 112-140 MHz. Also, the Axial Ratio bandwidth (AR < 3 dB) range of presented antennas is 28-33 MHz. The investigation shows radiation patterns of all proposed antennas are remaining broadside throughout the bandwidth.

Abstract-The accurate analysis of scattering from objects with dimensions large compared to the wavelength using rigorous methods (finite element, FDTD, method of moments) with a personal computer is almost impractical. In asymptotic methods, physical optics (PO), geometrical theory of diffraction (GTD), the accurate modeling of the object's boundary is too cumbersome. The parabolic equation method gives accurate results in calculation of scattering from objects with dimensions ranging from one to tens of wavelengths. Solving parabolic equation with the marching method needs limited computer storage even for scattering calculations of large targets. In this paper, first the calculation procedure of radar cross section using parabolic equation in three dimension is studied and the necessary equations are derived. In order to show the validity of the parabolic equation, the RCS of a conducting sphere is calculated and the results are compared with analytic results. The airplane RCS has been computed by using a staircase model in the parabolic equation and the results are compared with physical optics results.