Browsing by Subject "Complex source"

Now showing 1 - 4 of 4

Open Access
Analysis of an arbitrary conic section profile cylindrical reflector antenna, H-polarization case
(IEEE (Institute of Electrical and Electronics Engineers), 2004) Oğuzer, T.; Nosich, A. I.; Altintas, A.
Two-dimensional scattering of waves by a perfectly electric conducting reflector having arbitrary smooth profile is studied in the H-polarization case. This is done by reducing the mixed-potential integral equation to the dual-series equations and carrying out analytical regularization. To simulate a realistic primary feed, directive incident field is taken as a complex source point beam. The proposed algorithm shows convergence and efficiency. The far field characteristics are presented for the reflectors shaped as quite large-size curved strips of elliptic, parabolic, and hyperbolic profiles.
Open Access
Complex source radiation in a cylindrical radome of metal-dielectric grating
(IEEE, 1999) Altintas, A.; Ouardani, S.; Yurchenko, V. B.
The radiation fields of a line source enclosed in a circular dielectric radorne with grating consisting of an array of thin lossy metal strips are analyzed. The variations of the directivity of the source beam with respect to the beam direction are studied. The possibility of damping these variations by an appropriate design of the radome is demonstrated.
Open Access
Effect of imperfect flat earth on the vertically polarized radiation of a cylindrical reflector antenna
(IEEE, 2000-02) Boriskina, S.; Nosich, A. I.; Altintas, A.
The radiation of a circular cylindrical reflector antenna in the presence of imperfect flat earth is treated in an accurate manner. The boundary value problem is formulated in terms of a full-wave integral equation converted to the dual-series equations and then regularized by using analytical inversion of the static part. The resulting Fredholm second-kind matrix equation is solved numerically with guaranteed accuracy. The feed directivity is included in the analysis by using the complex source-point method. Various antenna features, which include the overall directivity, efficiency, gain, and radiated and absorbed power fractions have been calculated and compared with the free-space antenna characteristics. They show some phenomena not predicted by approximate techniques.
Open Access
Radiation fields of the line source in a cylindrical wire grating
(1998) Karapınar, Hakan
In this thesis, the transmission effect of a grid structure is analyzed. The grid structure is intended to model the metallic support elements of a radome. The total field for the real and complex position line sources surrounded by the grating structure is obtained in both TM and 7'E polarizations in the far-field region. The grid is considered to be a cylindrical array of perfectly conducting cylinders parallel to the z-axis. The radius of each cylinder is small as compared to the wavelength and the length of the cylinders is infinite. We started with the study of a single perfectly conducting cylinder illuminated by a line source and obtained the formula for the electric and magnetic fields in the far-field region. Then, we calculated far-zone total field for a set of cylinders which form the surface of the radome as a cylindrical periodic grating. The equation for the total electric field in the far-field region is found by using superposition and applying the boundary conditions at the conducting cylinders to find scattering coefficients. Complex line sources are considered to simulate directed beam fields used in practice. The power pattern and directivity are computed for different parameters of the grating and cylinders. A set of figures is presented to show the relationships between the power pattern, directivity and different parameters of the structure.