30 research outputs found
Analysis of a nonconfocal suspended strip in an ellipticalcylindrical waveguide
The separation of variables method along with an addition theorem of Mathieu functions are employed in this paper to analyze the problem of a nonconfocal suspended strip in an elliptical waveguide. An infinite-dimensional determinant is obtained, which represents the characteristic equation of the proposed structure. To obtain the cutoff wavenumbers for both TE and TM cases of such a structure, the infinite determinant is truncated. Convergence when truncating was observed. Numerical results for the special case of a confocal structure is discussed first for comparison with published data. Results of other interesting cases are also presente
Radiation from an open ended eccentric annular waveguide
The radiation from an open ended eccentric annular waveguide is examined here. The region between the two circular conductors is assumed to have either symmetrical or anti-symmetrical TE field distribution. The cut-off wavenumber is first calculated and the unknown coefficients in the field are then obtained. It is found that for anti-symmetric field distribution the radiation pattern in the H-plane has a null which can be widely scanned by displacing the conducting core from the central axis. For the symmetrical field distribution a pair of symmetrical nulls in the E-plane are slightly scanned with the displacement of the conducting core. This type of waveguide antenna is useful for applications in phased and adaptive arrays which require null scannin
Scattering by a dielectric coated conducting cylinder loading asemicircular channel in a ground plane
The boundary value method is used to derive a dual series solution of a plane wave incident on a dielectric coated conducting circular cylinder imbedded in a semicircular channel in a ground plane. The partial orthogonality of the trigonometric functions is used to obtain the scattering coefficients. The resulting infinite series is then truncated to a finite number of terms to produce numerical results. Special cases are first introduced for comparison with the corresponding published results. The comparison shows an excellent agreement in all cases. More general examples are then introduce
Scattering by a dielectric coated conducting cylinder loading asemicircular channel in a ground plane
The boundary value method is used to derive a dual series solution of a plane wave incident on a dielectric coated conducting circular cylinder imbedded in a semicircular channel in a ground plane. The partial orthogonality of the trigonometric functions is used to obtain the scattering coefficients. The resulting infinite series is then truncated to a finite number of terms to produce numerical results. Special cases are first introduced for comparison with the corresponding published results. The comparison shows an excellent agreement in all cases. More general examples are then introduce
Electromagnetic scattering from a coaxial dielectric circularcylinder loading a semicircular gap in a ground plane
An exact dual series solution of a plane wave incident on a coaxial dielectric circular cylinder imbedded in a semicircular gap of a ground plane is presented. Both TM and TE cases are considered here. The scattered field is represented in terms of an infinite series of cylindrical waves with unknown coefficients. By applying the boundary conditions and employing the partial orthogonality of the trigonometric functions the scattering coefficients are obtained. The resulting infinite series is then truncated to a finite number of terms to produce numerical results. For the sake of comparison with the published data some special cases are introduced first. The comparisons showed excellent agreement in all case
Analysis of a nonconfocal suspended strip in an ellipticalcylindrical waveguide
The separation of variables method along with an addition theorem of Mathieu functions are employed in this paper to analyze the problem of a nonconfocal suspended strip in an elliptical waveguide. An infinite-dimensional determinant is obtained, which represents the characteristic equation of the proposed structure. To obtain the cutoff wavenumbers for both TE and TM cases of such a structure, the infinite determinant is truncated. Convergence when truncating was observed. Numerical results for the special case of a confocal structure is discussed first for comparison with published data. Results of other interesting cases are also presente
Electromagnetic scattering from a perfectly conducting stripembedded in a dielectric cylinder
Scattering from a perfectly conducting strip arbitrarily embedded inside a dielectric cylinder of circular or elliptical cross-section is investigated. Numerical results are obtained, and their accuracy is investigated for a variety of physical and electric parameters by comparing the scattered field pattern with numerical results obtained using other techniques. It is found that the numerical computations based on this analysis are rapidly convergent and few terms are needed to obtain reasonably accurate result
Radiation characteristics of an infinite dielectric-coated axiallyslotted cylindrical antenna partly embedded in a ground plane
The radiation characteristics of an axial slot on a dielectric-coated conducting circular cylinder embedded in a semi-circle in an infinite ground plane (GP) are examined. The boundary-value method is employed to obtain the solution with the aid of the partial orthogonality of the trigonometric functions. The resulting dual infinite series involved in the solution is then truncated to generate numerical results. The geometry considered here is important because it can be implemented on the body of any mobile communication system. Moreover the GP adds a new parameter to the slotted dielectric-coated conducting circular cylindrical antenna and can be used in beam shaping and to enhance the antenna performanc
Radiation characteristic of slots on conducting circular cylindercovered by eccentric dielectric cylinder
The radiation characteristics of axial slots on a circular conducting cylinder covered by an eccentric dielectric cylinder are investigated. A dual infinite-series solution based on the boundary-value method is obtained with the aid of the addition theorem of Bessel functions. The dual infinite series involved in the solution is then properly truncated to generate numerical results. Comparison with published data for concentric cylinders shows excellent agreement. Several interesting radiation characteristics corresponding to new geometries of the coated slot cylindrical antenna are presente
Radiation by an axial slot on a dielectric-coated concentricconducting circular cylinder loading a semicircular gap in a groundplane
The radiation characteristics of an axial slot on a dielectric coated conducting circular cylinder imbedded in a ground plane is examined. The boundary value method is employed to obtain the solution with the aid of the partial orthogonality of the trigonometric functions. The resulting dual infinite series involved in the solution is then truncated to generate numerical results. The geometry considered is important because it can be implemented on the body of any mobile communication syste