Homogeneous microwave near-field power focusing using a cylindrical antenna array.

This paper presents an investigation of a microwave near-field power focusing (NFPF) analytical approach utilizing a cylindrical array of electric line sources along the z-axis, applicable to any arbitrary homogeneous linear medium. A novel parameter, termed the "focus ability" (FA), is introduced to quantitatively assess a method's capabilities in achieving power focusing. In the following, the phases and amplitudes of the excitation signals of the array elements are obtained with optimization to maximize FA over a certain studied area.

Synthesis of unequally-spaced arrays using the fractional Fourier series.

This paper introduces an algebraic method to synthesize the radiation pattern of unequally-spaced arrays. In this method, first, the characteristic matrix, containing the sampled data of the desired pattern, is established. Then, the fractional Fourier series is calculated using the distinct eigenvalues and eigenvectors of the characteristic matrix.

Planar metal-only omnidirectional retroreflector using transmitarray and blazed grating for TE and TM polarizations.

Retroreflector is a device that reflects light along its incident direction over a continuous range of incident angles. The retroreflectors proposed so far are so bulky and uneven that they cannot be mounted on large structures. Recently, two-layer planar retroreflectors have been proposed in the field of optics and acoustics, but at microwave frequencies only one retroreflector with non-planar overall structure has been presented that doesn't cover omnidirectional incidence and only supports TM polarization.

Planar, wide-band omnidirectional retroreflector using metal-only transmitarray structure for TE and TM polarizations.

In this paper, a novel planar and wideband metal-only retroreflector is proposed that efficiently reflects the obliquely incident electromagnetic wave along its incident direction in omnidirectional angle range. The means of omnidirectional is the capability of retroreflectivity in all azimuth angles [Formula: see text] and in a wide elevation angle [Formula: see text] range. The proposed structure consists of a symmetrical transmitarray structure with beam scanning capability in which a metal plate is placed instead of the feed.

Pattern synthesis of linear and ring arrays with minimum number of elements using FFT and Bessel transformation.

In antenna engineering, to reduce the final cost of array design, it is often necessary to design an array with the minimum number of elements. So, proper selection of the number of array elements and the location of the elements are two important factors in array design. In this work, a novel analytical approach for designing an array with optimal parameters is described.

Synthesis of low sidelobe level antenna arrays through only main lobe assumption.

An analytic method is proposed to design uniformly spaced arrays so that have as low as possible sidelobe level and having directivity as close as to that of uniformly excited arrays. The ideal array factor of arrays is assumed to have only one main lobe. The actual synthesized array would have sidelobe levels which can be controlled by a parameter.

Matched and wideband flat lens antennas using symmetric graded dielectrics.

Matched and wideband flat lens antennas using a two-dimensional symmetric graded dielectric (SGD) are considered. An explicit relation for refractive index of this type of antenna is presented. This design relation is obtained in two steps.

Design of a broadband hemispherical wave collimator lens using the ray inserting method.

This paper presents a novel inhomogeneous hemispherical dielectric lens. The proposed lens is designed based on the ray inserting method (RIM). Applying this approach, a uniform distribution of the rays' end points over the lens plane aperture is achieved while lens matching to the environment refractive index is perfectly fulfilled.

Effect of optical transformation order on design of arbitrary polygonal invisible cloak.

The design of an arbitrary polygonal invisible cloak is introduced in this paper by considering the different transformation orders. The transformation order is considered as a design variable to achieve the allowable constitutive parameters for a practical cloak with the optimum performance. In the proposed method, a thin layer is removed from the inner cloak boundary to avoid the inevitable singularity at this boundary.

Arbitrary n-sided irregular polygonal electromagnetic transformed media.

The design of an arbitrary n-sided irregular polygonal transformed media is introduced in this paper. The generalized proposed optical transformation is based on a very simple Y-intercept transformation in the Cartesian coordinate system. In this method, the arbitrary shaped transformed media is decomposed into triangular segments.