An effective, probe-compensated, phaseless Near-Field-Far-Field (NF–FF) transformation technique with planar spiral scanning is presented. The phase retrieval problem solved by a quadratic inverse process, whose data are the voltage squared amplitudes of NF samples acquired on two surfaces. available information antenna under test and geometry used to provide efficient representations for both ...

For an electromagnetic plane wave that is normally incident upon aperture or array in infinite perfectly electrical conducting plane, the validity of general expression for transmission cross-section as a measure transmitted power through investigated following two cases: first, single resonant (TRA) such complementary split ring resonator, which larger than Bethe’s small magnetic dipole; secon...

In modern rare isotope facilities, ion cooling and bunching lies at the heart of transfer along a low-energy beam line that consists several differential pumping stages. We present conceptual design an guide as alternative to conventional linear Radio-Frequency Quadrupole (RFQ) for isotopes. The is composed stacked ring electrodes varying apertures, which confining RF potential following rectan...

A method is described for designing high-efficiency rectangular horns that results in more compact horns than those obtained by using conventional linear tapers or steps. Results are presented for horns suitable for array feed or directly radiating array applications that show an aperture efficiency greater than 90% can be achieved over a 5% bandwidth with horns of aperture size ranging from 1....

Two new focus measure operators for Shape From Focus to estimate the three-dimensional shape of a surface are proposed in this paper. The images are formed by a camera using moving apertures. The well-focused image pixels are identified by frequency analysis or matching with the all-focused image of the scene. Frequency analysis involves the usage of classical focus measure operators and summin...

A method is developed theoretically that will permit subwavelength measurements of objects that differ from the surroundings by any contrast enhancing parameter, such as fluorescence, second harmonic generation, reflection et cetera, using a statistical analysis of a picture obtained with a conventional light microscope through a set of subwavelength apertures or by repeated scanning of a laser...

Zernike polynomials are commonly used to represent the wavefront phase on circular optical apertures, since they form a complete and orthonormal basis on the unit circle. Here, we present a generalization of this Zernike basis for a variety of important optical apertures. On the contrary to ad hoc solutions, most of them based on the Gram-Schmidt orthonormalization method, here we apply the dif...

We examine the threshold characteristics of selectively oxidized VCSELs as a function of the number, thickness, and placement of the buried oxide apertures. The threshold current density for small area VCSELs is shown to increase with the number of oxide apertures in the cavity due to increased optical loss, while the threshold current density for broad area VCSELs decreases with increasing num...

We show how the intrinsically performed JPEG compression of many digital still cameras leaves margin for deriving and applying image-adapted coded apertures that support retention of the most important frequencies after compression. These coded apertures, together with subsequently applied image processing, enable a higher light throughput than corresponding circular apertures, while preserving...