Smart antenna is one way to solve the major problems of wireless and cellular communication, like multipath propagation and co-channel interference. The basic requirement of cellular communication is transmit signal only in desired direction rather than in Omni direction to minimize the interference and fading effect. Optimization of patch array antenna for cellular communication will be consid...

This paper shows the capability the alternating direction method of multipliers (ADMM) has to track, in a distributed manner, the optimal down-link beam-forming solution in a multiple input multiple output (MISO) multi-cell network given a dynamic channel. Each time the channel changes, ADMM is allowed to perform one algorithm iteration. In order to implement the proposed scheme, the base stati...

Laser forming as a springback-free and noncontact forming technique has been under active investigation over the last decade. Previous investigations are mainly focused on forming of large and thick workpieces using high power lasers, with less work on precision, micro-scale bending of small and thin sheets. In this work, a 4 W continuous wave argon ion laser is used as the energy source, and t...

Direct-sequence code-division multiple-access (DSCDMA) cellular systems, such as Wideband CDMA (WCDMA), are limited in performance by interference. Several types of Rake Receivers like A-Rake, S-Rake, P-Rake, Adaptive frequency Rake, Time frequency Rake, Conventional MMSE Rake and Adaptive MMSE rake are used for WCDMA. A Beam formerRake receiver can be an effective solution to provide the recei...

Computer -generated holograms (CGHs) are used in a number of important optical technology application areas such as holographic optical elements, optical processing and computing, optical testing, image and information display, beam forming, and beam scanning. Many different CGH fabrication devices (e.g., laser beam scanners, electron beam writers) and facilities have been developed and are in ...

A laser excited, sub-nanosecond, pulsed electron beam system is described. The system consists of a high voltage pulser and a coaxial triggered spark gap. The liquid spark gap discharges into a pulse forming line designed to produce and maintain a flat voltage pulse of 1ns duration on the cathode of a photodiode. A synchronized laser is used to illuminate the photo-cathode to produce an electro...

We present a highly purposive technique to optically induce periodic photonic lattices enriched with a negative defect site by using a properly designed nondiffracting (ND) beam. As the interference of two or more ND beams with adequate mutual spatial frequency relations in turn reproduces an ND beam, we adeptly superpose a hexagonal and a Bessel beam to create the ND defect beam of demand. The...

The use of a two stage crystal collimation system in the RHIC yellow ring is examined. The system includes a copper beam scraper and a bent silicon crystal. While scrapers were installed in both of the RHIC rings before the year 2000 run, the crystal is installed for the 2001 run in one ring only, forming a two stage collimation system there. We present simulations of the expected channeling th...

Intrinsic spherical aberrations of electron lenses have been the major resolution limiting factor in electron microscopes for several decades. While effective correctors have recently been implemented, an alternative to correct these aberrations is to circumvent them by scaling down lens dimensions by several orders of magnitude. We have fabricated electrostatic lenses exhibiting one micrometer...