Shifted band beamformer: Theory and concept

Dual-beam Wide-band Beamformer with Integrated Antenna Array

As part of the development of a new international radio-telescope SKA (Square Kilometre Array), three phased-array prototypes with increasing complexity have been developed. The final SKA telescope will consist of more than one million receiving antenna elements and will operate in the frequency range of 200 to 2000 MHz. One of the challenges of the next generation radio telescopes for astronom...

String perturbation theory around dynamically shifted vacuum

In some string theories, e.g. SO(32) heterotic string theory on Calabi-Yau manifolds, a massless field with a tree level potential can acquire a tachyonic mass at the one loop level, forcing us to quantize the theory around a new background that is not a solution to the classical equations of motion and hence is not described by a conformally invariant world-sheet theory. We describe a systemat...

Multi-beam Adaptive Beamforming Using a C-band Receiver Array and a Frequency-domain Digital Beamformer

This paper introduces a novel architecture of a multi-beam adaptive beamformer for SDMA (space division multiple access) applications. Combined with a 5.8 GHz eight-element RF front-end, digital beamforming performance using the proposed frequency-domain multi-beam beamformer is demonstrated in post processing. The DOA estimation based on the ESPRIT algorithm and simultaneous dual-beam forming ...

Part I: Concept and Theory

Solving Shifted Linear Systems with Gmres and Applications to Lattice Gauge Theory Solving Shifted Linear Systems with Gmres and Applications to Lattice Gauge Theory 1. Introduction

of a matrix M 2 C nn and a vector r 2 C n are identical for all 2 C. This fact can be used in Krylov subspace iterative methods (where the