Perturbations to conventional two beam X-ray diffraction arising from multibeam scattering effects have been studied theoretically. A simple analytical expression for the diffracted wave field and intensity near a multiple excitation is derived by using the perturbation theory of scattering of electromagnetic waves. Although it cannot be applied to the center of a multibeam diffraction peak, it...

The combined use of acoustic backscatter and bathymetric data generated by multibeam echo-sounders provides a powerful tool to investigate substrate characteristics at fine spatial scales across large areas. New methods are now required to assess the links between the identification of physical substrate classes from multibeam data with visually classified classes from AUV data. In this paper, ...

Currently, spatial signal processing for adaptive source separation and interference cancellation are extensively discussed for application in future mobile radio systems. ESPRIT-type algorithms are especially concerned because of their low arithmetic complexity and their inherent ability for superresolution estimation of the direction of arrival (DoA) [1]. The latter is also true for mobile ra...

Linear precoding exploits the spatial degrees of freedom offered by multi-antenna transmitters to manage interferences between multiple co-channel users. The adoption of precoding in practical systems, however, entails a series of practical barriers. Amongst several issues, the focus herein is on the non-linear dependence of the input versus the output power of the efficient and reliable amplif...

Smart Antenna with RF beamforming capability can greatly improve the performance of the vehicle communication system by providing better link quality and high immunity to interference. Butler Matrix is a well-known beamforming network. It can be used for multibeam antennas. The Butler Matrix increases the system capacity and provides higher signal to interference ratio, consequently enhancing t...

We explore the multicast lifetime capacity of energy-limited wireless ad hoc networks using directional multibeam antennas by formulating and solving the corresponding optimization problem. In such networks, each node is equipped with a practical smart antenna array that can be configured to support multiple beams with adjustable orientation and beamwidth. The special case of this optimization ...

A multibeam optical beamformer capable of controlling a phased-array antenna in receive/transmit mode is proposed. The processor can be programmed to sweep the antenna aperture following an independent angular sequence for each radio-frequency (RF) beam. A two-beam two-channel 3-bit version of the beamformer has been experimentally demonstrated. The optical beamformer processes two independent ...

[email protected] Abstract— In this paper we consider the capacity of a set of portable stations sharing a single indoor radio channel. The stations communicate with a basestation which is equipped with a smart antenna operating in multibeam SDMA/TDMA mode. Both theoretical models and measured data from an experimental testbed are presented. The experimental system operates at 1.86 GHz and uses ...