Near millimeter wave imaging/multi-beam integrated antennas

This report describes the most recent work on the theory of single element Linearly Tapered Slot Antennas (LTSAs) and Constant Width Slot Antennas (CWSAs). The radiation mechanism for these is presently well understood and allows quantitative calculation of beamwidths and sidelobe levels, provided that the antennas have a sufficiently wide conducting region on either side of the tapered slot. Appendices 4 to 7 represent earlier work on the grant. This work further elucidates the properties of arrays of CWSA elements, and the effects of coupling on the beam-shape. It should be noted that typical beam-efficiencies of 65% have been estimated, and that element spacings of about one Rayleigh unit are possible. Further, two-point resolution at the Rayleigh spacing has been demonstrated for a CWSA array in a 30.4 cm paraboloid at 31 GHz. These results underscore that interest in further studies of the radiation mechanism of tapered slot arrays. Appendix 7 constitutes a final, detailed report on the work leading to a 94 GHz seven element LTSA array imaging system, which has been reported previously in less detail. Experimental results are presented

A document review to characterize Atomic International SNAP fuels shipped to INEL 1966--1973

This report provides the results of a document search and review study to obtain information on the spent fuels for the following six Nuclear Auxiliary Power (SNAP) reactor cores now stored at the Idaho National Engineering Laboratory (INEL): SNAP-2 Experimental Reactor, SNAP-2 Development Reactor, SNAP-10A Ground Test Reactor, SNAP-8 Experimental Reactor, SNAP-8 Development Reactor, and Shield Test Reactor. The report also covers documentation on SNAP fuel materials from four in-pile materials tests: NAA-82-1, NAA-115-2, NAA-117-1, and NAA-121. Pieces of these fuel materials are also stored at INEL as part of the SNAP fuel shipments

Individual nutrition therapy and exercise regime: A controlled trial of injured, vulnerable elderly (INTERACTIVE trial)

© 2008 Thomas et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background Proximal femoral fractures are amongst the most devastating consequences of osteoporosis and injurious accidental falls with 25–35% of patients dying in the first year post-fracture. Effective rehabilitation strategies are evolving however, despite established associations between nutrition, mobility, strength and strength-related functional outcomes; there has been only one small study with older adults immediately following fragility fracture where a combination of both exercise and nutrition have been provided. The aim of the INTERACTIVE trial is to establish whether a six month, individualised exercise and nutrition program commencing within fourteen days of surgery for proximal femur fracture, results in clinically and statistically significant improvements in physical function, body composition and quality of life at an acceptable level of cost and resource use and without increasing the burden of caregivers. Methods and Design This randomised controlled trial will be performed across two sites, a 500 bed acute hospital in Adelaide, South Australia and a 250 bed acute hospital in Sydney, New South Wales. Four hundred and sixty community-dwelling older adults aged > 70 will be recruited after suffering a proximal femoral fracture and followed into the community over a 12-month period. Participants allocated to the intervention group will receive a six month individualised care plan combining resistance training and nutrition therapy commencing within 14 days post-surgery. Outcomes will be assessed by an individual masked to treatment allocation at six and 12 months. To determine differences between the groups at the primary end-point (six months), ANCOVA or logistic regression will be used with models adjusted according to potential confounders. Discussion The INTERACTIVE trial is among the first to combine nutrition and exercise therapy as an early intervention to address the serious consequence of rapid deconditioning and weight loss and subsequent ability to regain pre-morbid function in older patients post proximal femoral fracture. The results of this trial will guide the development of more effective rehabilitation programs, which may ultimately lead to reduced health care costs, and improvements in mobility, independence and quality of life for proximal femoral fracture sufferers. Trial registration Australian Clinical Trials Registry: ACTRN12607000017426

Microstrip antennas utilizing MEMS for reconfigurable polarisation states

A modern approach to an established technique is investigated for the electronic control of polarisation of microstrip patch antennas. The control is achieved by placing micro-electromechanical switches (MEMS) at appropriate locations in a patch antenna. The microwave MEMS are used to switch between open and short circuit conditions that allow reconfiguration of the modal fields. Changing the number and location of short circuit field regions changes the radiated field polarisation from linear horizontal to vertical, right hand circular or left hand polarisation. All of the polarisation states are obtained without changing the frequency of operation, input impedance or radiation pattern of the patch a

Physical aspects of mutual coupling in finite broadband tapered slot (Vivaldi) arrays

A notch antenna, or Vivaldi antennas, or also known as tapered slot antenna (TSA) is widely used as a single radiator but mostly as an array element in transmitting, receiving and combined arrays, focal-plane imaging and other system-oriented broadband applications. Full-wave analysis of such arrays is required that is a big numerical challenge because of large electrical size for such typical problems. Only infinite arrays or very small arrays are treatable with available EM tools. However, all elements of moderate in size arrays can be impacted by edge truncation because of strong mutual coupling within TSA array environment. Thus, accurate performance prediction and design can be achieved through (1) enhancing EM simulation numerical tools and (2) exploring underlying physical phenomenology of array behaviour. We follow both the above ways. This work demonstrates some basic physics related to mutual coupling is small finite arrays

Abstract Electromagnetics-Related Aspects of Signaling and Signal Processing for UWB Short Range Radios *

A numerical model of the UWB channel created by two dipole antennas is developed to characterize the antennas and the whole channel using system level concepts such as transfer functions in the frequency domain. This model is based on rigorous numerical electromagnetic (EM) analysis, thereby enabling predictions of the channel performance under impact of different antenna geometries, their spatial arrangements, and disturbance caused by diverse factors observable in practical links. These studies of channels address to a number of important issues in electromagnetic-related aspects of UWB signaling schemas and signal processing. First, pulse shaping is developed to support signal transmission across the channel with necessary temporal and spectral features, and high efficiency of energy transmission. To this end, several realistic antennas and practical short-range radio operational scenarios are considered. Second, a system-oriented approach is presented through antenna-signal-circuitry co-design. Finally, overall system performance and hardware complexity of signaling including receiver processing are evaluated. 1

Analysis of large microstrip-fed tapered slot antenna arrays by combining electrodynamic and quasi-static field models

A reduced-order model for large arrays of microstrip-fed tapered slot antennas (TSAs) is presented. The currents on the antenna conductors are modeled by a relatively small number of physics-based macro-domain basis functions through a technique which is known as the characteristic basis function method (CBFM). The array is treated as a metal-only structure, while the wideband microstrip feeds are separately modeled using quasi-static circuit models. It is demonstrated that, even though the dielectric-supported feeds are non-shielded and therefore form an integral part of each radiating antenna element, the feeds can be modeled independently from the strongly coupled antenna elements. Validation of the combined antenna-feed model has been carried out through the measurements of several practically realized TSA arrays, among them a 8 7 7 7 2 dual-polarized array. The results demonstrate good agreement over a large scan range, as well as over a wide frequency band. The polarization-discrimination capabilities of the antenna, when operating in phased-array mode, have been analyzed in the context of radio-astronomical applications