Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

The wire grid microstrip antenna

Abstract: A description is given of an antenna consisting of an interconnected wire grid formed by etching metallic lines on a dielectric sheet backed by a metallic ground plane. The theory of operation, analytical model, and experimental findings for this approach to a printed array are described. The device is low cost, light weight, and has sufficient bandwidth to be of use in a variety of applications. An analytical model is developed which establishes transmission line equivalent circuits for the wire grid elements. Current distributions determined from the model are shown to predict accurately the measured pattern performance of a typical implementation. The bandwidth as established by various pattern parameters is quantitatively assessed. Particular emphasis is given to methods of amplitude control through control of line impedances. A particular design implementation is presented for a five-wavelength circular array with independent quadrant control. Measured results from this configuration are compared to theory.

Electronic sight for firearm, and method of operating same

Abstract: A firearm sight receives information regarding a factor, and then automatically adjusts the relative positions of a digital reticle and an image on a viewing section to compensate for the influence of the factor on a projectile trajectory. A different feature involves automatically adjusting a characteristic of the reticle based on the image. Another feature involves automatically adjusting the digital image to distinguish a portion thereof aligned with the reticle from an adjacent portion thereof. Yet another feature involves causing the firearm sight to generate an audible sound. Still another feature involves presenting information on the viewing section which represents the position of the firearm sight on the surface of the earth.

Method and apparatus for capture and sequester of carbon dioxide and extraction of energy from large land masses during and after extraction of hydrocarbon fuels or contaminants using energy and critical fluids

Abstract: A closed loop system for increasing yield, reducing post process pollution, reducing energy consumed during and after extraction of fuels or contaminants in formations and for sequestering of carbon dioxide CO2 from various sources is converted to a critical fluid for use as a flushing and cooling medium. Electrical energy heats a hydrocarbon rich formation resulting in the extraction of hot fluids which are fed to heat exchangers, gas/liquid separator, and steam turbine whereby oil, electric power, carbon dioxide and methane are produced for reuse in the system or for external use. Further, a method for sequestering of carbon dioxide in a formation comprises the steps of injecting CO2 into the reservoir, flushing with cool pressurized CO2 for heat removal, infiltrating with ultra- fine low density suspended catalyst particles of dry sodium hydroxide in CO2, pumping water moistened CO2 into the reservoir to activate the catalysts, binding the CO2 with reacting materials and capping the reservoir.

The ACS LCID Project. V. The Star Formation History of the Dwarf Galaxy LGS-3: Clues to Cosmic Reionization and Feedback

Abstract: We present an analysis of the star formation history (SFH) of the transition-type (dIrr/dSph) Local Group galaxy LGS-3 (Pisces) based on deep photometry obtained with the Advanced Camera for Surveys onboard the Hubble Space Telescope. Our observations reach the oldest main-sequence turnoffs at high signal to noise, allowing a time resolution at the oldest ages of σ ~ 1.1 Gyr. Our analysis, based on three different SFH codes, shows that the SFH of LGS-3 is dominated by a main episode ~11.7 Gyr ago with a duration of ~1.4 Gyr. Subsequently, LGS-3 continued forming stars until the present, although at a much lower rate. Roughly 90% of the stars in LGS-3 were formed in the initial episode of star formation. Extensive tests of self-consistency, uniqueness, and stability of the solution have been performed together with the IAC-star/IAC-pop/MinnIAC codes, and these results are found to be independent of the photometric reduction package, the stellar evolution library, and the SFH recovery method. There is little evidence of chemical enrichment during the initial episode of star formation, after which the metallicity increased more steeply reaching a present-day value of Z ~ 0.0025. This suggests a scenario in which LGS-3 first formed stars mainly from infalling fresh gas, and after about 9 Gyr ago, from a larger fraction of recycled gas. The lack of early chemical enrichment is in contrast to that observed in the isolated dSph galaxies of comparable luminosity, implying that the dSphs were more massive and subjected to more tidal stripping. We compare the SFH of LGS-3 with expectations from cosmological models. Most or all the star formation was produced in LGS-3 after the reionization epoch, assumed to be completed at z ~ 6 or ~12.7 Gyr ago. The total mass of the galaxy is estimated to be between 2 and 4 × 108 M ☉ corresponding to circular velocities between 28 km s–1 and 36 km s–1. These values are close to but somewhat above the limit of 30 km s–1 below which the UV background is expected to prevent any star formation after reionization. Feedback from supernovae (SNe) associated with the initial episode of star formation (mechanical luminosity from SNe Lw = 5.3 × 1038 erg s–1) is probably inadequate to completely blow away the gas. However, the combined effects of SN feedback and UV background heating might be expected to completely halt star formation at the reionization epoch for the low mass of LGS-3; this suggests that self-shielding is important to the early evolution of galaxies in this mass range.