Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"K-band"”.
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K-band lithium niobate microelectromechanical system hybrid filters
… as well as the first demonstration of a wideband hybrid monolithic acoustic filter in the K-band, which exceeds the limitation of electromechanical coupling on the fractional bandwidth (FBW) of acoustic filters. The hybrid filter utilizes the co-design of electromagnetic (EM) and acoustic to …
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Design of low-power K-band circuits in CMOS technology
… Anderseits können Frequenzteiler mit großer Bandbreite und geringem Leistungsverbrauch schwierig realisiert werden. Infolge des Flickerrauschens und der einhergehenden schlechten Rauschzahl gestaltet sich des Weiteren auch das direkte Heruntermischen in das Basisband mit sog. …
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Ultrafast laser fabrication of a K-band integrated optic 2-telescope beam combiner for astronomical interferometry
… applications. A fibre-connectorised K-band 2-telescope integrated optics (IO) beam combiner is designed and fabricated in commercial Infrasil® glass (IG) to update the existing JouFLU beam combiner at the Center for High Angular Resolution Astronomy (CHARA) array. A liquid crystal on …
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The effect of applied uniaxial stresses on the optical absorption of F centers in alkali halides
… By measuring the first moment change of the F band due to uniaxial stresses applied in (100) and (1l0) directions,' the coupling of the F center excited state to lattice distortions of tetragonal and trigonal symmetry is evaluated. By measuring the third moment change due to the same ~pplied …
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Improving the Resolution and Sensitivity of Microwave Astronomical Observations
… TolTEC Fields and Filaments survey and BVEX, a K-band balloon-borne Very Long Baseline Interferometry (VLBI) station where I will be presenting my design and sensitivity requirements for the K-band receiver. While TolTEC will deliver science-ready maps of the linear Stokes parameters I, Q, and U …
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Substrate integrated waveguide antenna systems
… for current and future systems operating in K-band and above. Therefore, all the work presented in this dissertation focuses on SIW technology. Five di erent antenna systems are proposed to verify the advantages of using SIW technology. First, a novel K-band end- re SIW circularly polarized …
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A detailed infrared study of the star forming region NGC2071 IRS
… region are presented in this thesis. A 5' x 9' K band image and contour map of NGC2071 are presented, as is the first high resolution K band polarimetry of the cluster of near-IR sources in the core of this bipolar outflow. The nature of these IR sources are analysed and discussed individually and …
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A Wide Band Model for the Absorption Coefficient Cumulative Distribution Function of Water Vapor and Carbon Dioxide
… for the 1.38, 1.87, 2.7 and 6.3 micron bands of water vapor are developed for a wide range of pressures and temperatures from 300 K to 2900 K. The parameters for the rotational band of water vapor include temperatures from 300 K to 1900 K. Band parameters for the 2.0, 2.7, 4.3, 9.4, 10.4 …
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Calibration of MIDI, the Mid-infrared Interferometer for the VLTI
… stellare Langbasisinterferometrie im N-Band (8...13µm) durchführen. Im Vorfeld des Aufbaus von MIDI waren einige vorbereitende Aufgaben zu lösen, die die Kalibrierung des Instruments im Labor betrafen. Die interne Verzögerungsstrecke, die eine wesentliche Untereinheit von MIDI darstellt, …
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Doppelsternhäufigkeit unter röntgenselektierten T-Tauri-Sternen
… Scorpius-Centaurus vor. Die Sterne wurden im K Band (2.2 µm) mit Hilfe von Speckle-Interferometrie und Direktaufnahmen beobachtet. Die Beobachtungen in Taurus-Auriga erlauben uns, alle Begleiter mit Abständen zwischen 0.13 und 13 Bogensekunden bis zu einer Magnitudendifferenz von 2.5 zu finden. …
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The near infrared luminosity function of the Norma Cluster
In this thesis, a near infrared KB-band photometric catalogue of galaxies in the Nonna cluster is presented. The survey of the cluster covers an area of '" 0.8h702 Mpc2, and is estimated to be complete to a magnitude of MK. ⋨-19 mag; this extends into the dwarf regime, 6 magnitudes below M'k •. The …
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Design Of A Material Test Kit For Use From 1.6 Ghz To 26.5 Ghz And Its Use In Evaluation Of Dielectric Properties Of Foam Core Materials Used In Sandwich Composites
… N5242-X vector network analyzer (VNA) in various bands such as R-band, S-band, C-band, G-band, C-band, X-band, P-band and K-band i.e. the dielectric properties of these materials are measured in the frequency range of 1.70 GHz to 26.5 GHz. The rectangular waveguide (RWG) is used for the …
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Designing a beam combiner for faint limiting magnitudes in optical interferometry
… (MROI). FOURIER is a three telescope, J, H and K band image plane beam combiner. I first highlight the scientific motivation for a faint limiting magnitude beam combiner and the design requirements this placed on FOURIER. This is followed by a discussion of how the optical design was derived from …
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Frequency scaling of rain attenuation on satellite links in the Ku/Ka-bands using OLYMPUS satellite data
… of the eventual need to exploit higher frequency bands. Most satellite communications traffic now use C-band (4-8 GHz) and Ku-band (12-18 GHz). The next approved, yet largely unused, frequency allocation for domestic use is in the K-band (18-27 GHz) to Ka-band (27-40 GHz). At these higher …
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Design and development of an airborne microwave radiometer for atmospheric sensing
… The NPOESS Aircraft Sounder Testbed - K-band (NAST-K) is a passive microwave radiometer operating over approximately 200 MHz bandwidth centered at 23.8 GHz and 31.4 GHz, whose data can be used to find surface water, humidity, and temperature conditions. NAST-K flies along with the …
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Flare stars in the solar vicinity
… m class telescopes (e.g. VLT or Keck). In the K-band the achievable angular resolution is about 50 mas which corresponds to 5 AU at a star closer than 100 pc; 5 AU is about the distance between the Sun and Jupiter. This possibility can be used to study surrounding material such as disks made up …
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The Environments of Active Galactic Nuclei
… and more luminous than ordinary galaxies. The K-band luminosities of the host galaxies are between 2 and 3 times more luminous than an M galaxy indicating that they are drawn from the exponential tail of the K-band galaxy luminosity function. No significant difference is found between the …
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EMI measurement and modeling techniques for complex electronic circuits and modules
… results.</p> <p>In the third paper, a wideband microwave method was developed as a means for rapid detection of slight dissimilarities (including counterfeit) and aging effects in integrated circuits (ICs) based on measuring the complex reflection coefficient of an IC when illuminated with …
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Seyfert and starburst activity in galaxies: Modeling and analysis
… obscured stars in the Milky Way. We used the CO band at 2.3μm to estimate the contribution from red supergiants to the total K-band flux in the central regions of 46 Seyferts from the CfA redshift survey, based on new infrared spectroscopy (R ∼ 700). We removed the non-stellar contribution for 16 …
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Test of the Infrared Wide-Field Camera OMEGA2000 and its Application for an Extragalactic Survey
… Focal plane array with a sensitivity from z to K band. In the first part of the thesis, we discuss the work aimed at optimizing the operation of the HAWAII-2 detector installed in the camera. We tested the operation of three speciemen from the HAWAII-2 family and compared their performances with …
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