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 41 for “"Circular Polarization"”.
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Development of compact circular polarized antenna for WLAN application
Matching the polarization in both the transmitter and receiver antennas is important in terms of decreasing transmission losses. The use of circularly polarized antennas presents an attractive solution to achieve this polarization match which allows for more flexibility in the angle between …
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Reconfigurable Wideband Circularly Polarized Microstrip Patch Antenna for Wireless Applications
… of rectangular microstrip patch antenna to have circular polarization agility with wideband performance, for wireless applications are presented. First, a new technique to achieve circularly polarized (CP) probe feed single-layer microstrip patch antenna with wideband characteristics is proposed. …
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Design and Construction of an Optical Polarimeter for the Study of Ice-like Analogs using Near Zero Phase Angle Measurements
… and other Icy Galilean satellites exhibit high circular polarization ratios with decreasing phase angle that indicates the possible presence of icy deposits in the polar craters. An examination of powder samples with known composition and grain sizes was undertaken to try and further understand …
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Multifilar Hemispherical Helical Antennas
… moderate gain, largely real input impedance and circular polarization when operating in the axial mode regime. A modified form of the helix, the spherical helix, has been shown to yield similar polarization and gain characteristics over a narrow bandwidth but a much larger beamwidth. This …
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Low Profile, Printed Circuit, Dual-Band, Dual-Polarized Antenna Elements and Arrays
Dual-band antenna elements that support dual-polarization provide ideal performance for applications including space-based platforms, multifunction radar, wireless communications, and personal electronic devices. In many communications and radar applications, a dual-band, dual-polarization antenna …
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Dual-polarization meteorological radar: theory and design
… and can be applied to systems using linear, circular, or elliptical polarization. The general formulation reduces to results previously published in the literature for linear polarization differential reflectivity (Z<sub>DR</sub>) and for circular polarization depolarization ratio ( CDR). …
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The Structure and Polarization Properties of the SiO Masers in the Extended Atmosphere of R Aquarii
… symbiotic binary R Aquarii. Four epochs of full-polarization observations were recorded using the Very Long Baseline Array a facility the National Radio Astronomy Observatory. The first high-resolution images of the extended atmosphere of a Mira variable in a symbiotic binary have been produced. …
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Novel feeds for microstrip and slot antennas: Theory and experiment
… to the calculation of the feed locus for circular polarization operation. Simple design formulas are obtained for CP electromagnetically excited microstrip antennas.
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The Spiro-Helical Antenna
… indicate that the proposed antenna provides circular polarization and high gain over a wide frequency range. For example, when the number of turns is 10, a gain of 11-14 dB, a boresight axial ratio of less than 3 dB, and a half-power beamwidth of about 40 degrees are achieved over a 30% …
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Antenna effects on indoor wireless channels and a deterministic wide-band propagation model for in-building personal communication systems
… in wide-band channels. Research has shown that circular polarization (CP) is more robust in combating multipath than linear polarization in line-of-sight channels. One objective of this thesis is to study the effects of antenna polarization and antenna pattern on multipath delay spread and path …
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Optical Polarization Studies Of Latex Beads In Aqueous Solution: An Analog For Radar Scattering In Water-Ice Medium
… sense (SC), and opposite sense (OC) backscatter circular polarization coefficients, circular polarization ratio (CPR), and degree of linear polarization (DLP) of spherical latex (non-dye) beads of varying sizes and volume concentrations (v/v) in aqueous solutions (λ=0.8μm) in water. We leverage …
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Design and Analysis of Circularly Polarized Electrically Small Antennas
… many satellite based communication applications, circular polarization in antennas is needed for efficient communication. In this thesis, the miniaturization technique known as T-top loading is utilized on two novel antenna designs. One design is an electrically small, circularly polarized planar …
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A Ridge-fed Conical Horn Antenna for Small Satellites
… from 2GHz to 13GHz. The design must exhibit circular polarization and drive a gain equal to or more than 10dB with a certain beamwidth. Mechanical attributes of a practical deployment mechanism has to be taken into consideration to make the design robust for autonomous deployment once on …
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Wide Viewing Angle Liquid Crystal Displays
… the applicability of the broadband and wide-view circular polarizer, the device configuration of the broadband and wide-view circular polarizer is significantly simplified by the application of biaxial compensation films. The produced states of polarization remain close to the ideal circular …
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Indoor wide band radio wave propagation measurements and models at 1.3 ghz and 4.0 ghz
… determine the effects of antenna directivity and polarization on propagation parameters. On average, line-of-sight indoor channels offer 8 dB of cross-polarization discrimination, whereas obstructed environments offer less than 3 dB. Directional antennas provide a significant reduction in rms …
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Accretion and outflow in black-hole x-ray binaries
… plasma or electron-positron plasma. Circular polarization (CP) is a good diagnostics for understanding the particle composition of radio jets. Therefore we have observed the circular polarized flux densities of SS433 using the Australia Telescope Compact Array (ATCA) for a broad range …
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Observational and theoretical studies of SiO maser polarization toward late-type evolved stars: Insights from EVPA reversal features
The detailed mechanisms responsible for the polarization of SiO masers toward late-type evolved stars continue to be a subject of debate. Possible primary sources include the local magnetic field or anisotropic pumping, while additional polarization may arise due to conversion from linear to …
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A study of the polarimetric characteristics of planar chiral mesoscopic structures
… amplifier techniques is used to measure the polarization states alteration. Subsequently, the polarization states are mathematically analyzed using Stokes parameters and Muller matrices. In order to minimize the measurement time, the microscope polarimeter was optimized by using LabView to …
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Magnetic X-ray Reflectivity
… x-ray reflectivity combines the strong magnetic circular dichroism (MCD) effect, significantly enhancing the magnetic sensitivity of x-rays, with the technique of conventional specular reflectivity, a well established tool for the structural studies of the chemical makeup of thin films and …
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Development of conformal reconfigurable metamaterial-based antennas
… meander lines - can be reconfigured into four polarization states. The proposed metasurface becomes a reflector with emptied channels, whereas exhibits linear to cross polarization conversion (or linear to circular polarization conversion) properties when the top (or bottom) layer is filled …
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