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 18 of 18 for “"Horn antenna"”.
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Variable permittivity dielectric material loaded stepped-horn antenna
Stepped-horn antenna loaded with dielectric material of variable permittivity is proposed to improve radiation characteristics and/or to increase the electrical dimensions of the radiating structure compared to unloaded empty one. A hybrid numerical technique is used to analyze such an antenna. The …
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A Ridge-fed Conical Horn Antenna for Small Satellites
… presented a myriad of exciting opportunities for antenna engineers to come up with alternative solutions to meet the ever evolving needs of the CubeSat applications. The advancement of technology has enabled small satellites to carry out sophisticated missions such as space weather monitoring, …
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Finite-difference time-domain analysis of horn antenna scattering
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; and, (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 1998.
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NeXtRAD antenna design: X-Band dual polarised conical horn antenna
… and implementation of a dual polarised X-band antenna. The desired specifications include a centre frequency of 8.5 GHzand a 10_ azimuth-half power beam width in both vertical and horizontal polarisations. Other requirements include peak power handling of 400 W over a 50 MHz instantaneous …
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An optimized dual-polarized quad-ridges horn antenna with pyramidal sidewalls
It is well known that quad-ridged horn antennas in general have impedance and radiation characteristics that are significantly worse than that of their double-ridged counterparts. Normally a voltage standing wave ratio (VSWR) of 3 over the operational bandwidth is used for the design specification …
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Electromagnetic Analysis of Horn Antennas in the Terahertz region
… modelling techniques to the analysis of horn antenna characteristics over the terahertz range, 0.1 THz to 5 THz. The mode matching technique based on a scattering matrix approach to describe beam propagation in both the forward and backward direction is applied to the analysis of conical …
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Design of an Ultra-Wideband Spiral Antenna for Ground-Penetrating Microwave Impulse Radar Applications
… Radar (MIR) capable of IED detection requires antennas capable of transmitting sub-nanosecond pulses over ultra-wideband (UWB) frequency ranges. This thesis investigates the suitability of a novel MIR antenna for high-accuracy ground-penetrating radar (GPR) applications. Key GPR antenna …
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HIGH EFFICIENCY AXIAL DIFFRACTION OUTPUT SCHEMES FOR THE A6 RELATIVISTIC MAGNETRON
… axial power extraction through a mode-converting horn antenna, resulting in improved efficiency (30% improved to 70%) and greater output power handling capability (sub-gigawatt improved to multi-gigawatt) without breakdown. In addition, axial extraction results in a more compact profile that is …
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Design and Development of Planar Antennas and Dielectric Devices for use at W Band Frequencies
… in this thesis is the development of planar antennas for observations at W band frequencies. A large portion of this analysis is based on the specific development of devices as part of an ESA research package entitled “New Technology High Efficiency Horn Antennas for CMB Experiments and …
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A Study of GPR Performance in the Presence of Buried Biomass
… a wideband, polarimetric, dielectric-loaded horn antenna. In the measurements, the antenna was scanned along the ground surface transverse to a horizontal steel rod buried at different depths. The data were processed to reveal scattering characteristics of empty soil and soil with roots. For …
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3D intrawall imaging using backprojection for synthetic aperture radar (SAR)
… conduits and piping. This is done by moving the antenna system across the wall surface to create SAR images using backprojection. The radar used two different types of antennas, a log periodic dipole array (LPDA) antenna and horn antenna. The horn antenna performed well in the experiments, …
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Design rectenna for wireless energy harvesting
… which is a combination of a rectifier and an antenna, is a device to harvest wireless energy in the air. This thesis is concentrated on the analysis, design and measurement of compact rectennas for Wi-Fi (RF) wireless energy harvesting applications. The objectives of this project is to study …
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The feasibility of using EM waves in determining the moisture content and factors effecting measurements in building fabrics
… to model the microwave sensor. The pyramidal horn antenna was chosen as the preferred antenna for this work owing to higher gain, directivity and overall performance. Different building materials and structures have been made in a laboratory environment to determine the levels of moisture …
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Microwave Interferometer and Refractometer for the WB-8 Polywell Fusion Device
… beam into the test chamber. The beam leaving a horn antenna is approximately Gaussian. Using Gaussian optics a lens can be used to focus the beam in order to probe the center of the plasma and provide sufficient energy at the receiver. While the interferometer provides an average density, a more …
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Analysis and Measurement of Horn Antennas for CMB Experiments
… of millimetre and sub-millimetre wave horn antennas for Cosmic Microwave Background (CMB) experiments is presented. This computational work particularly concerns the analysis of the multimode channels of the High Frequency Instrument (HFI) of the European Space Agency (ESA) Planck …
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Electromagnetic Techniques for Analysis and Design of Ultra Sensitive Receivers for Far-Infrared Astronomy
… analysis of SAFARI-like multi-mode feed horns, and the absorber coupled superconducting TES (transition edge sensor) bolometers that are typically used in far-IR receivers. Special attention is given to the integrating cavity backshorts that serve to increase pixel efficiency, and new …
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Concept Demonstrator for MeerKAT Operation from 14.5 to 20 GHz
… is presented. MeerKAT is a 64 element telescope antenna array consisting of offset-fed Gregorian reflector antennas with a 13.5 m main reflector and 3.8 m sub-reflector. Currently, the MeerKAT is planned to operate up to 14.5 GHz. However, the reflector surface accuracy of 0.6 mm RMS achieved for …
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Investigation of Horn Optimisation, Simulation and Measurement Techniques, with Application to Integrating Cavity Based Pixel Design
… missions require high performance focal plane antennas, a position traditionally filled using corrugated horns. Future missions will require large arrays of high performance anten- nas, and the thermal and mechanical penalties associated with high mass corrugated horns (in addition to their …