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 13 of 13 for “"frequency tunable"”.
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Frequency-tunable second-harmonic submillimeter-wave gyrotron oscillators
… the design and experimental demonstration of frequency-tunable submillimeter-wave gyrotrons operating in continuous wave (CW) at the second harmonic of the electron cyclotron frequency. An unprecedented continuous frequency tuning range of more than 1 GHz has been achieved in both a 330- and a …
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Generation of ultrahigh frequency acoustic waves for the characterization of complex materials
… which interact strongly with ultrahigh frequency acoustic waves and creating the anomalies. The model has been found to well reproduce the measured anomalous thermal conductivity of silica glass. Separately, an experiment which utilizes impulsive stimulated thermal scattering is used to …
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New modeling of compact, high-efficiency, and widely-tunable gas-phase terahertz lasers
… to have intrinsically low efficiency, not tunable in frequency, and large sizes. In this thesis, we introduce a compact, frequency-tunable source of terahertz radiation with high efficiency. We first present both an innovative theoretical model and experimental validation of a Methyl …
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Microstruture & High Frequency Property of Fe- & Co- Based Nano-Grain Thin Films
… In order to apply magnetic thin films at high frequency range, it is essential to measure the high frequency permeability and understand the electromagnetic properties that can control the high frequency permeability. In this research, the permeability measurement method at high frequency for …
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Generation of high power single-cycle and multiple-cycle terahertz pulses
… generation of high power single-cycle and frequency-tunable multiple-cycle terahertz (THz) pulses pumped with near-infrared ultrashort optical pulses at 1 kHz and 10 Hz repetition rates. Single-cycle THz pulses with sub-picosecond duration and more than 50 pJ pulse energy, and …
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Theoretical and Experimental Studies of Manipulation of Elastic Waves in Helix Metamaterials
Helix metamaterials; Wide low-frequency bandgap; Controllable design; Laser vibration measurement; Strong vibration attenuation; Carrera Unified Formulation Abstract Elastic metamaterials exhibit mechanical properties unattainable in natural materials and demonstrate vast potential in vibration and …
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EMI measurement and modeling techniques for complex electronic circuits and modules
… was developed.</p> <p>In the second paper, a frequency-tunable resonant magnetic field probe was designed in the frequency range 900-2260 MHz for near-field scanning applications for the radio frequency interference studies by using a varactor diode providing the required capacitance and the …
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Reconfigurable tunable microwave devices using liquid crystal.
… medical devices. The shortage in the available frequency spectrum for radio communications, the demand for portable wireless devices, and the requirement for more functionality in an even smaller volume, requires the development of new concepts in RF technology. One ideal pathway towards …
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Miniaturised bandpass filters for wireless communications
… stringent specification is imposed upon the frequency utilization of wireless devices. New challenges are constantly being discovered in the development and realization of RF and microwave filters, which have not only sustained but fuelled microwave filter research over the many years. These …
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Ultrafast photo-acoustic spectroscopy of super-cooled liquids
… dynamics are centered uniquely in the gigahertz frequency range. The experimental approach used a unique laser pulse shaping technique and, in the case of shear acoustic waves, a crystallographically canted metal transducer layer, to generate frequency tunable compressional and shear acoustic …
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Integrated Tunable LC Higher-Order Microwave Filters for Interference Mitigation
… as the traditional off-chip filters are fixed frequency and bulky. Therefore, tunable filtering is a critical building block for the reconfigurable RF front-ends and on-chip implementations are needed to meet size and weight constraints. On-chip passive components are lossy, especially …
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Parity-Time Symmetry in Lasers and Optoelectronic Oscillators
… OEO in a single physical loop, enabling frequency-tunable single-mode oscillations from 2 to 12 GHz with excellent phase noise performance, thereby eliminating the need for ultra-narrowband RF filters. While these single-loop designs prove the feasibility of PT symmetry for mode …
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Filter Design for Interference Cancellation for Wide and Narrow Band RF Systems
In radio frequency (RF), filtering is an essential part of RF transceivers. They are employed for different purposes of band selection, channel selection, interference cancellation, image rejection, etc. These are all translated in selecting the wanted signal while mitigating the rest. This can be …