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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Bandwidth enhancement of microstrip antenna with parasitic element.

January 1991 (has links)
by Au Tsien Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 100-101). / Acknowledgments / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Analysis of Linearly Polarized Stacked Rectangular Microstrip Antenna / Chapter 2.1 --- Green's Function Formulation --- p.4 / Chapter 2.1.1 --- Field Components --- p.5 / Chapter 2.1.2 --- Boundary Conditions --- p.7 / Chapter 2.2 --- Galerkin's Method --- p.22 / Chapter 2.3 --- Numerical Computation --- p.27 / Chapter 2.4 --- Illustrative Results --- p.40 / Chapter Chapter 3 --- Analysis of Circularly Polarized Stacked Rectangular Microstrip Antenna / Chapter 3.1 --- The Range of Applications --- p.70 / Chapter 3.2 --- Analyzed Results and Discussion --- p.71 / Chapter Chapter 4 --- Conclusion --- p.98 / Reference --- p.100 / Appendix / Chapter A1 --- List of Symbols --- p.102 / Chapter A2 --- Publication List of the studies --- p.106
12

Novel synthesis and diagnosis of generalized Chebyshev narrow-band coupled resonator filter. / Novel synthesis & diagnosis of generalized Chebyshev narrow-band coupled resonator filter

January 2006 (has links)
by Meng Wei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 115-119). / Abstracts in English and Chinese. / Abstract / Acknowledgements / Table of Contents / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Overview of Microwave Filter --- p.1 / Chapter 1.2 --- Introduction to Synthesis and Diagnosis of Generalized Chebyshev Coupled Resonator Filters --- p.3 / Chapter 1.3 --- Original Contributions --- p.5 / Chapter 1.4 --- Thesis Organization --- p.6 / Chapter 2. --- Fundamental Theory --- p.7 / Chapter 2.1 --- Generalized Chebyshev Polynomial --- p.7 / Chapter 2.2 --- Cross Coupled Resonator Network --- p.19 / Chapter 2.3 --- N x N Coupling Matrix Synthesis --- p.22 / Chapter 2.4 --- Similarity Transformation --- p.28 / Chapter 2.5 --- N + 2 Transversal Network Synthesis --- p.34 / Chapter 2.6 --- Example --- p.39 / Chapter 2.7 --- Summary --- p.46 / Chapter 3. --- Analytical Diagnosis of Narrow-Band Coupled Resonator Filters --- p.47 / Chapter 3.1 --- Introduction --- p.47 / Chapter 3.2 --- Extended Realizability Conditions --- p.50 / Chapter 3.3 --- Filter Circuit Model Extraction with Finite Q Value --- p.57 / Chapter 3.4 --- Diagnosis of a Dual-Mode Circular Waveguide Filter --- p.64 / Chapter 3.5 --- Diagnosis of a In-Line Waveguide Filter --- p.69 / Chapter 3.6 --- Application in Tuning a Sixth Order Dual-Mode Filter --- p.74 / Chapter 3.7 --- Future Work --- p.82 / Chapter 3.8 --- Summary --- p.83 / Chapter 4. --- Hybrid Synthesis of Microwave Coupled Resonator Filters --- p.84 / Chapter 4.1 --- Introduction --- p.84 / Chapter 4.2 --- A Hybrid Approach --- p.86 / Chapter 4.3 --- Matrix Transformations --- p.90 / Chapter 4.4 --- Application of Proposed Method --- p.94 / Chapter 4.5 --- Future Work --- p.100 / Chapter 4.6 --- Summary --- p.101 / Chapter 5. --- Conclusion --- p.102 / Appendix --- p.104 / References --- p.115 / Author's Publications --- p.120
13

Microwave blanching and reheating of foods

Fakhouri, May O. January 1992 (has links)
No description available.
14

Experimental and theoretical investigations of microwave heating

Kota, Bhagat Chandra 30 September 2004 (has links)
In this work we proposed the governing equations for describing the microwave heating process where the complex interactions between the thermo-mechanical and electromagnetic fields are taken into account. Starting point are the general balance laws of mechanics and electrodynamics. Transient and spatial temperature profiles of liquids (water and corn solution) inside a cylindrical container during microwave heating at 2450 MHz were measured. Transient temperature rise at a given location was almost linear. The slowest heating region was at the container bottom due to small energy penetration through the bottom. Numerical simulations were carried out for microwave heating of 2D cylinders of pure water with internal convection in the liquid regions. The results are found to be consistent with those of the experiments. A generalized theoretical model was formulated for the process of microwave heating of materials. Finally stability analysis was done on a 1-D model of microwave heating and the equations for the perturbations were obtained.
15

Applications of the microwave-enhanced advanced oxidation process

Chan, Winnie Weng I 11 1900 (has links)
Municipal wastewater treatment using biological nutrient removal generates large amounts of waste sludge. An effort is made to solubilize nutrients from sludge and reuse them in subsequent processes. The microwave-enhanced advanced oxidation (MW/H₂O₂-AOP) process using hydrogen peroxide as the oxidant was applied to the treatment of different organic slurries including wasted sludge, blood meal, and fish silage. The factors controlling phosphates, ammonia, and COD release into solution included inorganic acid addition, hydrogen peroxide dosage, treatment times and temperatures. Higher dosages and treatment temperatures yielded better solubilization of phosphates and ammonia. It was found that approximately all of the COD was solubilized at a treatment temperature of 80°C. Volatile fatty acid (VFA) concentrations were also found to have increased with the amount of inorganic acid added into treatment. Up to 25% of soluble COD was composed of acetic acid. Higher irradiation levels tended to be more effective in the solubilization of nutrients. In terms of trends of particle size distribution, detectable particles increased in size in acidic conditions, with the largest fraction of larger particles in a given sample being the treatment with highest irradiation power. In neutral condition treatments, the higher the irradiation power provided to the samples, the more spread out the particle sizes range. In alkaline condition treatments, an increase in smaller particles were found after treatment; higher power irradiation yielded significantly higher numbers of smaller particles. This study provided an insight into the athermal effects of theMW/H₂O₂-AOP. Blood meal solubilization for the purpose of its application as an organic feritilizer was investigated using theMW/H₂O₂-AOP. It was found that over the treatment temperature range of 60 to l20C, solids particle reduction, ammonia and orthophosphate production were achieved. Maximum solubility of chemical oxygen demand (COD) occurred at 80°C. Without the addition of acid, soluble COD decreased due to protein denaturation and coagulation out of the solution. Fish silage is also a valuable fertilizer for organic greenhouse hydroponics operations, but a pretreatment step is required. It was found that up to 26% of total Kjeldahl nitrogen could be released as ammonia with 6% hydrogen peroxide dosage at 170°C. An increase of nitrate/nitrite concentration was observed with higher hydrogen peroxide dosage and higher microwave temperature.
16

Phase manipulation and its applications in microwave circuits /

Wong, Ka Wai. January 2009 (has links) (PDF)
Thesis (M.Phil.)--City University of Hong Kong, 2009. / "Submitted to Department of Electronic Engineering in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references.
17

Unobstrusive determination of hotspots as a function of spatial area inside a microwave

Sleiter, Nathan J. January 2003 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2003. / Includes bibliographical references.
18

Experimental and theoretical investigations of microwave heating

Kota, Bhagat Chandra 30 September 2004 (has links)
In this work we proposed the governing equations for describing the microwave heating process where the complex interactions between the thermo-mechanical and electromagnetic fields are taken into account. Starting point are the general balance laws of mechanics and electrodynamics. Transient and spatial temperature profiles of liquids (water and corn solution) inside a cylindrical container during microwave heating at 2450 MHz were measured. Transient temperature rise at a given location was almost linear. The slowest heating region was at the container bottom due to small energy penetration through the bottom. Numerical simulations were carried out for microwave heating of 2D cylinders of pure water with internal convection in the liquid regions. The results are found to be consistent with those of the experiments. A generalized theoretical model was formulated for the process of microwave heating of materials. Finally stability analysis was done on a 1-D model of microwave heating and the equations for the perturbations were obtained.
19

Applications of the microwave-enhanced advanced oxidation process

Chan, Winnie Weng I 11 1900 (has links)
Municipal wastewater treatment using biological nutrient removal generates large amounts of waste sludge. An effort is made to solubilize nutrients from sludge and reuse them in subsequent processes. The microwave-enhanced advanced oxidation (MW/H₂O₂-AOP) process using hydrogen peroxide as the oxidant was applied to the treatment of different organic slurries including wasted sludge, blood meal, and fish silage. The factors controlling phosphates, ammonia, and COD release into solution included inorganic acid addition, hydrogen peroxide dosage, treatment times and temperatures. Higher dosages and treatment temperatures yielded better solubilization of phosphates and ammonia. It was found that approximately all of the COD was solubilized at a treatment temperature of 80°C. Volatile fatty acid (VFA) concentrations were also found to have increased with the amount of inorganic acid added into treatment. Up to 25% of soluble COD was composed of acetic acid. Higher irradiation levels tended to be more effective in the solubilization of nutrients. In terms of trends of particle size distribution, detectable particles increased in size in acidic conditions, with the largest fraction of larger particles in a given sample being the treatment with highest irradiation power. In neutral condition treatments, the higher the irradiation power provided to the samples, the more spread out the particle sizes range. In alkaline condition treatments, an increase in smaller particles were found after treatment; higher power irradiation yielded significantly higher numbers of smaller particles. This study provided an insight into the athermal effects of theMW/H₂O₂-AOP. Blood meal solubilization for the purpose of its application as an organic feritilizer was investigated using theMW/H₂O₂-AOP. It was found that over the treatment temperature range of 60 to l20C, solids particle reduction, ammonia and orthophosphate production were achieved. Maximum solubility of chemical oxygen demand (COD) occurred at 80°C. Without the addition of acid, soluble COD decreased due to protein denaturation and coagulation out of the solution. Fish silage is also a valuable fertilizer for organic greenhouse hydroponics operations, but a pretreatment step is required. It was found that up to 26% of total Kjeldahl nitrogen could be released as ammonia with 6% hydrogen peroxide dosage at 170°C. An increase of nitrate/nitrite concentration was observed with higher hydrogen peroxide dosage and higher microwave temperature.
20

Synthesis and Design of Novel Dual-Mode Microwave Filters

Wahby, Mahmoud 08 April 2011 (has links)
This thesis describes the synthesis and design of two novel dual-mode microwave waveguide filter structures. The mode degeneracy is fundamental to this design technique. The first design introduces a structurally symmetric dual-mode cavity pseudo-elliptic band-pass filter, which has been implemented by only asymmetric structures so far. It is also used to shed light on the concepts of positive and negative coupling in dual-mode filters. A novel iris coupling structure is investigated allowing negative coupling coefficients required for certain polarizations of modes in dual- mode rectangular cavities. A 4th order dual-mode band-pass filter is designed at 11 GHz with a bandwidth of 200 MHz, an in-band return loss of 20dB and two transmission zeros at normalized frequencies of ±1.6. The filter makes use of the negative coupling property of the iris for inter-resonance coupling of the modes of horizontal orientation inside the cavity. The desired performance of the filter was achieved by the initial design without any optimization. The second design is especially convenient when temperature compensation is of prime concern. A direct design technique is developed and demonstrated with computer simulation and measurement in circular waveguide technology on a 4th order filter with a bandwidth of 50 MHz at 11 GHz, an in-band return loss of 20 dB and two normalized transmission zeros at ±1.5. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2011-04-08 12:41:14.602

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