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Full-Text Articles in Engineering
Analysis, Design And Efficiency Optimization Of Power Converters For Renewable Energy Applications, Xi Chen
Analysis, Design And Efficiency Optimization Of Power Converters For Renewable Energy Applications, Xi Chen
Electronic Theses and Dissertations
DC-DC power converters are widely used in renewable energy-based power generation systems due to the constant demand of high-power density and high-power conversion efficiency. DC-DC converters can be classified into non-isolated and isolated topologies. For non-isolated topologies, they are typically derived from buck, boost, buck-boost or forth order (such as Cuk, Sepic and Zeta) converters and they usually have relatively higher conversion efficiency than isolated topologies. However, with the applications where the isolation is required, either these topologies should be modified, or alternative topologies are needed. Among various isolated DC-DC converters, the LLC resonant converter is an attractive selection due …
Reconfigurable Reflectarray Antennas With Bandwidth Enhancement For High Gain, Beam-Steering Applications, Michael Trampler
Reconfigurable Reflectarray Antennas With Bandwidth Enhancement For High Gain, Beam-Steering Applications, Michael Trampler
Electronic Theses and Dissertations
Reconfigurable reflectarrays are a class of antennas that combine the advantages of traditional parabolic antennas and phased array antennas. Chapter 1 discusses the basic operational theory of reflectarrays and their design. A review of previous research and the current status is also presented. Furthermore the inherent advantages and disadvantages of the reflectarray topography are presented. In chapter 2, a BST-integrated reflectarray operating at Ka band is presented. Due to the monolithic integration of the tuning element, this design is then extended to V band where a novel interdigital gap configuration is utilized. Finally to overcome loss and phase limitations of …
Frequency-Reconfigurable Microstrip Patch And Cavity-Backed Slot Espars, Wei Ouyang
Frequency-Reconfigurable Microstrip Patch And Cavity-Backed Slot Espars, Wei Ouyang
Electronic Theses and Dissertations
Wireless communication systems have rapidly evolved over the past decade which has led to an explosion of mobile data traffic. Since more and more wireless devices and sensors are being connected, the transition from the current 4G/LTE mobile network to 5G is expected to happen within the next decade. In order to improve signal-to-noise ratio (SNR), system capacity, and link budget, beam steerable antenna arrays are desirable due to their advantage in spatial selectivity and high directivity. Electronically steerable parasitic array radiator (ESPAR) that can achieve low-cost continuously beamsteering using varactor diodes have attracted a lot of attention. This dissertation …
Programmable Low Loss Orthogonal Frequency Coded Surface Acoustic Wave Correlator Filters, Marshall Smith
Programmable Low Loss Orthogonal Frequency Coded Surface Acoustic Wave Correlator Filters, Marshall Smith
Electronic Theses and Dissertations
Simultaneous Transmit and Receive (STAR) communication is being developed as a means of improving spectral efficiency in wireless communication systems. If the obstacle of self-interference can be sufficiently overcome, it is possible to double the spectral efficiency of an equivalent time or frequency division duplexed system. Spread spectrum techniques can reduce self-interference by using orthogonal or pseudo-orthogonal codes to encode the transmit signal and decode the receive signal. Hardware correlator filters are developed for use with STAR radio systems using orthogonal frequency coded (OFC) surface acoustic wave (SAW) devices. OFC is a type of spread spectrum communication that can be …
Semiconductor Device Modeling, Simulation, And Failure Prediction For Electrostatic Discharge Conditions, Hang Li
Electronic Theses and Dissertations
Electrostatic Discharge (ESD) caused failures are major reliability issues in IC industry. Device modeling for ESD conditions is necessary to evaluate ESD robustness in simulation. Although SPICE model is accurate and efficient for circuit simulations in most cases, devices under ESD conditions operate in abnormal status. SPICE model cannot cover the device operating region beyond normal operation. Thermal failure is one of the main reasons to cause device failure under ESD conditions. A compact model is developed to predict thermal failure with circuit simulators. Instead of considering the detailed failure mechanisms, a failure temperature is introduced to indicate device failure. …
Sparse Signal Recovery Under Sensing And Physical Hardware Constraints, Davood Mardaninajafabadi
Sparse Signal Recovery Under Sensing And Physical Hardware Constraints, Davood Mardaninajafabadi
Electronic Theses and Dissertations
This dissertation focuses on information recovery under two general types of sensing constraints and hardware limitations that arise in practical data acquisition systems. We study the effects of these practical limitations in the context of signal recovery problems from interferometric measurements such as for optical mode analysis. The first constraint stems from the limited number of degrees of freedom of an information gathering system, which gives rise to highly constrained sensing structures. In contrast to prior work on compressive signal recovery which relies for the most part on introducing additional hardware components to emulate randomization, we establish performance guarantees for …