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.
Results
Showing 1 to 20 of 552 for “"wideband"”.
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Wideband reconfigurable antennas
… in this thesis concerns the combining of wideband and reconfigurable narrow band functionality into a single antenna. This concept may be useful in reducing size and to give flexibility to a wireless terminal to operate in several different modes. The approach also offers additional …
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Wideband active antenna cancellation
… system where the transmitted signal is creating wideband interference of the receiver. To resolve this interference problem, the isolation between the transmit antenna and the receive antenna must be increased. This thesis analyzes and discusses various strategies for antenna isolation and …
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Ultra-wideband digital baseband
The FCC approved the use of Ultra-wideband signals for communication purposes in February 2002 in the band from 3.1GHz to 10.6GHz, effectively opening 7.5GHz of free unlicensed bandwidth. There are two main constraints for the use of this band: a maximum EIRP spectral density of -41.3dBm/MHz and a …
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Design of Ultra-wideband Reflectors
… bandwidth. This thesis investigates how ultra-wideband reflectors can be designed using novel approaches going beyond the conventional approaches listed above. Specifically, we investigate two new methods to design reflectarrays. In the first method, the reflector is designed as a …
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On sounding in wideband channels
(cont.) This approach provides us with a cohesive framework to consider the relative costs and benefits of allotting energy for sounding versus transmission, and for repeated sounding of a single channel versus sounding of various different channels. In particular, we are able to give both an upper …
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Fundamental limits of wideband localization
… we investigate the localization performance of wideband networks and proposed a performance measure called the squared position error bound (SPEB) to characterize the localization accuracy. We derive the SPEB succinctly by applying the notion of equivalent Fisher information (EFI). The EFI …
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Development of wideband phased array antenna
Wideband communication system covering the range from 4 to 8 GHz requires compact antenna to provide desirable characteristic over whole operating band. This project consists of two designs; first design is presented with optimum geometry of an ultra wideband circular patch antenna. To achieve an …
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Ultra-Wideband Transceiver Design And Optimization
… This work explores the use of the 802.15 ulta wideband (UWB) standard for designing a radio to operate in the a wireless sensor network in the BAN. The specific application targeted is a hearing aid. However, the design in this work is capable of working in a low power low range application …
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PORTABLE WIDEBAND MICROSEISMIC DATA ACQUISITION SYSTEM
… focus of this research was to develop a portable wideband data acquisition system that can be used to acquire data from newly developed transducers and compare the recorded waveforms with that obtained from transducers already in use. The data acquistion system developed in this research has an …
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Wideband Channel Characterization for MIMO Scenario
… the Saleh Valenzuela with Angle (SVA) model for wideband MIMO communication models. While recent wideband MIMO measurements have been obtained by switching a single transmit/receive pair over all possible antenna pair combinations, a simultaneous probing system is superior because of the time …
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Ultra-Wideband Microwave Imaging Radar System
A novel way to reduce the CPU run time and memory requirement of the nonlinear inverse scattering algorithms is also proposed in this study. We propose a code-division multiplexing scheme for the nonlinear inverse scattering algorithms to reduce the computational complexity by a factor proportional …
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Ultrasonic transducers for wideband attenuation measurements
… the ultrasonic transducers exhibit efficient wideband characteristics. Piezoceramic transducers vibrating in thickness-mode are the most suitable to generate ultrasound at these frequencies. However, their high acoustic impedances relative to their liquid loads make them inherently narrowband …
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Antenna design for ultra wideband radio
… Communications Commission (FCC) for Ultra Wideband (UWB) radio applications has presented a myriad of exciting opportunities and challenges for design in the communications arena, including antenna design. Ultra Wideband Radio requires operating bandwidths up to greater than 100% of the …
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Synthesis of Ultra-Wideband Array Antennas
Acquisition of ultra-wideband signals by means of array antennas requires essentially frequency-independent radiation characteristics over the entire bandwidth of the signal in order to avoid distortions. Factors contributing to bandwidth limitation of arrays include array factor, radiation …
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Wideband rotary transformer for VHF use
The theory of static wideband transformers has been applied to the design of a VHF rotary coupler that has a bandwidth ratio of 1000:1, and that requires no physical contact between the stator and rotor. A combination of balanced and unbalanced transmission line theory has been used to predict the …
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Transceiver Design for Ultra-Wideband Communications
Despite the fact ultra-wideband (UWB) technology has been around for over 30 years, there is a newfound excitement about its potential for communications. With the advantageous qualities of multipath immunity and low power spectral density, researchers are examining fundamental questions about UWB …
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Wideband characterization of thick film inductors
This work presents a method based on time domain techniques to characterize and model thick film inductor structures. The method is a time domain reflection (TOR) measurement which measures the input port's reflection transfer function of the component under test. The reflection from a short …
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Characterization of Wideband All-Fiber Waveplates
… polarization transformation behavior and the wideband nature of the Huang fiber. We analyzed the dependence of the polarization transformation by this device on various structural parameters and showed that while the fiber has loose tolerances with respect to the fiber length and the spin …
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Ultra-Wideband Antenna Characterization and Modeling
A new methodology is presented for characterizing an antenna system both in the time and frequency domain with one set of parameters using a singularity expansion method representation. A minimal set of parameter modeling antenna systems using the Matrix-Pencil method has been demonstrated. It has …
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Characterization of Ultra Wideband Communication Channels
Ultra-wideband (UWB) communication has been the subject of extensive research in recent years due to its unique capabilities and potential applications, particularly in short-range multiple access wireless communications. However, many important aspects of UWB-based communication systems have not …
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