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 20 for “"Tunable filters"”.
-
Investigation of Narrowband Acousto-Optic Tunable Filters for Semiconductor Laser Tuning
Wavelength tunable sources find applications in areas of laser surgery, optical coherence tomography, material processing, and differential absorption light detection and ranging. Acousto-optic tunable filters (AOTFs) are wavelength selective devices which allow for better stability than mechanical …
-
Reconfigurable RF front end: A mixer-first architecture and tunable filters
… a mixer-first receiver system and an on-chip tunable bandpass filter, are reviewed and verified. For the mixer-first receiver, a pure passive mixer called distributedly modulated capacitor (DMC) is introduced and analyzed, then simulation in ADS is reported, the results of which prove the …
-
A study of novel mid-infrared optical devices: Wave plates and tunable filters
… a way to make the filter structure actively tunable.
-
Tunable Filters and Interference Rejection System for Interferer Suppression at RF and Microwave Bands
… integration of high selectivity RF band-pass filters (BPF), or band-stop filters (BSF) is challenging because of limited quality factor (Q) of passive components in integrated circuit (IC) technology [1]. This proposed research achieves the followings: 1. Developing, and demonstrating …
-
Theory and design of mixed lumped-distributed cross-coupled filters with applications to linear phase shifter and tunable filters
… this performance, various types of combline filters are suggested. Various simulation tools (commercial linear circuit and E-M simulators), as well as the developed pole-zero locator program, were used to design a new class of cross-coupled networks. In particular, the polezero locator …
-
High-Power Microwave/ Radio-Frequency Components, Circuits, and Subsystems for Next-Generation Wireless Radio Front-Ends
… integration with high-quality-factor (high-Q) tunable filters, and relevant investigations on the reliabilities of these tunable devices. It can be basically divided into three major parts:</p> <p>1.Broadband High-Efficiency Power Amplifiers. Obtaining high PA efficiency over a wide bandwidth …
-
Synthesis, design, and fabrication techniques for reconfigurable microwave and millimeter-wave filters
… In order to realize reconfigurable receivers, tunable RF front-end components are needed. This dissertation focuses on the theory, design, and implementation of reconfigurable microwave and millimeter-wave filters for use in such receivers.</p> <p>First, a theoretical framework is developed for …
-
Compensation technique for nonlinear distortion in RF circuits for multi-standard wireless systems
… such as power amplifiers, reconfigurable and tunable filters and modulators, these interfering signals produce nonlinear distortion products which can deform the output signal considerably. Hence it becomes necessary to block these interfering signals using special components. The main …
-
Photonic RF signal processors
… namely: • Interference mitigation and high Q tunable filters. • Arbitrary filter transfer function generation. The thesis begins with a review on several state-of-the-art architectures of in-fiber RF signal processing and related key optical technologies. The unique capabilities offered by …
-
Design, fabrication, and characterization of a lithium niobate optomechanical photodetector based on released whispering-gallery-mode microdisk resonators
… and devices, electro-optical modulators and tunable filters, and other high-speed and low-loss photonic devices. In this work, an opto-electro-mechanical device for detecting light power is developed on a Lithium Niobate platform using a combination of Whispering-Gallery-Mode (WGM) micro-disk …
-
Linearity improvement technique for CMOS continuous-time filters
… implementation of low-distortion continuous-time filters in complementary metal-oxide-semiconductor (CMOS) technology. This work is motivated by the fact that to date, most of the techniques in continuous-time, electronically tunable filters perform quite poorly in linearity. The proposed …
-
Study of Multiple ASE-Noise Effects and A Filtering Solution For Soliton Propagation Through Optical Fibers
… it is determined that acousto-optic tunable filters (AOTF)s are capable of providing the narrowband filtering capabilities required for the design as well as the necessary frequency shifting aspects of a modulator. To this end, a variety of materials applicable for use in …
-
Miniaturised bandpass filters for wireless communications
… development and realization of RF and microwave filters, which have not only sustained but fuelled microwave filter research over the many years. These developments have encouraged new solutions and techniques for the realization of compact, low loss, highly selective RF and microwave bandpass …
-
The design and realisation of electronically tunable dielectric resonator microstrip filters
… demand for highly selective and frequency agile filters with fast tuning rates. At microwave frequencies above 2GHz, filters that combine both tuning speed and high selectivity are difficult to realise. Unloaded Q values in the range of 1000 are required for reasonable selectivity. At present, …
-
Integrated Tunable LC Higher-Order Microwave Filters for Interference Mitigation
… bottleneck for SDRs 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, …
-
Silicon-based tunable optical filters
… characterization of a new class of silicon-based tunable optical filters. For this purpose a Fabry-Perot structure was chosen and implemented as a thin-film interference filter. The filter layers were configured as a self-supporting square membrane with side lengths of a few hundred microns. The …
-
Filter Design for Interference Cancellation for Wide and Narrow Band RF Systems
… there has been tremendous effort to design RF tunable filters, there is still lack of designs with frequency and bandwidth software-tuning capability at frequencies above 4 GHz. This prevents the implementation of Software Defined Radios (SDR) where software tuning is a critical part in …
-
Contribución al estudio y optimización de dispositivos basados en holografía dinámica para su uso en redes ópticas pasivas multiplexadas en longitud de onda Wdm-Pon
… as transmitters, receivers, de/multiplexers, filters, etc. It is in this context where the use of holographic devices, WDM tunables, takes different applications as network elements like filters, demultiplexers, wavelength routers, add/drop optical multiplexers (OADMs) and optical switching …
-
Filter Synthesis and Design Techniques for Highly Adaptable Systems
… and switched banks of static, wide bandwidth filters before the digitization process. These components limit the ability of SDR/CR systems to operate in environments with high levels of interference and are therefore a bottleneck in the path to achieving optimal adaptation of wireless systems. …
-
Applications of Non-linearities in RF MEMS Switches and Resonators
… etc.) and micromechanical resonators (used in tunable filters, oscillators, reference clocks etc.). MEMS technology also has the potential to be directly integrated into CMOS (Complementary metal-oxide semiconductor) ICs (Integrated Circuits) leading to further potential reductions of cost and …