198 research outputs found

    Inductance Simulators and Their Application to the 4th Order Elliptic Lowpass Ladder Filter Using CMOS VD-DIBAs

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    This paper presents inductance simulators using the voltage differencing differential input buffered amplifier (VD-DIBA) as an active building block. Three types of inductance simulators, including floating lossless inductance, series inductance-resistance, and parallel inductance-resistance simulators, are proposed, in addition to their application to the 4th order elliptic lowpass ladder filter. The simple design procedures of these inductance simulators using a circuit block diagram are also given. The proposed inductance simulators employ two VD-DIBAs and two passive elements. The complementary metal oxide semiconductor (CMOS) VD-DIBA used in this design utilizes the multiple-input metal oxide semiconductor (MOS) transistor technique in order to achieve a compact and simple structure with a minimum count of transistors. Thanks to this technique, the VD-DIBA offers high performances compared to the other CMOS structures presented in the literature. The CMOS VD-DIBAs and their applications are designed and simulated in the Cadence environment using a 0.18 mu m CMOS process from Taiwan semiconductor manufacturing company (TSMC). Using a supply voltage of +/- 0.9 V, the linear operation of VD-DIBA is obtained over a differential input range of -0.5 V to 0.5 V. The lowpass (LP) ladder filter realized with the proposed inductance simulators shows a dynamic range (DR) of 80 dB for a total harmonic distortion (THD) of 2% at 1 kHz and a 1.8 V peak-to-peak output. In addition, the experimental results of the floating inductance simulators and their applications are obtained by using VD-DIBA constructed from the available commercial components LM13700 and AD830. The simulation results are in agreement with the experimental ones, confirming the advantages of the inductance simulators and their application

    System and Circuit Design Aspects for CMOS Wireless Handset Receivers

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    Analog Implementation of Fractional-Order Elements and Their Applications

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    With advancements in the theory of fractional calculus and also with widespread engineering application of fractional-order systems, analog implementation of fractional-order integrators and differentiators have received considerable attention. This is due to the fact that this powerful mathematical tool allows us to describe and model a real-world phenomenon more accurately than via classical “integer” methods. Moreover, their additional degree of freedom allows researchers to design accurate and more robust systems that would be impractical or impossible to implement with conventional capacitors. Throughout this thesis, a wide range of problems associated with analog circuit design of fractional-order systems are covered: passive component optimization of resistive-capacitive and resistive-inductive type fractional-order elements, realization of active fractional-order capacitors (FOCs), analog implementation of fractional-order integrators, robust fractional-order proportional-integral control design, investigation of different materials for FOC fabrication having ultra-wide frequency band, low phase error, possible low- and high-frequency realization of fractional-order oscillators in analog domain, mathematical and experimental study of solid-state FOCs in series-, parallel- and interconnected circuit networks. Consequently, the proposed approaches in this thesis are important considerations in beyond the future studies of fractional dynamic systems

    Integrated Building Cells for a Simple Modular Design of Electronic Circuits with Reduced External Complexity: Performance, Active Element Assembly, and an Application Example

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    This paper introduces new integrated analog cells fabricated in a C035 I3T25 0.35-m ON Semiconductor process suitable for a modular design of advanced active elements with multiple terminals and controllable features. We developed and realized five analog cells on a single integrated circuit (IC), namely a voltage differencing differential buffer, a voltage multiplier with current output in full complementary metal–oxide–semiconductor (CMOS) form, a voltage multiplier with current output with a bipolar core, a current-controlled current conveyor of the second generation with four current outputs, and a single-input and single-output adjustable current amplifier. These cells (sub-blocks of the manufactured IC device), designed to operate in a bandwidth of up to tens of MHz, can be used as a construction set for building a variety of advanced active elements, offering up to four independently adjustable internal parameters. The performances of all individual cells were verified by extensive laboratory measurements, and the obtained results were compared to simulations in the Cadence IC6 tool. The definition and assembly of a newly specified advanced active element, namely a current-controlled voltage differencing current conveyor transconductance amplifier (CC-VDCCTA), is shown as an example of modular interconnection of the selected cells. This device was implemented in a newly synthesized topology of an electronically linearly tunable quadrature oscillator. Features of this active element were verified by simulations and experimental measurements

    Design and Control of Power Converters for High Power-Quality Interface with Utility and Aviation Grids

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    Power electronics as a subject integrating power devices, electric and electronic circuits, control, and thermal and mechanic design, requires not only knowledge and engineering insight for each subarea, but also understanding of interface issues when incorporating these different areas into high performance converter design.Addressing these fundamental questions, the dissertation studies design and control issues in three types of power converters applied in low-frequency high-power transmission, medium-frequency converter emulated grid, and high-frequency high-density aviation grid, respectively, with the focus on discovering, understanding, and mitigating interface issues to improve power quality and converter performance, and to reduce the noise emission.For hybrid ac/dc power transmission,• Analyze the interface transformer saturation issue between ac and dc power flow under line unbalances.• Proposed both passive transformer design and active hybrid-line-impedance-conditioner to suppress this issue.For transmission line emulator,• Propose general transmission line emulation schemes with extension capability.• Analyze and actively suppress the effects of sensing/sampling bias and PWM ripple on emulation considering interfaced grid impedance.• Analyze the stability issue caused by interaction of the emulator and its interfaced impedance. A criterion that determines the stability and impedance boundary of the emulator is proposed.For aircraft battery charger,• Investigate architectures for dual-input and dual-output battery charger, and a three-level integrated topology using GaN devices is proposed to achieve high density.• Identify and analyze the mechanisms and impacts of high switching frequency, di/dt, dv/dt on sensing and power quality control; mitigate solutions are proposed.• Model and compensate the distortion due to charging transition of device junction capacitances in three-level converters.• Find the previously overlooked device junction capacitance of the nonactive devices in three-level converters, and analyze the impacts on switching loss, device stress, and current distortion. A loss calculation method is proposed using the data from the conventional double pulse tester.• Establish fundamental knowledge on performance degradation of EMI filters. The impacts and mechanisms of both inductive and capacitive coupling on different filter structures are understood. Characterization methodology including measuring, modeling, and prediction of filter insertion loss is proposed. Mitigation solutions are proposed to reduce inter-component coupling and self-parasitics

    Inkjet-printed sensors and via-enabled structures for low-cost autonomous wireless platforms

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    Fundamental research to implement the printed autonomous wireless sensor platform is studied in three aspects: fabrication method, material selection, and novel applications for autonomous sensing/communication. Additive fabrication processes, such as inkjet printing technology and electroless electroplating, are discussed and the additively created metal layers are characterized. Fundamentals for material characterization utilizing resonators are presented and electrical properties of flexible low-cost substrates like synthetic Teslin paper and Poly(methyl methacrylate) (PMMA) are characterized. Widely used flexible substrates for printing, such as Liquid Crystal Polymer (LCP) and Kapton (polyimide), are summarized and tabulated as well. Novel antenna-based applications for efficient and autonomous operation of wireless sensor system, such as an antenna on Artificial Magnetic Conductor (AMC) for wearable applications, an active beacon oscillator for Wireless Power Transfer (WPT), and a multiband RF energy harvester, are designed and their performances are experimentally verified. The printed RFID-enabled sensor topologies with/without RFID chip are discussed as a new sensor platform for autonomous wireless operation. Fully inkjet-printed via topology for system miniaturization and integration is proposed for the first time. Challenges, circuit modeling and experimental data are presented. Future and remaining work to implement the novel low-cost autonomous wireless sensor platform are also discussed.Ph.D

    Miniaturized Microwave Devices and Antennas for Wearable, Implantable and Wireless Applications

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    This thesis presents a number of microwave devices and antennas that maintain high operational efficiency and are compact in size at the same time. One goal of this thesis is to address several miniaturization challenges of antennas and microwave components by using the theoretical principles of metamaterials, Metasurface coupling resonators and stacked radiators, in combination with the elementary antenna and transmission line theory. While innovating novel solutions, standards and specifications of next generation wireless and bio-medical applications were considered to ensure advancement in the respective scientific fields. Compact reconfigurable phase-shifter and a microwave cross-over based on negative-refractive-index transmission-line (NRI-TL) materialist unit cells is presented. A Metasurface based wearable sensor architecture is proposed, containing an electromagnetic band-gap (EBG) structure backed monopole antenna for off-body communication and a fork shaped antenna for efficient radiation towards the human body. A fully parametrized solution for an implantable antenna is proposed using metallic coated stacked substrate layers. Challenges and possible solutions for off-body, on-body, through-body and across-body communication have been investigated with an aid of computationally extensive simulations and experimental verification. Next, miniaturization and implementation of a UWB antenna along with an analytical model to predict the resonance is presented. Lastly, several miniaturized rectifiers designed specifically for efficient wireless power transfer are proposed, experimentally verified, and discussed. The study answered several research questions of applied electromagnetic in the field of bio-medicine and wireless communication.Comment: A thesis submitted for the degree of Ph

    Integrated RF oscillators and LO signal generation circuits

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    This thesis deals with fully integrated LC oscillators and local oscillator (LO) signal generation circuits. In communication systems a good-quality LO signal for up- and down-conversion in transmitters is needed. The LO signal needs to span the required frequency range and have good frequency stability and low phase noise. Furthermore, most modern systems require accurate quadrature (IQ) LO signals. This thesis tackles these challenges by presenting a detailed study of LC oscillators, monolithic elements for good-quality LC resonators, and circuits for IQ-signal generation and for frequency conversion, as well as many experimental circuits. Monolithic coils and variable capacitors are essential, and this thesis deals with good structures of these devices and their proper modeling. As experimental test devices, over forty monolithic inductors and thirty varactors have been implemented, measured and modeled. Actively synthesized reactive elements were studied as replacements for these passive devices. At first glance these circuits show promising characteristics, but closer noise and nonlinearity analysis reveals that these circuits suffer from high noise levels and a small dynamic range. Nine circuit implementations with various actively synthesized variable capacitors were done. Quadrature signal generation can be performed with three different methods, and these are analyzed in the thesis. Frequency conversion circuits are used for alleviating coupling problems or to expand the number of frequency bands covered. The thesis includes an analysis of single-sideband mixing, frequency dividers, and frequency multipliers, which are used to perform the four basic arithmetical operations for the frequency tone. Two design cases are presented. The first one is a single-sideband mixing method for the generation of WiMedia UWB LO-signals, and the second one is a frequency conversion unit for a digital period synthesizer. The last part of the thesis presents five research projects. In the first one a temperature-compensated GaAs MESFET VCO was developed. The second one deals with circuit and device development for an experimental-level BiCMOS process. A cable-modem RF tuner IC using a SiGe process was developed in the third project, and a CMOS flip-chip VCO module in the fourth one. Finally, two frequency synthesizers for UWB radios are presented
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