6 research outputs found

    Advances in Integrated Circuit Design and Implementation for New Generation of Wireless Transceivers

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    User’s everyday outgrowing demand for high-data and high performance mobile devices pushes industry and researchers into more sophisticated systems to fulfill those expectations. Besides new modulation techniques and new system designs, significant improvement is required in the transceiver building blocks to handle higher data rates with reasonable power efficiency. In this research the challenges and solution to improve the performance of wireless communication transceivers is addressed. The building block that determines the efficiency and battery life of the entire mobile handset is the power amplifier. Modulations with large peak to average power ratio severely degrade efficiency in the conventional fixed-biased power amplifiers (PAs). To address this challenge, a novel PA is proposed with an adaptive load for the PA to improve efficiency. A nonlinearity cancellation technique is also proposed to improve linearity of the PA to satisfy the EVM and ACLR specifications. Ultra wide-band (UWB) systems are attractive due to their ability for high data rate, and low power consumption. In spite of the limitation assigned by the FCC, the coexistence of UWB and NB systems are still an unsolved challenge. One of the systems that is majorly affected by the UWB signal, is the 802.11a system (5 GHz Wi-Fi). A new analog solution is proposed to minimize the interference level caused by the impulse Radio UWB transmitter to nearby narrowband receivers. An efficient 400 Mpulse/s IR-UWB transmitter is implemented that generates an analog UWB pulse with in-band notch that covers the majority of the UWB spectrum. The challenge in receiver (RX) design is the over increasing out of blockers in applications such as cognitive and software defined radios, which are required to tolerate stronger out-of-band (OB) blockers. A novel RX is proposed with a shunt N-path high-Q filter at the LNA input to attenuate OB-blockers. To further improve the linearity, a novel baseband blocker filtering techniques is proposed. A new TIA has been designed to maintain the good linearity performance for blockers at large frequency offsets. As a result, a +22 dBm IIP3 with 3.5 dB NF is achieved. Another challenge in the RX design is the tough NF and linearity requirements for high performance systems such as carrier aggregation. To improve the NF, an extra gain stage is added after the LNA. An N-path high-Q band-pass filter is employed at the LNA output together with baseband blocker filtering technique to attenuate out-of-band blockers and improve the linearity. A noise-cancellation technique based on the frequency translation has been employed to improve the NF. As a result, a 1.8dB NF with +5 dBm IIP3 is achieved. In addition, a new approach has been proposed to reject out of band blockers in carrier aggregation scenarios. The proposed solution also provides carrier to carrier isolation compared to typical solution for carrier aggregation

    Continuous-time low-pass filters for integrated wideband radio receivers

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    This thesis concentrates on the design and implementation of analog baseband continuous-time low-pass filters for integrated wideband radio receivers. A total of five experimental analog baseband low-pass filter circuits were designed and implemented as a part of five single-chip radio receivers in this work. After the motivation for the research work presented in this thesis has been introduced, an overview of analog baseband filters in radio receivers is given first. In addition, a review of the three receiver architectures and the three wireless applications that are adopted in the experimental work of this thesis is presented. The relationship between the integrator non-idealities and integrator Q-factor, as well as the effect of the integrator Q-factor on the filter frequency response, are thoroughly studied on the basis of a literature review. The theoretical study that is provided is essential for the gm-C filter synthesis with non-ideal lossy integrators that is presented after the introduction of different techniques to realize integrator-based continuous-time low-pass filters. The filter design approach proposed for gm-C filters is original work and one of the main points in this thesis, in addition to the experimental IC implementations. Two evolution versions of fourth-order 10-MHz opamp-RC low-pass filters designed and implemented for two multicarrier WCDMA base-station receivers in a 0.25-µm SiGe BiCMOS technology are presented, along with the experimental results of both the low-pass filters and the corresponding radio receivers. The circuit techniques that were used in the three gm-C filter implementations of this work are described and a common-mode induced even-order distortion in a pseudo-differential filter is analyzed. Two evolution versions of fifth-order 240-MHz gm-C low-pass filters that were designed and implemented for two single-chip WiMedia UWB direct-conversion receivers in a standard 0.13-µm and 65-nm CMOS technology, respectively, are presented, along with the experimental results of both the low-pass filters and the second receiver version. The second UWB filter design was also embedded with an ADC into the baseband of a 60-GHz 65-nm CMOS radio receiver. In addition, a third-order 1-GHz gm-C low-pass filter was designed, rather as a test structure, for the same receiver. The experimental results of the receiver and the third gm-C filter implementation are presented

    High Performance RF and Basdband Analog-to-Digital Interface for Multi-standard/Wideband Applications

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    The prevalence of wireless standards and the introduction of dynamic standards/applications, such as software-defined radio, necessitate the next generation wireless devices that integrate multiple standards in a single chip-set to support a variety of services. To reduce the cost and area of such multi-standard handheld devices, reconfigurability is desirable, and the hardware should be shared/reused as much as possible. This research proposes several novel circuit topologies that can meet various specifications with minimum cost, which are suited for multi-standard applications. This doctoral study has two separate contributions: 1. The low noise amplifier (LNA) for the RF front-end; and 2. The analog-to-digital converter (ADC). The first part of this dissertation focuses on LNA noise reduction and linearization techniques where two novel LNAs are designed, taped out, and measured. The first LNA, implemented in TSMC (Taiwan Semiconductor Manufacturing Company) 0.35Cm CMOS (Complementary metal-oxide-semiconductor) process, strategically combined an inductor connected at the gate of the cascode transistor and the capacitive cross-coupling to reduce the noise and nonlinearity contributions of the cascode transistors. The proposed technique reduces LNA NF by 0.35 dB at 2.2 GHz and increases its IIP3 and voltage gain by 2.35 dBm and 2dB respectively, without a compromise on power consumption. The second LNA, implemented in UMC (United Microelectronics Corporation) 0.13Cm CMOS process, features a practical linearization technique for high-frequency wideband applications using an active nonlinear resistor, which obtains a robust linearity improvement over process and temperature variations. The proposed linearization method is experimentally demonstrated to improve the IIP3 by 3.5 to 9 dB over a 2.5–10 GHz frequency range. A comparison of measurement results with the prior published state-of-art Ultra-Wideband (UWB) LNAs shows that the proposed linearized UWB LNA achieves excellent linearity with much less power than previously published works. The second part of this dissertation developed a reconfigurable ADC for multistandard receiver and video processors. Typical ADCs are power optimized for only one operating speed, while a reconfigurable ADC can scale its power at different speeds, enabling minimal power consumption over a broad range of sampling rates. A novel ADC architecture is proposed for programming the sampling rate with constant biasing current and single clock. The ADC was designed and fabricated using UMC 90nm CMOS process and featured good power scalability and simplified system design. The programmable speed range covers all the video formats and most of the wireless communication standards, while achieving comparable Figure-of-Merit with customized ADCs at each performance node. Since bias current is kept constant, the reconfigurable ADC is more robust and reliable than the previous published works

    Smart Sensor Networks For Sensor-Neural Interface

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    One in every fifty Americans suffers from paralysis, and approximately 23% of paralysis cases are caused by spinal cord injury. To help the spinal cord injured gain functionality of their paralyzed or lost body parts, a sensor-neural-actuator system is commonly used. The system includes: 1) sensor nodes, 2) a central control unit, 3) the neural-computer interface and 4) actuators. This thesis focuses on a sensor-neural interface and presents the research related to circuits for the sensor-neural interface. In Chapter 2, three sensor designs are discussed, including a compressive sampling image sensor, an optical force sensor and a passive scattering force sensor. Chapter 3 discusses the design of the analog front-end circuit for the wireless sensor network system. A low-noise low-power analog front-end circuit in 0.5μm CMOS technology, a 12-bit 1MS/s successive approximation register (SAR) analog-to-digital converter (ADC) in 0.18μm CMOS process and a 6-bit asynchronous level-crossing ADC realized in 0.18μm CMOS process are presented. Chapter 4 shows the design of a low-power impulse-radio ultra-wide-band (IR-UWB) transceiver (TRx) that operates at a data rate of up to 10Mbps, with a power consumption of 4.9pJ/bit transmitted for the transmitter and 1.12nJ/bit received for the receiver. In Chapter 5, a wireless fully event-driven electrogoniometer is presented. The electrogoniometer is implemented using a pair of ultra-wide band (UWB) wireless smart sensor nodes interfacing with low power 3-axis accelerometers. The two smart sensor nodes are configured into a master node and a slave node, respectively. An experimental scenario data analysis shows higher than 90% reduction of the total data throughput using the proposed fully event-driven electrogoniometer to measure joint angle movements when compared with a synchronous Nyquist-rate sampling system. The main contribution of this thesis includes: 1) the sensor designs that emphasize power efficiency and data throughput efficiency; 2) the fully event-driven wireless sensor network system design that minimizes data throughput and optimizes power consumption

    A robust 2.4 GHz time-of-arrival based ranging system with sub-meter accuracy: feasibility study and realization of low power CMOS receiver

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    Draadloze sensornetwerken worden meer en meer aangewend om verschillende soorten informatie te verzamelen. De locatie, waar deze informatie verzameld is, is een belangerijke eigenschap en voor sommige toepassingen, zoals het volgen van personen of goederen, zelfs de meest belangrijke en mogelijkmakende factor. Om de positie van een sensor te bepalen, is een technologie nodig die de afstand tot een gekend referentiepunt schat. Door verschillende afstandsmetingen te combineren, is het mogelijk de absolute locatie van de node te berekenen

    Abstracts on Radio Direction Finding (1899 - 1995)

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    The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion
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