173 research outputs found

    Millimeter-wave Communication and Radar Sensing — Opportunities, Challenges, and Solutions

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    With the development of communication and radar sensing technology, people are able to seek for a more convenient life and better experiences. The fifth generation (5G) mobile network provides high speed communication and internet services with a data rate up to several gigabit per second (Gbps). In addition, 5G offers great opportunities of emerging applications, for example, manufacture automation with the help of precise wireless sensing. For future communication and sensing systems, increasing capacity and accuracy is desired, which can be realized at millimeter-wave spectrum from 30 GHz to 300 GHz with several tens of GHz available bandwidth. Wavelength reduces at higher frequency, this implies more compact transceivers and antennas, and high sensing accuracy and imaging resolution. Challenges arise with these application opportunities when it comes to realizing prototype or demonstrators in practice. This thesis proposes some of the solutions addressing such challenges in a laboratory environment.High data rate millimeter-wave transmission experiments have been demonstrated with the help of advanced instrumentations. These demonstrations show the potential of transceiver chipsets. On the other hand, the real-time communication demonstrations are limited to either low modulation order signals or low symbol rate transmissions. The reason for that is the lack of commercially available high-speed analog-to-digital converters (ADCs); therefore, conventional digital synchronization methods are difficult to implement in real-time systems at very high data rates. In this thesis, two synchronous baseband receivers are proposed with carrier recovery subsystems which only require low-speed ADCs [A][B].Besides synchronization, high-frequency signal generation is also a challenge in millimeter-wave communications. The frequency divider is a critical component of a millimeter-wave frequency synthesizer. Having both wide locking range and high working frequencies is a challenge. In this thesis, a tunable delay gated ring oscillator topology is proposed for dual-mode operation and bandwidth extension [C]. Millimeter-wave radar offers advantages for high accuracy sensing. Traditional millimeter-wave radar with frequency-modulated continuous-wave (FMCW), or continuous-wave (CW), all have their disadvantages. Typically, the FMCW radar cannot share the spectrum with other FMCW radars.\ua0 With limited bandwidth, the number of FMCW radars that could coexist in the same area is limited. CW radars have a limited ambiguous distance of a wavelength. In this thesis, a phase-modulated radar with micrometer accuracy is presented [D]. It is applicable in a multi-radar scenario without occupying more bandwidth, and its ambiguous distance is also much larger than the CW radar. Orthogonal frequency-division multiplexing (OFDM) radar has similar properties. However, its traditional fast calculation method, fast Fourier transform (FFT), limits its measurement accuracy. In this thesis, an accuracy enhancement technique is introduced to increase the measurement accuracy up to the micrometer level [E]

    RF CMOS Oscillators for Modern Wireless Applications

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    While mobile phones enjoy the largest production volume ever of any consumer electronics products, the demands they place on radio-frequency (RF) transceivers are particularly aggressive, especially on integration with digital processors, low area, low power consumption, while being robust against process-voltage-temperature variations. Since mobile terminals inherently operate on batteries, their power budget is severely constrained. To keep up with the ever increasing data-rate, an ever-decreasing power per bit is required to maintain the battery lifetime. The RF oscillator is the second most power-hungry block of a wireless radio (after power amplifiers). Consequently, any power reduction in an RF oscillator will greatly benefit the overall power efficiency of the cellular transceiver. Moreover, the RF oscillators' purity limits the transceiver performance. The oscillator's phase noise results in power leakage into adjacent channels in a transmit mode and reciprocal mixing in a receive mode. On the other hand, the multi-standard and multi-band transceivers that are now trending demand wide tuning range oscillators. However, broadening the oscillator’s tuning range is usually at the expense of die area (cost) or phase noise. The main goal of this book is to bring forth the exciting and innovative RF oscillator structures that demonstrate better phase noise performance, lower cost, and higher power efficiency than currently achievable. Technical topics discussed in RF CMOS Oscillators for Modern Wireless Applications include: Design and analysis of low phase-noise class-F oscillators Analyze a technique to reduce 1/f noise up-conversion in the oscillators Design and analysis of low power/low voltage oscillators Wide tuning range oscillators Reliability study of RF oscillators in nanoscale CMO

    Design of Low-Power Short-Distance Transceiver for Wireless Sensor Networks

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    Ph.DDOCTOR OF PHILOSOPH

    Study on wideband voltage controlled oscillator and high efficiency power amplifier ICs for wireless communications

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    制度:新 ; 報告番号:甲3604号 ; 学位の種類:博士(工学) ; 授与年月日:2012/2/20 ; 早大学位記番号:新595

    Frequency Multipliers in SiGe BiCMOS for Local Oscillator Generation in D-band Wireless Transceivers

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    Communications at millimeter-wave (mm-Wave) have drawn a lot of attention in recent years due to the wide available bandwidth which translates directly to higher data transmission capacity. Generation of the transceivers local oscillation (LO) is critical because many contrasting requirements, i.e. tuning range (TR), phase noise (PN), output power, and level of spurious tones, affect the system performance. Differently from what is commonly pursued at Radio Frequency, LO generation with a PLL embedding a VCO at the desired output frequency is not viable at mm-wave. A more promising approach consists of a PLL in the 10-20GHz range, where silicon VCOs feature the best figure of merit, followed by a frequency multiplier. In this thesis, a frequency multiplication chain is investigated to up-convert an LO signal from X-band to D-band by a multiplication factor of 12. The multiplication is done in steps of 3, 2, and 2. A sextupler chip comprises the tripler and the first doubler and the last doubler stage which upconverts the LO signal from E- to D-band is realized in a separate chip, all in a 55nm SiGe BiCMOS technology. The frequency tripler circuit is based on a novel circuit topology which yields a remarkable improvement on the suppression of the driving signal frequency at the output, compared to conventional designs exploiting transistors in class-C. The active core of the circuit approximates the transfer characteristic of a third-order polynomial that ideally produces only a third-harmonic of the input signal. Implemented in a separate break-out chip and consuming 23mW of DC power, the tripler demonstrates ~40dB suppression of the input signal and its 5th harmonic over 16% fractional bandwidth and robustness to power variation of the driving signal over a 15dB range. Including the E-band doubler, the sextupler chip achieves a peak output power of 1.7dBm at 74.4GHz and remains within 2dB variation from 70GHz to 82GHz, corresponding to 16% fractional BW. In this frequency range, the leakages of all harmonics are suppressed by more than 40dBc. The design of the D-band doubler was aimed at delivering high output power with high efficiency and high conversion gain. Toward this end, the efficiency of a push-push pair was improved by a stacked Colpitts oscillator to boost the power conversion gain by 10dB. Moreover, the common-collector configuration keeps separate the oscillator tank from the load, allowing independent optimization of the harmonic conversion efficiency and the load impedance for maximum power delivery. The measured performance of the test chip demonstrated Pout up to 8dBm at 130GHz with 13dB conversion gain and 6.3% Power Added Efficiency

    RF CMOS Oscillators for Modern Wireless Applications

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    While mobile phones enjoy the largest production volume ever of any consumer electronics products, the demands they place on radio-frequency (RF) transceivers are particularly aggressive, especially on integration with digital processors, low area, low power consumption, while being robust against process-voltage-temperature variations. Since mobile terminals inherently operate on batteries, their power budget is severely constrained. To keep up with the ever increasing data-rate, an ever-decreasing power per bit is required to maintain the battery lifetime. The RF oscillator is the second most power-hungry block of a wireless radio (after power amplifiers). Consequently, any power reduction in an RF oscillator will greatly benefit the overall power efficiency of the cellular transceiver. Moreover, the RF oscillators' purity limits the transceiver performance. The oscillator's phase noise results in power leakage into adjacent channels in a transmit mode and reciprocal mixing in a receive mode. On the other hand, the multi-standard and multi-band transceivers that are now trending demand wide tuning range oscillators. However, broadening the oscillator’s tuning range is usually at the expense of die area (cost) or phase noise. The main goal of this book is to bring forth the exciting and innovative RF oscillator structures that demonstrate better phase noise performance, lower cost, and higher power efficiency than currently achievable. Technical topics discussed in RF CMOS Oscillators for Modern Wireless Applications include: Design and analysis of low phase-noise class-F oscillators Analyze a technique to reduce 1/f noise up-conversion in the oscillators Design and analysis of low power/low voltage oscillators Wide tuning range oscillators Reliability study of RF oscillators in nanoscale CMO

    Digital PLL for ISM applications

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    In modern transceivers, a low power PLL is a key block. It is known that with the evolution of technology, lower power and high performance circuitry is a challenging demand. In this thesis, a low power PLL is developed in order not to exceed 2mW of total power consumption. It is composed by small area blocks which is one of the main demands. The blocks that compose the PLL are widely abridged and the final solution is shown, showing why it is employed. The VCO block is a Current-Starved Ring Oscillator with a frequency range from 400MHz to 1.5GHz, with a 300μW to approximately 660μW power consumption. The divider is composed by six TSPC D Flip-Flop in series, forming a divide-by-64 divider. The Phase-Detector is a Dual D Flip-Flop detector with a charge pump. The PLL has less than a 2us lock time and presents a output oscillation of 1GHz, as expected. It also has a total power consumption of 1.3mW, therefore fulfilling all the specifications. The main contributions of this thesis are that this PLL can be applied in ISM applications due to its covering frequency range and low cost 130nm CMOS technology

    On the VCO/Frequency Divider Interface in Cryogenic CMOS PLL for Quantum Computing Applications

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    The availability of quantum microprocessors is mandatory, to efficiently run those quantum al-gorithms promising a radical leap forward in computation capability. Silicon-based nanostruc-tured qubits appear today as a very interesting approach, because of their higher information density, longer coherence times, fast operation gates, and compatibility with the actual CMOS technology. In particular, thanks to their phase noise properties, the actual CMOS RFIC Phase-Locked Loops (PLL) and Phase-Locked Oscillators (PLO) are interesting circuits to synthe-size control signals for spintronic qubits. In a quantum microprocessor, these circuits should op-erate close to the qubits, that is, at cryogenic temperatures. The lack of commercial cryogenic Design Kits (DK) may make the interface between the Voltage Controlled Oscillator (VCO) and the Frequency Divider (FD) a serious issue. Nevertheless, currently this issue has not been sys-tematically addressed in the literature. The aim of the present paper is to investigate the VCO/FD interface when the temperature drops from room to cryogenic. To this purpose, physi-cal models of electronics passive/active devices and equivalent circuits of VCO and the FD were developed at room and cryogenic temperatures. The modeling activity has led to design guide-lines for the VCO/FD interface, useful in the absence of cryogenic DKs

    Energy-Efficient Wireless Connectivity and Wireless Charging For Internet-of-Things (IoT) Applications

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    During the recent years, the Internet-of-Things (IoT) has been rapidly evolving. It is indeed the future of communication that has transformed Things of the real world into smarter devices. To date, the world has deployed billions of “smart” connected things. Predictions say there will be 10’s of billions of connected devices by 2025 and in our lifetime we will experience life with a trillion-node network. However, battery lifespan exhibits a critical barrier to scaling IoT devices. Replacing batteries on a trillion-sensor scale is a logistically prohibitive feat. Self-powered IoT devices seems to be the right direction to stand up to that challenge. The main objective of this thesis is to develop solutions to achieve energy-efficient wireless-connectivity and wireless-charging for IoT applications. In the first part of the thesis, I introduce ultra-low power radios that are compatible with the Bluetooth Low-Energy (BLE) standard. BLE is considered as the preeminent protocol for short-range communications that support transmission ranges up to 10’s of meters. Number of low power BLE transmitter (TX) and receiver (RX) architectures have been designed, fabricated and tested in different planar CMOS and FinFET technologies. The low power operation is achieved by combining low power techniques in both the network and physical layers, namely: backchannel communication, duty-cycling, open-loop transmission/reception, PLL-less architectures, and mixer-first architectures. Further novel techniques have been proposed to further reduce the power the consumption of the radio design, including: a fast startup time and low startup energy crystal oscillators, an antenna-chip co-design approach for quadrature generation in the RF path, an ultra-low power discrete-time differentiator-based Gaussian Frequency Shift Keying (GFSK) demodulation scheme, an oversampling GFSK modulation/demodulation scheme for open loop transmission/reception and packet synchronization, and a cell-based design approach that allows automation in the design of BLE digital architectures. The implemented BLE TXs transmit fully-compliant BLE advertising packet that can be received by commercial smartphone. In the second part of the thesis, I introduce passive nonlinear resonant circuits to achieve wide-band RF energy harvesting and robust wireless power transfer circuits. Nonlinear resonant circuits modeled by the Duffing nonlinear differential equation exhibit interesting hysteresis characteristics in their frequency and amplitude responses that are exploited in designing self-adaptive wireless charging systems. In the magnetic-resonance wireless power transfer scenario, coupled nonlinear resonators are proposed to maintain the power transfer level and efficiency over a range of coupling factors without active feedback control circuitry. Coupling factor depends on the transmission distance, lateral, and angular misalignments between the charging pad and the device. Therefore, nonlinear resonance extends the efficient charging zones of a wireless charger without the requirement for a precise alignment.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169842/1/omaratty_1.pd
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