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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Development of Low-power Wireless Sensor Nodes based on Assembled Nanowire Devices

Narayanan, Arvind 07 September 2004 (has links)
Networked wireless sensor systems have the potential to play a major role in critical applications including: environmental monitoring of chemical/biological attacks; condition-based maintenance of vehicles, ships and aircraft; real-time monitoring of civil infrastructure including roads, bridges etc.; security and surveillance for homeland defense systems; and battlefield surveillance and monitoring. Such wireless sensor networks can provide remote monitoring and control of operations of large-scale systems using low-power, low-cost, "throw-away" sensor nodes. This thesis focuses on two aspects of wireless sensor node development: (1) post-IC assembly of nanosensor devices onto prefabricated complementary-metal-oxide-semiconductor (CMOS) integrated circuits using a technique called dielectrophoretic (DEP) assembly; and (2) design of a low-power SiGe BiCMOS multi-band ultra-wideband (UWB) transmitter for wireless communications with other nodes and/or a central control unit in a wireless sensor network. For the first part of this work, a DEP assembly test chip was designed and fabricated using the five-metal core CMOS platform technology of Motorola's HiP6W low-voltage 0.18_m Si/SiGe BiCMOS process. The CMOS chip size was 2.5mm x 2.5 mm. The required AC signal for assembling nanowires is provided to the bottom electrodes defined in the Metal 4 (M4) layer of the IC process. This signal is then capacitively coupled to the top/assembly electrodes defined in the top metal (M5) layer that is also interconnected to appropriate readout circuitry. The placement and alignment of the nanowires on the top electrodes are defined by dielectrophoretic forces that act on the nanowires. For proof of concept purposes, metallic rhodium nanowires ((length = 5μm and diameter = 250 nm) were used in this thesis to demonstrate assembly onto the prefabricated CMOS chip. The rhodium nanowires were manufactured using a nanotemplated electroplating technique. In general, the DEP assembly technique can be used to manipulate a wider range of nanoscale devices (nanowire sensors, nanotubes, etc.), allowing their individual assembly onto prefabricated CMOS chips and can be extended to integrate diverse functionalized nanosensors with sensor readout, data conversion and data communication functionalities in a single-chip environment. In addition, this technique provides a highly-manufacturable platform for the development of multifunctional wireless sensor nodes based on assembled nano-sensor devices. The resistances of the assembled nanowires were measured to be on the order of 110 Ω consistent with prior prototype results. Several issues involved in achieving successful assembly of nanowires and good electrical continuity between the nanowires and metal layers of IC processes are addressed in this thesis. The importance of chemical/mechanical planarization (CMP) technique in modern IC processes and considerations for electrical isolation of readout circuit from the assembly sites are discussed. For the second part of this work, a multi-band hopping ultrawideband transmitter was designed to operate in three different frequency bands namely, 4.8 GHz, 6.4 GHz and 8.0 GHz. As a part of this effort, this thesis includes the design of a CMOS phase/frequency detector (PFD), a CMOS pseudo-random code generator and an on-chip passive loop filter, which were designed for the multi-band PLL frequency synthesizer. The CMOS PFD provided phase tracking over a range of -2π to +2π radians. The on-chip passive loop filter was designed for a 62_ phase margin, 250 μA-charge pump output current and 4 MHz-PLL loop-bandwidth. The CMOS pseudorandom code generator provided a two-bit output that helped switch the frequency bands of the UWB transmitter. With all these components, along with a BiCMOS VCO, a CMOS charge pump and a CMOS frequency divider, the simulated PLL frequency synthesizer locked within a relatively short time of 700ns in all three design frequency bands. The die area for the multi-band UWB transmitter as laid out was 1.5 mm x 1.0 mm. Future work proposed by this thesis includes sequential assembly of diverse functionalized gas/chemical nanosensor elements into arrays in order to realize highly sensitive "electronic noses". With integration of such diverse functionalized nano-scale sensors with low-power read-out and data communication system, a versatile and commercially viable low-power wireless sensor system can be realized. / Master of Science
32

5-6 GHz RFIC Front-End Components in Silicon Germanium HBT Technology

Johnson, Daniel Austin 10 May 2001 (has links)
In 1997 the Federal Communications Commission (FCC) released 300 MHz of spectrum between 5-6 GHz designated the unlicensed national information infrastructure (U-NII) band. The intention of the FCC was to provide an unlicensed band of frequencies that would enable high-speed wireless local area networks (WLANs) and facilitate wireless access to the national information infrastructure with a minimum interference to other devices. Currently, there is a lack of cost-effective technologies for developing U-NII band components. With the commercial market placing emphasis on low cost, low power, and highly integrated implementations of RF circuitry, alternatives to the large and expensive distributed element components historically used at these frequencies are needed. Silicon Germanium (SiGe) BiCMOS technology represents one possible solution to this problem. The SiGe BiCMOS process has the potential for low cost since it leverages mature Si process technologies and can use existing Si fabrication infrastructure. In addition, SiGe BiCMOS processes offer excellent high frequency performance through the use of SiGe heterojunction bipolar transistors (HBTs), while coexisting Si CMOS offers compatibility with digital circuitry for high level 'system-on-a-chip' integration. The work presented in this thesis focuses on the development of a SiGe RFIC front-end for operation in the U-NII bands. Specifically, three variants of a packaged low noise amplifier (LNA) and a packaged active x2 sub-harmonic mixer (SHM) have been designed, simulated and measured. The fabrication of the Rifts was through the IBM SiGe foundry; the packaging was performed by RF Micro devices. The mixer and LNA designs were fabricated on separate die, packaged individually, and on-chip matched to a 50 ohm system so they could be fully characterized. Measurements were facilitated in a coaxial system using standard FR4 printed circuit boards. The LNA designs use a single stage, cascoded topology. The input ports are impedance matched using inductive emitter degeneration through bondwires to ground. One version of the LNA uses an shunt inductor/series capacitor output match while the other two variation use a series inductor output match. Gain, isolation, match, linearity and noise figure (NF) were used to characterize the performance of the LNAs in the 5 - 6 GHz frequency band. The best LNA design has a maximum gain of 9 dB, an input VSWR between 1.6:1 and 2:1, an output match between 1.7:1 and 3.6:1, a NF better than 3.9 dB and an input intercept point (IIP3) greater than 5.4 dBm. The LNA operates from a 3.3 V supply voltage and consumes 4 mA of current. The SHM is an active, double-balance mixer that achieves x2 sub-harmonic mixing through two quadrature (I/Q) driven, stacked Gilbert-cell switching stages. Single-ended-to-differential conversion, buffering and I/Q phase separation of the LO signal are integrated on-chip. Measurements were performed to find the optimal operating range for the mixer, and the mixer was characterized under these sets of conditions. It was found that the optimal performance of the mixer occurs at an IF of 250-450 MHz and an LO power of -5 dBm. Under these conditions, the mixer has a measured conversion gain of 9.3 dB, a P_1-dB of -15.7 dBm and an 2LO/RF isolation greater than 35 dB at 5.25 GHz. At 5.775 GHz, the conversion gain is 7.7 dB, the P<sub>1-dB</sub> is -15.0 dBm, and the isolation is greater than 35 dB. The mixer core consumes 9.5 mA from a 5.0 V supply voltage. This work is sponsored by RF Microdevices (RFMD)through the CWT affiliate program.The author was supported under a Bradley Foundation fellowship. / Master of Science
33

ESD Protected SiGe HBT RFIC Power Amplifiers

Muthukrishnan, Swaminathan 27 April 2005 (has links)
Over the last few decades, the susceptibility of integrated circuits to electrostatic discharge (ESD) induced damages has justified the use of dedicated on-chip protection circuits. Design of robust protection circuits remains a challenging task because ESD failure mechanisms have become more acute as device dimensions continue to shrink. A lack of understanding of the ESD phenomena coupled with the increased sensitivity of smaller devices and time-to-market demands has led to a trial-and-error approach to ESD-protected circuit design. Improved analysis capabilities and a systematic design approach are essential to accomplish the challenging task of providing adequate protection to core circuit(s). The design of ESD protection circuitry for RFIC's has been relatively slow to evolve, compared to their digital counterparts, and is now emerging as a new design challenge in RF and high-speed mixed-signal IC development. Sub-circuits which are not embedded in a single System-on-Chip (SOC), such as RF Power amplifiers (PAs), are of particular concern as they are more susceptible to the various ESD events. This thesis presents the development of integrated ESD protection circuitry for two RFIC Power Amplifier designs. A prototype PA for 2.4 GHz Wireless Local Area Network (WLAN) applications was redesigned to provide protection to the RF input and the PA Control pins. A relatively new technique known as the L-C tank approach was used to protect the RFinput while a standard diode ring approach was used to protect the control line. The protection techniques studied were subsequently extended to a completely protected three-stage PA targeting 1.9 GHz Digitally Enhanced Cordless Telephone (DECT) applications. An on-chip shunt-L-series-C input matching network was used to provide ESD protection to the input pin of the DECT PA. A much more area efficient (as compared to the diode ring technique) Zener diode approach was used to protect the control and signal lines. The PA's RF performance was virtually unaffected by the addition of the protection circuits. Both PAs were designed in a commercially available 0.5 ìm SiGe-HBT process. The partially protected WLAN PA was fabricated and packaged in a 3mm x 3mm Fine Pitch Quad Flat Package FQFP-N 12 Lead package and had a measured ESD protection rating of ± 1kV standard Human Body Model (HBM) ESD test. The simulated DECT PA demonstrated +1.5kV/-4kV HBM performance. / Master of Science
34

Integrated Tunable LC Higher-Order Microwave Filters for Interference Mitigation

Amin, Farooq Ul 23 January 2018 (has links)
Modern and future communication and radar systems require highly reconfigurable RF front-ends to realize the vision of Software-Defined Radio (SDR), where a single digitally-enabled radio is able to cover multiple bands and multiple operating standards. However, in the increasingly hostile RF environment, filtering becomes a 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, especially inductors, and to fulfill the tunability requirements a number of active circuit techniques, e.g. N-path, Q-enhanced, discrete-time filters etc., have been developed. Most of these active filtering techniques, however, are limited to RF frequency range of few GHz and below. Additionally, these techniques lack or have very limited bandwidth tunability. On the other hand, Q-enhanced tunable LC filtering has the potential to be implemented at Microwave frequencies from 4~20 GHz and beyond. In this dissertation, a number of Q-enhanced parallel synthesis techniques have been proposed and implemented to achieve high-order, frequency tunable, and wide bandwidth tunable filters. First, a tunable 4th-order BPF was proposed and implemented in Silicon Germanium (SiGe) BiCMOS technology. Along with center frequency tuning, the filter achieves first ever reported 3-dB bandwidth tuning from 2% to 25%, representing 120 MHz to 1.5 GHz of bandwidth at 6 GHz. A new set of design equations were developed for the 4th-order parallel synthesis of BPF. A practical switched varactor control scheme is proposed for large tuning ratio varactors to reduce the nonlinear contribution from the varactor substantially which improves the tunable LC BPF filter linearity. Second, parallel addition and subtraction techniques were proposed to realize tunable dual-band filters. The subtraction technique is implemented in SiGe BiCMOS technology at X and Ku bands with more than 50 dB of out-of-band attenuation. Finally, a true wideband band-reject filter technique was proposed for microwave frequencies using parallel synthesis of two band-pass filters and an all-pass path. The proposed band-reject scheme is tunable and wide 20 dB attenuation bandwidths on the order of 10s of MHz to 100s of MHz can be achieved using this scheme. The implementation of the proposed parallel synthesis techniques in silicon technology along with measured results demonstrate that Q-enhanced filtering is favorable at higher microwave frequencies. Therefore, such implementations are suitable for future wireless communication and radar systems particularly wide bandwidth systems on the order of 100s of MHz to GHz. Future research includes, high-order reconfigurable band-pass and band-reject filters, automatic tuning control, and exploring the parallel synthesis techniques in Gallium Nitride (GaN) technology for high RF power applications. / PHD / The year is 2017 and the current state of the art smartphone can do amazing things using its wireless technologies including LTE, WiFi, Bluetooth, NFC, FM, GPS etc. Each of these wireless standards requires a hardware receiver and a transmitter, also called radio, so as to receive and transmit the signals over air using their designated frequencies. Often more than a single radio is needed to cover different frequency bands, e.g., LTE requires multiple radios to enable operation with different cellular providers and to be used in different countries in cases where the designated frequencies for LTE differs. In order to further reduce the size and cost of communication devices, including but not limited to smartphone, it is desired to implement a single software controlled hardware radio which can cover all of the aforementioned wireless standards. In doing so, the single radio has to distinguish between the desired signal and unwanted signals, also called interference, from other radios using filters that are needed to be reconfigurable to accommodate different wireless standards and bands. The same reconfigurable requirement is valid for radars as well. Therefore, there is a need for the research and development of cost effective and small size dynamic filters which can be controlled from software to adapt to different wireless standards. In this dissertation, a number of filtering techniques are presented to make the radio tunable and agile in terms of operating frequency and bandwidth. The proposed techniques employs very large frequency and bandwidth tuning and are implemented in on-chip integrated circuit (IC) silicon technology. By doing so, the proposed on-chip integrated filters become tens to hundreds of times smaller than traditional off-chip filters which occupies majority of the space in small form factor devices. Therefore, the proposed tunable filters implementations are suitable for future wireless communication and radar systems particularly wide bandwidth systems to increase the data rate and radar detection accuracy.
35

Design of a low-power 60 GHz transceiver front-end and behavioral modeling and implementation of its key building blocks in 65 nm CMOS / Conception et modélisation d'une tête RF à faible consommation pour un émetteur-récepteur à 60 GHz en CMOS 65 nm

Kraemer, Michael M. 03 December 2010 (has links)
La réglementation mondiale, pour des appareils de courte portée, permet l’utilisation sans licence de plusieurs Gigahertz de bande autour de 60 GHz. La bande des 60 GHz répond aux besoins des applications telles que les réseaux de capteurs très haut débit autonome en énergie,ou les transmissions à plusieurs Gbit/s avec des contraintes de consommation d’énergie. Il y a encore peu de temps, les interfaces radios fonctionnant dans la bande millimétrique n’étaient réalisables qu’en utilisant des technologies III-V couteuses. Aujourd’hui, les avancées des technologies CMOS nanométriques permettent la conception et la production en masse des circuits intégrées radiofréquences (RFIC) à faible coût.Cette thèse s’inscrit dans des travaux de recherches dédiés à la réalisation d’un système dans un boîtier (SiP, System in Package) à 60 GHz contenant à la fois l’interface radio (bande de base et circuits RF) ainsi qu’un réseau d’antennes. La première partie de cette thèse est dédiée la conception de la tête RF de l’émetteur-récepteur à faible consommation pour l’interface radio. Les blocs clefs de cette tête RF (amplificateurs, mélangeurs et un oscillateur commandé en tension) sont conçus, réalisés et mesurés en utilisant la technologie CMOS 65 nm de ST Microelectronics. Des éléments actifs et passifs sont développés spécifiquement pour l’utilisation au sein de ces blocs. Une étape importante vers l’intégration de la tête RF complète de l’émetteur-récepteur est l’assemblage de ces blocs de base afin de réaliser une puce émetteur et une puce récepteur. A ce but, une tête RF pour le récepteur a été réalisée. Ce circuit présent une consommation et un encombrement plus réduit que l’état de l’art.La deuxième partie de cette thèse présente le développement des modèles comportementaux des blocs de base conçus. Ces modèles au niveau système sont nécessaires afin de simuler le comportement du SIP, qui devient trop complexe si des modèles détaillés du niveau circuitsont utilisés. Dans cette thèse, une nouvelle technique modélisant le comportement en régime transitoire et régime permanent ainsi que le bruit de phase des oscillateurs commandés en tension est proposée. Ce modèle est implémenté dans le langage de description de matérielVHDL-AMS. La technique proposée utilise des réseaux de neurones artificiels pour approximer la caractéristique non linéaire du circuit. La dynamique est décrite dans l’espace d’état. Grâce à ce modèle, il est possible de réduire d’une façon drastique le temps de calcul des simulations système tout en conservant une excellente précision / Worldwide regulations for short range communication devices allow the unlicensed use of several Gigahertz of bandwidth in the frequency band around 60GHz. This 60GHz band is ideally suited for applications like very high data rate, energy-autonomous wireless sensor networks or Gbit/s multimedia links with low power constraints. Not long ago, radio interfaces that operate in the millimeter-wave frequency range could only be realized using expensive compound semiconductor technologies. Today, the latest sub-micron CMOS technologies can be used to design 60GHz radio frequency integrated circuits (RFICs)at very low cost in mass production. This thesis is part of an effort to realize a low power System in Package (SiP) including both the radio interface (with baseband and RF circuitry) and an antenna array to directly transmit and receive a 60GHz signal. The first part of this thesis deals with the design of the low power RF transceiver front-end for the radio interface. The key building blocks of this RF front-end (amplifiers, mixers and a voltage controlled oscillator (VCO)) are designed, realized and measured using the 65nm CMOS technology of ST Microelectronics. Full custom active and passive devices are developed for the use within these building blocks. An important step towards the full integration of the RF transceiver front-end is the assembly of these building blocks to form basic transmitter and receiver chips. Circuits with small chip size and low power consumption compared to the state of the art have been accomplished.The second part of this thesis concerns the development of behavioral models for the designed building blocks. These system level models are necessary to simulate the behavior of the entire SiP, which becomes too complex when using detailed circuit level models. In particular, a novel technique to model the transient, steady state and phase noise behavior of the VCO in the hardware description language VHDL-AMS is proposed and implemented. The model uses a state space description to describe the dynamic behavior of the VCO. Its nonlinearity is approximated by artificial neural networks. A drastic reduction of simulation time with respect to the circuit level model has been achieved, while at the same time maintaining a very high level of accuracy
36

Design and Evaluation of an Ultra-Low PowerLow Noise Amplifier LNA

yasami, saeed January 2009 (has links)
<p>This master thesis deals with the study of ultra low power Low Noise Amplifier (LNA) for use inmedical implant device. Usually, low power consumption is required for a long battery lifetime andlonger operation. The target technology is 90nm CMOS process.First basic principle of LNA is discussed. Then based on a literature review of LNA design, theproposed LNA is presented in sub-threshold region which reduce power consumption through scalingthe supply voltage and through scaling current.The circuit implementation and simulations is presented to testify the performance of LNA .Besides thepower consumption simulated under the typical supply voltage (1V), it is also measured under someother low supply voltages (down to 0.5V) to investigate the minimum power consumption and theminimum noise figure. Evaluation results show that at a supply voltage of 1V the LNA performs a totalpower consumption of 20mW and a noise of 1dB. Proper performance is achieved with a current ofdown to 200uA and supply voltage of down to 0.45V, and a total power consumption of 200uW</p>
37

Design and Evaluation of an Ultra-Low PowerLow Noise Amplifier LNA

yasami, saeed January 2009 (has links)
This master thesis deals with the study of ultra low power Low Noise Amplifier (LNA) for use inmedical implant device. Usually, low power consumption is required for a long battery lifetime andlonger operation. The target technology is 90nm CMOS process.First basic principle of LNA is discussed. Then based on a literature review of LNA design, theproposed LNA is presented in sub-threshold region which reduce power consumption through scalingthe supply voltage and through scaling current.The circuit implementation and simulations is presented to testify the performance of LNA .Besides thepower consumption simulated under the typical supply voltage (1V), it is also measured under someother low supply voltages (down to 0.5V) to investigate the minimum power consumption and theminimum noise figure. Evaluation results show that at a supply voltage of 1V the LNA performs a totalpower consumption of 20mW and a noise of 1dB. Proper performance is achieved with a current ofdown to 200uA and supply voltage of down to 0.45V, and a total power consumption of 200uW
38

Sensitivity Analysis and Distortion Decomposition of Mildly Nonlinear Circuits

Zhu, Guoji January 2007 (has links)
Volterra Series (VS) is often used in the analysis of mildly nonlinear circuits. In this approach, nonlinear circuit analysis is converted into the analysis of a series of linear circuits. The main benefit of this approach is that linear circuit analysis is well established and direct frequency domain analysis of a nonlinear circuit becomes possible. Sensitivity analysis is useful in comparing the quality of two designs and the evaluation of gradient, Jacobian or Hessian matrices, in analog Computer Aided Design. This thesis presents, for the first time, the sensitivity analysis of mildly nonlinear circuits in the frequency domain as an extension of the VS approach. To overcome efficiency limitation due to multiple mixing effects, Nonlinear Transfer Matrix (NTM) is introduced. It is the first explicit analytical representation of the complicated multiple mixing effects. The application of NTM in sensitivity analysis is capable of two orders of magnitude speedup. Per-element distortion decomposition determines the contribution towards the total distortion from an individual nonlinearity. It is useful in design optimization, symbolic simplification and nonlinear model reduction. In this thesis, a numerical distortion decomposition technique is introduced which combines the insight of traditional symbolic analysis with the numerical advantages of SPICE like simulators. The use of NTM leads to an efficient implementation. The proposed method greatly extends the size of the circuit and the complexity of the transistor model over what previous approaches could handle. For example, industry standard compact model, such as BSIM3V3 [35] was used for the first time in distortion analysis. The decomposition can be achieved at device, transistor and block level, all with device level accuracy. The theories have been implemented in a computer program and validated on examples. The proposed methods will leverage the performance of present VS based distortion analysis to the next level.
39

Fully integrated cmos phase shifter/vco for mimo/ism application

Tavakoli Hosseinabadi, Ahmad Reza 15 May 2009 (has links)
A fully integrated CMOS 0 – 900 phase shifter in 0.18um TSMC technology is presented. With the increasing use of wireless systems in GHz range, there is high demand for integrated phase shifters in phased arrays and MIMO on chip systems. Integrated phase shifters have quite a high number of integrated inductors which consume a lot of area and introduce a huge amount of loss which make them impractical for on chip applications. Also tuning the phase shift is another concern which seems difficult with use of passive elements for integrated applications. This work is presents a new method for implementing phase shifters using only active CMOS elements which dramatically reduce the occupied area and make the tuning feasible. Also a fully integrated millimeter-wave VCO is implemented using the same technology. This VCO can be part of a 24 GHz frequency synthesizer for 24 GHz ISM band transceivers. The 24 GHz ISM band is the unlicensed band and available for commercial communication and automotive radar use, which is becoming attractive for high bandwidth data rate.
40

Low noise RF CMOS receiver integrated circuits

Woo, Sang Hyun 09 February 2012 (has links)
The objective of this research is to design and implement low-noise wideband RFIC components with CMOS technology for the direct-conversion architecture. This research proposes noise reduction techniques to improve the thermal noise and flicker noise contribution of a low noise amplifier (LNA) and a mixer. Of these techniques, the LNA is found to reduce noise, boost gain, and consume a relatively low amount of power without sacrificing the wideband and linearity advantages of a conventional common gate (CG) topology. The research concludes by investigating the proposed mixer topology, which senses and compensates local oscillator (LO) phase mismatches, the dominant cause of flicker noise.

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