621 |
Study Of Esd Effects On Rf Power AmplifiersNarasimha, Raju, Divya 01 January 2011 (has links)
Today, ESD is a major consideration in the design and manufacture of ICs. ESD problems are increasing in the electronics industry because of the increasing trend toward higher speed and smaller device sizes. There is growing interest in knowing the effects of ESD protection circuit on the performance of semiconductor integrated circuits (ICs) because of the impact it has on core RF circuit performance. This study investigated the impact of ESD protection circuit on RF Power amplifiers. Even though ESD protection for digital circuits has been known for a while, RF-ESD is a challenge. From a thorough literature search on prior art ESD protection circuits, Silicon controlled rectifier was found to be most effective and reliable ESD protection for power amplifier circuit. A SCR based ESD protection was used to protect the power amplifier and a model was developed to gain better understanding of ESD protected power amplifiers. Simulated results were compared and contrasted against theoretically derived equations. A 5.2GHz fully ESD protected Class AB power amplifier was designed and simulated using TSMC 0.18 um technology. Further, the ESD protection circuit was added to a cascoded Class-E power amplifier operating at 5.2 GHz. ADS simulation results were used to analyze the PA’s RF performance degradation. Various optimization techniques were used to improve the RF circuit performance.
|
622 |
Real-Time Spatial Interference Removal and Maximum Ratio Combining in Communication SystemsWhipple, Adam Gary 14 August 2023 (has links) (PDF)
Radio frequency interference (RFI) is undesired and commonplace. Using a subspace projection method to spatially remove the interference from a phased array system gives results of a 30 dB interference null rejection (INR). Unmanned systems have been developed to observe underwater activity and communicate their observations to passing aircraft. These systems are currently limited by their use of a single transmitter. The uplink can be improved by using a dual-antenna beam steering approach to maximize the signal-to-noise ratio (SNR) the aircraft receives. This approach demonstrates an increase in SNR of 3 dB when compared to a single transmitter.
|
623 |
Scaled Synthetic Aperture Radar System DevelopmentGreen, Ryan K 01 December 2015 (has links) (PDF)
Synthetic Aperture Radar (SAR) systems generate two dimensional images of a target area using RF energy as opposed to light waves used by cameras. When cloud cover or other optical obstructions prevent camera imaging over a target area, SAR can be substituted to generate high resolution images. Linear frequency modulated signals are transmitted and received while a moving imaging platform traverses a target area to develop high resolution images through modern digital signal processing (DSP) techniques. The motivation for this joint thesis project is to design and construct a scaled SAR system to support Cal Poly radar projects. Objectives include low-cost, high resolution SAR architecture development for capturing images in desired target areas. To that end, a scaled SAR system was successfully designed, built, and tested. The current SAR system, however, does not perform azimuthal compression and range cell migration correction (image blur reduction). These functionalities can be pursued by future students joining the ongoing radar project. The SAR system includes RF modulating, demodulating, and amplifying circuitry, broadband antenna design, movement platform, LabView system control, and MATLAB signal processing. Each system block is individually described and analyzed followed by final measured data. To confirm system operation, images developed from data collected in a single target environment are presented and compared to the actual configuration.
|
624 |
Analysis and Design of Silicon based Integrated Circuits for Radio Frequency Identification and Ranging Systems at 24GHz and 60GHz Frequency BandsThayyil, Manu Viswambharan 28 September 2023 (has links)
This scientific research work presents the analysis and design of radio frequency (RF) integrated circuits (ICs) designed for two cooperative RF identification (RFID) proof of concept systems. The first system concept is based on localizable and sensor-enabled superregenerative transponders (SRTs) interrogated using a 24GHz linear frequency modulated continuous wave (LFMCW) secondary radar. The second system concept focuses on low power components for a 60GHz continuous wave (CW) integrated single antenna frontend for interrogating close range passive backscatter transponders (PBTs).
In the 24GHz localizable SRT based system, a LFMCW interrogating radar sends a RF chirp signal to interrogate SRTs based on custom superregenerative amplifier (SRA) ICs. The SRTs receive the chirp and transmit it back with phase coherent amplification. The distance to the SRTs are then estimated using the round trip time of flight method. Joint data transfer from the SRT to the interrogator is enabled by a novel SRA quench frequency shift keying (SQ-FSK) based low data rate simplex communication. The SRTs are also designed to be roll invariant using bandwidth enhanced microstrip patch antennas. Theoretical analysis is done to derive expressions as a function of system parameters including the minimum SRA gain required for attaining a defined range and equations for the maximum number of symbols that can be transmitted in data transfer mode. Analysis of the dependency of quench pulse characteristics during data transfer shows that the duty cycle has to be varied while keeping the on-time constant to reduce ranging errors. Also the worsening of ranging precision at longer distances is predicted based on the non-idealities resulting from LFMCWchirp quantization due to SRT characteristics and is corroborated by system level measurements. In order to prove the system concept and study the semiconductor technology dependent factors, variants of 24GHz SRA ICs are designed in a 130nm silicon germanium (SiGe) bipolar complementary metal oxide technology (BiCMOS) and a partially depleted silicon on insulator (SOI) technology. Among the SRA ICs designed, the SiGe-BiCMOS ICs feature a novel quench pulse shaping concept to simultaneously improve the output power and minimum detectable input power. A direct antenna drive SRA IC based on a novel stacked transistor cross-coupled oscillator topology employing this concept exhibit one of the best reported combinations of minimum detected input power level of −100 dBm and output power level of 5.6 dBm, post wirebonding. The SiGe stacked transistor with base feedback capacitance topology employed in this design is analyzed to derive parameters including the SRA loop gain for design optimization. Other theoretical contributions include the analysis of the novel integrated quench pulse shaping circuit and formulas derived for output voltage swing taking bondwire losses into account. Another SiGe design variant is the buffered antenna drive SRA IC having a measured minimum detected input power level better than −80 dBm, and an output power level greater than 3.2 dBm after wirebonding. The two inputs and outputs of this IC also enables the design of roll invariant SRTs. Laboratory based ranging experiments done to test the concepts and theoretical considerations show a maximum measured distance of 77m while transferring data at the rate of 0.5 symbols per second using SQ-FSK. For distances less than 10m, the characterized accuracy is better than 11 cm and the precision is better than 2.4 cm. The combination of the maximum range, precision and accuracy are one of the best reported among similar works in literature to the author’s knowledge.
In the 60GHz close range CW interrogator based system, the RF frontend transmits a continuous wave signal through the transmit path of a quasi circulator (QC) interfaced to an antenna to interrogate a PBT. The backscatter is received using the same antenna interfaced to the QC. The received signal is then amplified and downconverted for further processing. To prove this concept, two optimized QC ICs and a downconversion mixer IC are designed in a 22nm fully depleted SOI technology. The first QC is the transmission lines based QC which consumes a power of 5.4mW, operates at a frequency range from 56GHz to 64GHz and occupies an area of 0.49mm2. The transmit path loss is 5.7 dB, receive path gain is 2 dB and the tunable transmit path to receive path isolation is between 20 dB and 32 dB. The second QC is based on lumped elements, and operates in a relatively narrow bandwidth from 59.6GHz to 61.5GHz, has a gain of 8.5 dB and provides a tunable isolation better than 20 dB between the transmit and receive paths. This QC design also occupies a small area of 0.34mm² while consuming 13.2mW power. The downconversion is realized using a novel folded switching stage down conversion mixer (FSSDM) topology optimized to achieve one of the best reported combination of maximum voltage conversion gain of 21.5 dB, a factor of 2.5 higher than reported state-of-the-art results, and low power consumption of 5.25mW. The design also employs a unique back-gate tunable intermediate frequency output stage using which a gain tuning range of 5.5 dB is attained. Theoretical analysis of the FSSDM topology is performed and equations for the RF input stage transconductance, bandwidth, voltage conversion gain and gain tuning are derived. A feasibility study for the components of the 60GHz integrated single antenna interrogator frontend is also performed using PBTs to prove the system design concept.:1 Introduction 1
1.1 Motivation and Related Work . . . . . . . . . . . . . . . . . . . . . 1
1.2 Scope and Functional Specifications . . . . . . . . . . . . . . . . . 4
1.3 Objectives and Structure . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Features and Fundamentals of RFIDs and Superregenerative Amplifiers 9
2.1 RFID Transponder Technology . . . . . . . . . . . . . . . . . . . . 9
2.1.1 Chipless RFID Transponders . . . . . . . . . . . . . . . . . 10
2.1.2 Semiconductor based RFID Transponders . . . . . . . . . . 11
2.1.2.1 Passive Transponders . . . . . . . . . . . . . . . . 11
2.1.2.2 Active Transponders . . . . . . . . . . . . . . . . . 13
2.2 RFID Interrogator Architectures . . . . . . . . . . . . . . . . . . . 18
2.2.1 Interferometer based Interrogator . . . . . . . . . . . . . . . 19
2.2.2 Ultra-wideband Interrogator . . . . . . . . . . . . . . . . . . 20
2.2.3 Continuous Wave Interrogators . . . . . . . . . . . . . . . . 21
2.3 Coupling Dependent Range and Operating Frequencies . . . . . . . 25
2.4 RFID Ranging Techniques . . . . . . . . . . . . . . . . . . . . . . . 28
2.4.0.1 Received Signal Strength based Ranging . . . . . 28
2.4.0.2 Phase based Ranging . . . . . . . . . . . . . . . . 30
2.4.0.3 Time based Ranging . . . . . . . . . . . . . . . . . 30
2.5 Architecture Selection for Proof of Concept Systems . . . . . . . . 32
2.6 Superregenerative Amplifier (SRA) . . . . . . . . . . . . . . . . . . 35
2.6.1 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.6.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . 42
2.6.3 Frequency Domain Characteristics . . . . . . . . . . . . . . 45
2.7 Semiconductor Technologies for RFIC Design . . . . . . . . . . . . 48
2.7.1 Silicon Germanium BiCMOS . . . . . . . . . . . . . . . . . 48
2.7.2 Silicon-on-Insulator . . . . . . . . . . . . . . . . . . . . . . . 48
3 24GHz Superregenerative Transponder based Identification and Rang-
ing System 51
3.1 System Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.1.1 SRT Identification and Ranging . . . . . . . . . . . . . . . . 51
3.1.2 Power Link Analysis . . . . . . . . . . . . . . . . . . . . . . 55
3.1.3 Non-idealities . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.1.4 SRA Quench Frequency Shift Keying for data transfer . . . 61
3.1.5 Knowledge Gained . . . . . . . . . . . . . . . . . . . . . . . 63
3.2 RFIC Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.2.1 Low Power Direct Antenna Drive CMOS SRA IC . . . . . . 66
3.2.1.1 Circuit analysis and design . . . . . . . . . . . . . 66
3.2.1.2 Characterization . . . . . . . . . . . . . . . . . . . 69
3.2.2 Direct Antenna Drive SiGe SRA ICs . . . . . . . . . . . . . 71
3.2.2.1 Stacked Transistor Cross-coupled Quenchable Oscillator
. . . . . . . . . . . . . . . . . . . . . . . . 72
3.2.2.1.1 Resonator . . . . . . . . . . . . . . . . . . 72
3.2.2.1.2 Output Network . . . . . . . . . . . . . . 75
3.2.2.1.3 Stacked Transistor Cross-coupled Pair and
Loop Gain . . . . . . . . . . . . . . . . . 77
3.2.2.2 Quench Waveform Design . . . . . . . . . . . . . . 85
3.2.2.3 Characterization . . . . . . . . . . . . . . . . . . . 89
3.2.3 Antenna Diversity SiGe SRA IC with Integrated Quench
Pulse Shaping . . . . . . . . . . . . . . . . . . . . . . . . . . 91
3.2.3.1 Circuit Analysis and Design . . . . . . . . . . . . 91
3.2.3.1.1 Crosscoupled Pair and Sampling Current 94
3.2.3.1.2 Common Base Input Stage . . . . . . . . 95
3.2.3.1.3 Cascode Output Stage . . . . . . . . . . . 96
3.2.3.1.4 Quench Pulse Shaping Circuit . . . . . . 96
3.2.3.1.5 Power Gain . . . . . . . . . . . . . . . . . 99
3.2.3.2 Characterization . . . . . . . . . . . . . . . . . . . 102
3.2.4 Knowledge Gained . . . . . . . . . . . . . . . . . . . . . . . 103
3.3 Proof of Principle System Implementation . . . . . . . . . . . . . . 106
3.3.1 Superregenerative Transponders . . . . . . . . . . . . . . . 106
3.3.1.1 Bandwidth Enhanced Microstrip Patch Antennas 108
3.3.2 FMCW Radar Interrogator . . . . . . . . . . . . . . . . . . 114
3.3.3 Chirp Z-transform Based Data Analysis . . . . . . . . . . . 116
4 60GHz Single Antenna RFID Interrogator based Identification System 121
4.1 System Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
4.2 RFIC Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
4.2.1 Quasi-circulator ICs . . . . . . . . . . . . . . . . . . . . . . 125
4.2.1.1 Transmission Lines based Quasi-Circulator IC . . 126
4.2.1.2 Lumped Elements WPD based Quasi-Circulator . 130
4.2.1.3 Characterization . . . . . . . . . . . . . . . . . . . 134
4.2.1.4 Knowledge Gained . . . . . . . . . . . . . . . . . . 135
4.2.2 Folded Switching Stage Downconversion Mixer IC . . . . . 138
4.2.2.1 FSSDM Circuit Design . . . . . . . . . . . . . . . 138
4.2.2.2 Cascode Transconductance Stage . . . . . . . . . . 138
4.2.2.3 Folded Switching Stage with LC DC Feed . . . . . 142
4.2.2.4 LO Balun . . . . . . . . . . . . . . . . . . . . . . . 145
4.2.2.5 Backgate Tunable IF Stage and Offset Correction 146
4.2.2.6 Voltage Conversion Gain . . . . . . . . . . . . . . 147
4.2.2.7 Characterization . . . . . . . . . . . . . . . . . . . 150
4.2.2.8 Knowledge Gained . . . . . . . . . . . . . . . . . . 151
4.3 Proof of Principle System Implementation . . . . . . . . . . . . . . 154
5 Experimental Tests 157
5.1 24GHz System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
5.1.1 Ranging Experiments . . . . . . . . . . . . . . . . . . . . . 157
5.1.2 Roll Invariance Experiments . . . . . . . . . . . . . . . . . . 158
5.1.3 Joint Ranging and Data Transfer Experiments . . . . . . . 158
5.2 60GHz System Detection Experiments . . . . . . . . . . . . . . . . 165
6 Summary and Future Work 167
Appendices 171
A Derivation of Parameters for CB Amplifier with Base Feedback Capac-
itance 173
B Definitions 177
C 24GHz Experiment Setups 179
D 60 GHz Experiment Setups 183
References 185
List of Original Publications 203
List of Abbreviations 207
List of Symbols 213
List of Figures 215
List of Tables 223
Curriculum Vitae 225
|
625 |
Using computational methods for the prediction of drug vehiclesMistry, Pritesh, Palczewska, Anna Maria, Neagu, Daniel, Trundle, Paul R. January 2014 (has links)
No / Drug vehicles are chemical carriers that aid a drug's passage through an organism. Whilst they possess no intrinsic efficacy they are designed to achieve desirable characteristics which can include improving a drug's permeability and or solubility, targeting a drug to a specific site or reducing a drug's toxicity. All of which are ideally achieved without compromising the efficacy of the drug. Whilst the majority of drug vehicle research is focused on the solubility and permeability issues of a drug, significant progress has been made on using vehicles for toxicity reduction. Achieving this can enable safer and more effective use of a potent drug against diseases such as cancer. From a molecular perspective, drugs activate or deactivate biochemical pathways through interactions with cellular macromolecules resulting in toxicity. For newly developed drugs such pathways are not always clearly understood but toxicity endpoints are still required as part of a drug's registration. An understanding of which vehicles could be used to ameliorate the unwanted toxicities of newly developed drugs would be highly desirable to the pharmaceutical industry. In this paper we demonstrate the use of different classifiers as a means to select vehicles best suited to avert a drug's toxic effects when no other information about a drug's characteristics is known. Through analysis of data acquired from the Developmental Therapeutics Program (DTP) we are able to establish a link between a drug's toxicity and vehicle used. We demonstrate that classification and selection of the appropriate vehicle can be made based on the similarity of drug choice.
|
626 |
Hybrid Radio Frequency and Video Framework for Identity-Aware Augmented Perception in Disaster Management and Assistive TechnologiesYu, Xunyi 01 September 2013 (has links)
In this dissertation, we introduce a hybrid radio frequency and video framework that enables identity aware-augmented perception. Identity-aware augmented perception enhances users' perception of the surrounding by collecting and analyzing information pertaining to each identifiable or tractable target nearby aggregated from various sensors, and presents it visually or audibly augmenting users' own sensory perceptions. We target two application areas of disaster management and assistive technologies. Incident commanders and first responders can use the technology to perceive information specific to a victim, e.g. triage level, critical conditions, visually superimposed on third person or first person video. The blind and visually impaired can use the technology to perceive the direction and distance of static landmarks and moving people nearby, and target specific information, e.g. a store's name and opening hours, a friend's status on social networks.
Identifying who is who in video is an important yet challenging problem that can greatly benefit existing video analytics and augmented reality applications. Identity information can be used to improve the presentation of target information on graphical user interface, enable role-based target analytics over long term, and achieve more efficient and accurate surveillance video indexing and querying. Instead of relying on target appearance, we propose a hybrid approach that combines complimentary radio frequency (RF) signal with video to identify targets. Recovering target identities in video using RF is not only useful in its own right, but also provides an alternative formulation that helps to solve difficult problems in individual video and RF domains, e.g., persistent video tracking, accurate target localization using RF signal, anchorless target localization, multi-camera target association, automatic RF and video calibration.
We provide a comprehensive RF and video fusion framework to enable identity-aware augmented perception in a variety of scenarios. We propose a two stage data fusion scheme based on tracklets, and formulate the tracklet identification problem under different RF and camera measurement models using network flow or graphical model. We first start from a basic calibrated single fixed camera, fixed RF readers configuration. Then we consider anchorless target identification using pair-wise measurements between mobile RF devices to reduce deployment complexity. Then we incorporate multiple cameras, to improve coverage, camera deployment flexibility, identification accuracy and enable multi-view augmented perception.
We propose a self-calibrating identification algorithm, that simplifies manual calibration and improve identification accuracy in environments with obstruction. Finally, we solve the problem of annotating video taken by mobile cameras to provide first-person perception, taking advantage of target appearance, location and identity given by the fixed video hybrid system.
|
627 |
Creating a MATLAB Tool that allows for S-Parameter Perturbation in a Cascaded SystemFields, Ann 26 January 2023 (has links)
No description available.
|
628 |
Synergistic Multi-Source Ambient Radio Frequency and Thermal Energy Harvesting for IoT ApplicationsBakytbekov, Azamat 10 1900 (has links)
The Internet of Things (IoT) is an infrastructure of physical objects connected via the Internet that can exchange data to achieve efficient resource management. Billions of devices must be self-powered and low-cost considering the massive scale of the IoT. Thus, there is a need for low-cost ambient energy harvesters to power IoT devices. It is a challenging task since ambient energy might be unpredictable, intermittent and insufficient. For example, solar energy has limitations such as intermittence and unpredictability despite utilizing the highest power availability and relatively mature technology. Designing a multi-source energy harvester (MSEH) based on continuous and ubiquitous ambient energy sources might alleviate these issues by providing versatility and robustness of power supply. However, combining several energy harvesters into one module must be done synergistically to ensure miniaturization, compactness and more collected energy. Also, additive manufacturing techniques must be used to achieve low-cost harvesters and mass manufacturability.
This dissertation presents two different kind of ambient energy harvesters, namely radio frequency energy harvester (RFEH) and thermal energy harvester (TEH). Each harvester is individually optimized and then synergistically combined into a MSEH. First, RFEH is designed for triple-band harvesting (GSM900, GSM1800, 3G2100) using the antenna-on-package concept and fabricated through 3D and screen printing. TEH collects energy from temperature fluctuations of ambient environment through a combination of thermoelectric generators and phase change materials. It is adapted specifically for the desert conditions of Saudi Arabia. Later, TEH and RFEH are combined to realize MSEH. Smart integration is achieved by designing a dual-function component, heatsink antenna, that serves as a receiving antenna of RFEH and a heatsink of TEH. The heatsink antenna has been optimized for both antenna radiation performance and heat transfer performance. Field tests showed that the MSEH can collect 3680μWh energy per day and the outputs of TEH and RFEH have increased 4 and 3 times compared to the independent TEH and RFEH respectively. To validate the utility of the MSEH, a temperature/humidity sensor has been successfully powered by the MSEH. Overall, sensor’s data can be wirelessly transmitted with time intervals of 3.5s, highlighting the effectiveness of the synergistic MSEH.
|
629 |
Space and Spectrum Engineered High Frequency Components and CircuitsArigong, Bayaner 05 1900 (has links)
With the increasing demand on wireless and portable devices, the radio frequency front end blocks are required to feature properties such as wideband, high frequency, multiple operating frequencies, low cost and compact size. However, the current radio frequency system blocks are designed by combining several individual frequency band blocks into one functional block, which increase the cost and size of devices. To address these issues, it is important to develop novel approaches to further advance the current design methodologies in both space and spectrum domains. In recent years, the concept of artificial materials has been proposed and studied intensively in RF/Microwave, Terahertz, and optical frequency range. It is a combination of conventional materials such as air, wood, metal and plastic. It can achieve the material properties that have not been found in nature. Therefore, the artificial material (i.e. meta-materials) provides design freedoms to control both the spectrum performance and geometrical structures of radio frequency front end blocks and other high frequency systems. In this dissertation, several artificial materials are proposed and designed by different methods, and their applications to different high frequency components and circuits are studied. First, quasi-conformal mapping (QCM) method is applied to design plasmonic wave-adapters and couplers working at the optical frequency range. Second, inverse QCM method is proposed to implement flattened Luneburg lens antennas and parabolic antennas in the microwave range. Third, a dual-band compact directional coupler is realized by applying artificial transmission lines. In addition, a fully symmetrical coupler with artificial lumped element structure is also implemented. Finally, a tunable on-chip inductor, compact CMOS transmission lines, and metamaterial-based interconnects are proposed using artificial metal structures. All the proposed designs are simulated in full-wave 3D electromagnetic solvers, and the measurement results agree well with the simulation results. These artificial material-based novel design methodologies pave the way toward next generation high frequency circuit, component, and system design.
|
630 |
A Radio-Frequency Synchronization System for Fiber-Optic Quantum NetworksStephen Donahue Chapman (18072259) 29 February 2024 (has links)
<p dir="ltr">This thesis discusses the use of a fiber optic system to synchronize GHz frequency radio-frequency signals over distances of up to 5 km and its future applications in quantum communications. The stability of the synchronization is assessed by an ‘identity gate’, where each radio-frequency signal drives a phase modulator, and the frequency profile of a continuous wave laser sent through both modulators indicates the stability of the RF signals relative to one another. Experimental results indicate that 19 GHz signals synchronized over 5.5 km drifted less than 1 ps over 30 minutes. This is superior to the radio-frequency synthesizers’ built in synchronization method and to other commonly used protocols. To illustrate an application, the system was employed in a quantum nonlocal modulation cancellation experiment. Joint spectral characterization of the biphotons shows that this synchronization scheme can be used for nodes in a quantum communications network. More specifically, possible future applications of this technology include use in a photonic quantum local area network at Oak Ridge National Laboratories.</p>
|
Page generated in 0.0525 seconds