With the need for higher spectral efficiency and data rates the rise of simultaneous transmit-and-receive (STAR) radios is becoming increasingly valuable. While many systems employ two separate channels for transmit and receive to double the data speed, this comes at the cost of doubling the RF band. This same performance...
The need for sustainably powering unobtrusive internet-of-things applications has led to an interest in energy harvesting. Particularly, the proliferation of wireless communication and devices in the 2.4 GHz Industrial Scientific c Medical (ISM) band creates an opportunity to leverage commonly used devices for RF powering. This dissertation presents a low-quiescent-power...
Wireless localization of objects is useful for several applications that require the knowledge
of position of objects or people. Additionally, power extraction from wireless
signals eliminates the need for wires or any physical connections for charging. This
project is based on system-level testing of an integrated circuit (IC) that combines...
The increasing demand for higher data-rates in spectrum-deficient indoor WiFi networks calls for the adaptation of hybrid systems, consisting of RF and optical wireless channels. The novel hybrid WiFi Free-Space Optical (WIFO) system was introduced to enhance the wireless capacity of indoor WiFi networks. In this thesis, an optical wireless...
This research focuses on receiver architectures which enable better spectral eciency
by handling blockers in the same spectral range as the signal. The presence of
such blockers, without the use of blocker cancelling/ ltering techniques leads to gain
compression and hence, consequent performance degradation of receivers leading to
reduced spectrum...
The deployment of advanced technology standards for 5G and beyond in cellular networks has resulted in interest in integrated circuits (ICs) operating at frequencies above 10GHz. This has sparked research on wideband circuits in commercial low-cost silicon technologies, operating at high RF and mm-wave frequencies. Given the wide range of...
All-digital PLLs promise flexible and precise frequency modulation continous-wave(FMCW) radar signal signal for 77GHz radar applications. Such PLLs require digitally-controlled oscillators(DCO) with wide frequency tuning range and high resolution to address a range of applications and low phase noise requirements. In this thesis, novel resonator structures with ne capacitance/inductance switching...
Scalable array transceivers with wide frequency tuning range are attractive for next-generationradios. Key challenges for such radios include generation of LO signals with widefrequency tuning range, scalable synchronization between multiple array unit cells andtolerance to in-band and out-of-band interferers. This thesis presents approaches toaddress these challenges in commercial CMOS technologies.The...
The increasing demand for higher data-rates is challenging to satisfy with spectrum-deficient indoor WiFi networks. A novel hybrid WiFi Free-Space Optical (WIFO) system has been proposed to enhance the wireless capacity of indoor WiFi networks. In this thesis, an integrated optical wireless receiver is designed and integrated in 65-nm CMOS...
Millimeter-wave (mm-wave) technology promises high speed, high system capacity and low latency interconnects with reduced cost. Applications like high data-rate wireless links, next generation automotive sensors and security body scanners highly depend on mm-wave technology innovations. As operating frequency moves to higher mm-wave bands, shrinking antenna dimensions enable co-integration of...
In recent years, the research community's interest in fully integrated mm-Wave wireless communication systems has increased significantly. With the standards for 5G NR now in place, the focus has shifted to actual deployment. Mm-Wave systems provide wider bandwidths, higher capacity, and lower latency than existing systems such as 4G. Higher...
Spectrum overcrowding, ever increasing demand for high data rate and increased mobility requirements are three major challenges 5G-technology is trying to address. In this thesis I start with a RF front-end technique that deals with blocker interference arising from spectrum overcrowding both across frequency bands and within the same frequency...
Low-power millimeter-wave (mm-wave) transceivers are of interest for achieving energy-efficient high data rate short-reach wireless and guided-wave links.
Spatial modulation or space-shift keying (SSK) can provide energy efficiency improvements by using antenna-switching or transmission direction switching for data modulation. Such links are particularly attractive at millimeter-wave frequencies due to small...
This work presents the design and implementation of a low power phased-array receiver frontend at 28 GHz in 65 nm CMOS. The frontend incorporates a low- power low-noise amplifier(LNA) and a passive reflection-type phase shifter (RTPS) capable of providing 360° phase shift with 5-bit phase resolution and low loss variation....
Low-power receivers (RX) with 100$\mu W$-scale power consumption can enable several power/energy-constrained IoT applications. However, achieving sensitivity, interferer tolerance and wide operating range with low power presents a challenge for existing architectures, particularly those constrained to highly integrated solutions without high-Q off-chip components. Existing solutions rely heavily on high quality...
Real time indoor positioning awareness systems aim to add localization capabilities to upcoming wireless technologies that are quickly becoming an important feature for indoor environment. RF-based impulse-radio ultra-wideband (IR-UWB) is a promising technology for in-door positioning systems due to obstacle penetration capabilities, immunity to multi-path and fading, and high resolution....
The prevalence of Internet-of-Things (IoT) applications leads to an increasing focus on the design and optimization of sensor nodes. Battery lifetime and associated costs of battery replacement often limits the long term operation and viability of sensor nodes. RF wireless energy harvesting on the other hand can be appealing since...
The release of the IEEE802.15.6 standard has led to increased interest in low-power technologies for wireless body-area-networks (WBANs). The power dissipation, supply voltage, and die area are some of the most important criteria for successful WBAN implementations. Digital-intensive RX architectures can potentially result in sub-1V operation with significant reductions in...
Ring amplification has emerged as an efficient technique to drive large capacitive loads in switched capacitor circuits. We propose circuit techniques to demonstrate the first application of a ring amplifier in a non-capacitive feedback system of a LDO. These techniques enable a simple cap-less LDO structure in 180nm CMOS that...
This work presents a new data encoding scheme: Integrated Pulse Width Modulation (iPWM) for equalizing lossy wireline channels with the aim of achieving energy efficient wireline communication. The proposed scheme is able to overcome the fundamental limitations imposed by Manchester and Pulse Width Modulation (PWM) encoding on high data rate...
With explosive growth of Internet access from smart phones and tablets, increasing bandwidth for WIFI system is badly needed. Depending on two years’ research, we produced a novel communication system called WIFO system, which integrates both RF (Radio Frequency) and FSO (Free Space Optical) techniques. WIFO system can significantly increase...
We present a theoretical free-space optical (FSO) transmitter that utilizes a dynamically steered and shaped laser beam to communicate with a randomly moving receiver adorned with a retroreflector. The transmitter tracks the receiver's position by repeatedly scanning the field of view (FOV), measuring reflections from the retroreflector, and estimating the...
For mmWave Integrated Circuit (IC) design, co-integration of passives can reduce size and power consumption, increase reliability, and reduce overall cost. However, skin and proximity effects in the metallization are aggravated at mmWave frequencies, resulting in increased attenuation and degradation of overall performance. Furthermore, tight integration of passive components (to...
This work presents an inductor less switched capacitor based energy harvester, which can simultaneously harvest from 2 energy sources (Solar + Piezo). The proposed harvester employs 2D maximum power point tracking algorithm, by changing the conversion ratios of the charge pumps for piezo and solar sources, and 1D voltage regulation...
Continuous-time ΔΣ modulators are widely used in cellular handsets due to their power efficiency and inherent anti-aliasing characteristics. To achieve demanding cellular bandwidth requirements while maintaining good power efficiency, multi-bit feedback is typically used. This approach provides benefits such as lower OSR, relaxed loop filter requirements, and reduced jitter sensitivity....
The rapid scaling of network bandwidth and data center throughput has motivated the wide adoption of high speed transceivers. Silicon photonics (Si-Photonic) is one of the most promising techniques to realize tightly integrated optical transceivers for next-generation high speed I O standards. This dissertation focuses on the design techniques of...
The design of mobile wireless devices has always focused on reducing power, area, and cost. This dissertation proposes two techniques that are leveraged to save power and area and therefore cost. The first techniques reduces the noise in the receiver and results in a relaxed power requirement. The second technique...
For today’s ubiquitous portable devices, innovative integrated circuits with high performance
yet very low power are necessary. As these devices are used to communicate and sense real world signals in the environment, analog-to-digital converters (ADC) and systems are the key interface circuits needed to digitize the sensed information and they...
Modern sensor network applications are often implemented wirelessly in order to lessen installation costs and reduce deployment times. Unfortunately, these wireless sensor network (WSN) nodes must often rely on batteries or energy harvesting techniques in order to sustain their operation and supply the power needed to maintain communication within the...
Incremental ADCs (IADCs) have found wide applications in sensor interface circuitry since, compared to ∆Σ ADCs, they provide low-latency high-accuracy conversion and easy multiplexing among multiple channels. On the other hand, continuous-time ∆Σ ADCs (CTDSM) have been receiving more and more attention as a power-efficient solution in targeting medium to...
Developments in smart home technology and the Internet of Things have significantly increased the demand for high-speed indoor wireless links. Although the majority of the research conducted in this area is still focused on the efficient usage of radio frequency (RF) spectrum, free-space optical (FSO) networks have also been explored...
Noise-shaping multibit quantizers in a ΔΣ modulator offer extra orders of noise shaping without increasing the loop-filter order and without compromising the stability of the modulator. This dissertation presents two new architectures for improving the overall performance of continuous-time ΔΣ modulators using noise-shaped quantizers.
The first modulator architecture is motivated...
Demands of today's integrated society dependent on communication systems have driven the creation of ever more efficient analog-to-digital converters. For the same reasons, digital circuitry has rapidly expanded to serve all the different systems and needs of consumers. The trend of technology development has been to make these digital circuits...
This dissertation focuses on the analysis, design, and application of inductor-capacitor (LC) oscillators for wireless sensor networks (WSNs).
First an analysis and design optimization approach for enhanced swing, low power CMOS LC oscillators is presented. A phasor based analysis is used for determining the amplitude and phase noise of these...
Several hardware-based security improvements to Near Field Communication (NFC) and Radio-Frequency Identification (RFID) systems are developed and presented. The improvements are intended to be used in conjunction with software encryption to ensure robust security. Two main implementations for a more secure NFC or RFID system are presented: a jamming system,...
Impulse-radio ultra-wide-band (IR-UWB) signaling is a promising technique
for high-speed, short-range relay communications networks. Depending on how
the relay node retransmits the signal, there are two main relay schemes: conventional
one-directional (one-way) relay model, and bi-directional (two-way) relay
model. In bi-directional relay communications, wireless network coding (WNC),
also called physical-layer...
New amplifier architectures are presented using non-traditional methods of biasing. Time-based dynamic biasing and signal-based dynamic biasing are discussed in the context of new architectures. This includes a new form of ring amplification with a dynamic deadzone, allowing for a structure whose coarse path does not consume static power.
This work expands the field of indoor free-space optical communication by introducing novel techniques in short range optical communication. The increasing need for high bandwidth communication necessitates the transition to optical frequencies with hundreds of terahertz worth of unregulated bandwidth. Optical communication offers an inherent security advantage over traditional communications...
Filters and data converters are key analog-and-mixed-signal (AMS) building blocks in communication systems, such as software-defined radios and internet-of-things. In this dissertation, novel switched-capacitor filter and analog-to-digital converter (ADC) circuit configurations have been explored which are power efficient and are digital scaling friendly.
First, a novel switched-capacitor low-pass filter architecture...
Ever increasing global internet data traffic has driven up the demand for cutting-edge high-speed wireline communication systems including SerDes PHY for various interfaces, interconnects, data centers servers and switches in optical systems. Operating wireline communications at higher data rates leads to signals suffering from greater channel loss and exponential increase...
Emerging fifth generation (5G) and beyond 5G communication networks are stimulating the design of radio-frequency (RF) and millimeter-wave (mmWave) integrated circuits for wireless transceivers systems. While co-integration of active circuits and diverse passive components becomes feasible at these high operating frequencies, circuit design is faced with significant challenges due to...
Ring amplifiers (ringamps) have shown excellent power efficiency in the latest state-of-the-art analog to digital converters (ADCs). This thesis describes circuit techniques to ensure robust operation of ringamps using standard analog techniques and proportional-integral-derivative(PID) controller analogy. Large-signal and small-signal analysis of a ringamp are performed using simple RC settling and...
Modern sensors are complex systems comprising multiple sub-systems such as transducers, analog and mixed-signal interface circuits, digital processing circuits, and packaging. Over the last few decades, innovations in these sub-systems combined with their increased integration in complementary metal-oxide semiconductor (CMOS) processes have led to the rapid growth in sensors for...
Time-domain data conversion has recently drawn increased research attention for its highly digital nature in favor of process technology scaling. Also, as the time information being carried by binary voltage, time-domain operation is much less sensitive to voltage noise compared to conventional voltage domain operation. However, for analog-to-digital converter (ADC)...
The Internet of Things (IoT) paradigm brought an ever-increasing dependence on low-power devices to collect sensor data and transmit that information to the cloud, placing greater demand on connectivity and lifespan. In response, rapid worldwide innovation demonstrates the trade-offs in processing, communication, and energy consumption with diverse approaches to low-power...
Harvesting energy from ambient sources can provide power autonomy to energy efficient electronics and sensors. The last decade has seen a multitude of ways to scavenge energy from various sources like solar, thermal, electromagnetic, electrostatic, piezo-electric and many more. Thermal energy from human body heat is ubiquitous and can be...
Cognitive radio technology emerges as a promising solution for overcoming shortage and inefficient use of spectrum resources. In cognitive radio networks, secondary users, which are users equipped with cognitive radios, can opportunistically access spectrum assigned to primary users, the spectrum license holders. Although it improves spectrum utilization efficiency, this opportunistic...
As the CMOS process scales down to submicron, digital circuit performance improves, while reduced supply voltage and lower transistor intrinsic gain make it difficult to implement analog circuits in a power efficient manner. Therefore, it has become advantageous to shift more analog signal processing functions conventionally realized in voltage (analog)...
Wireless sensor networks are becoming important in several monitoring and sensing applications. Ultra low power consumption in the sensor nodes is important for extending the battery life of the nodes. In this dissertation, two low power BFSK receiver architectures are proposed and verified with prototype implementations in silicion.
A 2.4...
With the evolving popularity of new computing platforms such as Ultrabooks, Tablets, and Smart Phones, and the shift to multi-core computing, power is now the key performance limiter, a departure from the traditional frequency limitation. As such, increasingly low-power design solutions feature prominently in early architectural and design space exploration...