Radiation is part of our life. Most people may know a radioactive source is very dangerous. But there are very few situations people are exposed to uncontrolled radionuclides above background. A radioactive source can emit gamma rays which are the highest energy type in electromagnetic radiation.[2] Gamma rays are like...
Modern communication systems often have the ability to transmit signals on multiple communication mediums (e.g., RF, visible light) or interfaces (e.g., MAC layer protocols) at the same time. While each channel has different characteristics, a centralized controller with channel condition information will be able to schedule the resource allocated to...
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...
In the next decade, technology trends--smaller dimension, lower voltage, higher operating frequency--introduce new technical considerations and challenges for radiation effects in integrated circuits. Semiconductor based circuits and traditional dynamic random-access memories will malfunction when exposed to extreme environments, such as space and nuclear reactor. The mechanisms for radiation effect are...
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...
This thesis studies cooperative techniques that rely on femtocell user diversity to improve the downlink communication quality of macrocell users. We analytically analyze and evaluate the achievable performance of these techniques in the downlink of Rayleigh fading channels. We provide an approximation of both the bit-error rate (BER) and the...
The passive charge compensation (PCC) technique was introduced for switched capacitor (SC) circuit to increase the slew rate and enhance the linearity performance, as PCC techniques are used on the Delta-Sigma modulator (DSM) in ADC circuitry. The PCC technique of the project was applied to the design of a SC...
Mg-MOF-74 is one type of metal-organic frameworks (MOFs) that is widely known for its excellent CO2 uptake capacity. More intriguingly, it can be used to detect low levels of toxic gas such as CO2. Currently, most research into Mg-MOF-74 focuses on using the powder type as a CO2 absorbent because...
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 current state of research on gossip techniques for wireless broadcasting is very limited because past research efforts have mostly focused on using gossip techniques for multicast communication. On the other hand, those research efforts that have focused on using gossip techniques for wireless broadcast communications ignore energy efficiency and...
Threshold-based time of arrival (TOA) estimation is a technique for high-precision indoor localization. Existing threshold selection methods, such as xed thresh- old and normalized threshold methods, do not consider the signal-to-noise radio (SNR) value at the receiver. This is not desired for high-precision positioning. A proper threshold value depends on...
We demonstrated a sensitive biosensor based on plasmonic metal composite nanostructures. The device can be fabricated and duplicated with ease using a novel nanoprinting technology which allows precise transfer of metal nanostructures without complicated lithography processes. The design featured by its unique material composition and sub-wavelength structures maximizes the exposure...
Low-distortion architecture is widely used in wideband discrete-time switched-capacitor delta-sigma ADC design. However, it suffers from the power-hungry active adder and critical timing for quantization and dynamic element matching (DEM). To solve this problem, this dissertation presents a delta-sigma modulator architecture with shifted loop delays. In this project, shifted loop...
The primary focus of this thesis is modifying the comprehensive depletion-mode model and extending its applicability to p-channel thin-film transistor (TFT) behavior and subthreshold (subpinchoff) operation. The comprehensive depletion-mode model accurately describes depletion-mode TFT behavior and establishes a set of equations, different from those obtained from square-law theory, which can...
The research presented herein represents an effort to combine the ultra-smooth surface of an amorphous metal thin film (AMTF) with a solution-processed dielectric synthesized via prompt inorganic condensation (PIC). Analysis of dielectric film quality is carried out via electrical measurements of metal-insulator-metal (MIM) diodes. Anneals at 500 and 700 °C...
Linear wireless sensor networks (LWSN) are special class of wireless sensor networks where sensor nodes are deployed in a straight line. Monitoring industrial pipelines, railroads, tunnels, power lines, and borders are applications of LWSNs. Wireless sensors are tiny devices with limited energy resources; therefore, efficient energy routing in LWSNs is...
Data converters are ubiquitous building blocks of a signal chain. The rapid increase in
communication and connectivity devices presents new avenues for pushing the state of
the art analog to digital converters. Techniques for improving resolution, bandwidth,
linearity and bit-error rate, while reducing the power, energy and area is the...
Inter-symbol interference is one of the major factors that make the realization of high-data-rate digital communications system complex. Current designs face two main challenges: how to efficiently utilize the available bandwidth and how to reduce the hardware complexity of the transmitter and receiver. Traditional solutions use a single-band architecture. When...
Pulsed ultra-wideband (UWB) radio uses extremely short pulses to transmit
information. Such pulses provide very fine timing information, which has led to
technological advances in high-precision localization. This thesis focuses on
techniques and experiments of Time-Difference-of-Arrival (TDOA) localization of
a large number of simultaneous sources. First, common localization techniques
such...
The stupendous growth in wireless and mobile devices in the recent years has prompted researchers to look at innovative approaches that enable effective use of the available resources. In this thesis, we propose a medium access control (MAC) protocol, referred to as EM-MAC, that enables wireless devices with multi-channel access...