Empirical mode decomposition was proposed recently as a time frequency analysis tool for nonlinear and nonstationary signals. Despite from its many advantages, problems such as “uniqueness” problem have been discovered which limit the application. Although this problem has been addressed to some extent by various extensions of the original algorithm, the solution is far from satisfactory in some scenarios. In this work we propose two variants of the original algorithm, with emphasis on providing unified representations. R-EMD makes use of a set of reference signals to guide the decomposition therefore guarantees unified representation for multiple 1D signals. 2D- BEMD takes advantage of a projection procedure and is capable of providing unified representation between a pair of 2D signals. Application of the proposed algorithms on different problems in biometric and image processing demonstrates promising results and indicates the effectiveness of the proposed framework.

Compressed sensing is an emerging field, which proposes that a small collection of linear projections of a sparse signal contains enough information for perfect reconstruction of the signal. In this thesis, we study the general problem of modeling and reconstructing spatially or temporally correlated sparse signals in a distributed scenario. The correlation among signals provides an additional information, which could be captured by joint sparsity models. After modeling the correlation, we propose two different reconstruction algorithms that are able to successfully exploit this additional information. The first algorithm is a very fast greedy algorithm, which is suitable for large scale problems and can exploit spatial correlation. The second algorithm is based on a thresholding algorithm and can exploit both the temporal and spatial correlation. We also generalize the standard joint sparsity model and propose a new model for capturing the correlation in the sensor networks.

A fundamental study of the correlations between ion energy, substrate temperature, and plasma density with hydrogen content, percent sp2 bonding, optical gap, and refractive index of hydrogenated amorphous carbon (a-C) films is presented. A strong dependency between the ion energy used during deposition and the film’s microstructure is shown. Moreover, it is revealed that the optical properties of the a-C films are controlled by the concentration and size of sp2 clusters in the film. Through N2 mixing in the source gas, room-temperature nitrogen doped polymeric-like a-C films were demonstrated for the first time. X-ray Photoelectron Spectroscopy revealed an increase in the Fermi level of these films with increased nitrogen content. A proof-of-concept a-C based transparent heat mirror (THM) was demonstrated. It was shown that a-C acts as an oxygen-free protective barrier and anti-reflective coating for Ag films in the THM, increasing the transmission in the visible region by 10-20%.

This thesis describes 80−94GHz and 70−77GHz interpolating phase shifters and the corresponding transmitter and receiver ICs, fabricated in 65-nm CMOS and SiGe BiCMOS technologies, respectively. Lumped inductors and transformers are employed to realize small-form factor 90 degree hybrids as needed in high density phased arrays. The CMOS transmitter exhibits absolute phase and amplitude errors of 4 degrees and 4dB, respectively, at 90GHz, when the phase is varied from 0 degrees to 360 degrees in steps of 22.5 degrees. The absolute phase error in the SiGe BiCMOS receiver is less than 5 degrees, with a maximum gain imbalance below 3dB at 74GHz. The peak gain and power consumption are 3.8dB and 142mW from 1.2V supply for the CMOS transmitter, and 17dB and 128mW from 1.5V and 2.5V supplies for the SiGe BiCMOS receiver.

Two laptop antennas are presented using two different designs based on metamaterials. The first design consists of planar monopole loaded with an electric-LC resonator (ELC). This novel topology allows for the realization of a multi-band antenna by using the ELC to add multiple resonances. This structure is analyzed using full-wave simulations. A circuit model is also developed to gain further understanding. This technique is then used to design a Wi-Fi antenna. The second design uses a modified double-tuned matching network to create a single-band match for a planar monopole antenna. The matching network is implemented using a complementary-split-ring-resonator (CSRR). The design is once again analyzed using full-wave simulations and a circuit model is also developed. This technique is then applied to design a WiMax antenna. Both the Wi-Fi and WiMax antennas are fabricated and show good agreement between the simulated and measured results.

In this work, we investigate the performance of full-rate full-diversity space-time codes (FRFD-STCs) under practical conditions. In this thesis, we first discuss the performance of FRFD-STCs in the moderate SNR region. We also compare FRFD-STCs with spatial multiplexing, using the same transmission rate, for both un-coded and coded systems. The results show that spatial multiplexing is as good as FRFD-STCs with channel coding. Secondly, we investigate the issue of quantization, i.e. the effect of the quantization error in the space-time encoding matrix. Our analysis and results show that the performance loss is negligible. Finally, we propose two receiver structures in the presence of imperfect channel state information (CSI). The two receivers use the VEM module as the channel estimator and MIMO detector respectively. Both receivers are of low complexity, and have better performance than the methods proposed previously.

Field Programmable Gate Array (FPGA) devices are increasing in capacity at an exponential rate, and thus there is an increasingly strong demand to accelerate simulated annealing placement. Graphics Processing Units (GPUs) offer a unique opportunity to accelerate this simulated annealing placement on a manycore architecture using only commodity hardware. GPUs are optimized for applications which can tolerate single-thread latency and so GPUs can provide high throughput across many threads. However simulated annealing is not embarrassingly parallel and so single thread latency should be minimized to improve run time. Thus it is questionable whether GPUs can achieve any speedup over a sequential implementation. In this thesis, a novel subset-based simulated annealing placement framework is proposed, which specifically targets the GPU architecture. A highly optimized framework is implemented which, on average, achieves an order of magnitude speedup with less than 1% degradation for wirelength and no loss in quality for timing on realistic architectures.

In this thesis, planar photonic crystals for optofluidic biosensing applications are analyzed. Planar photonic crystals are optically resonant structures which possess modal characteristics which can be exploited for biosensing applications. Sensing is achieved by detecting changes in refractive index due to analyte interactions in a sampled fluid. This work describes a broad study of photonic crystal slab sensors, with special consideration to biosensing. Outlined are considerations pertaining to sensing figures of merit, device fabrication, and performance. Results of simulations and device characterization indicate that planar photonic crystals possess sensing attributes similar or better than existing optically resonant refractive index sensors, such as surface plasmon resonance, grating, and interferometric waveguide sensors. Additionally, these photonic crystals can be patterned in large-areas which enable a simple light coupling scheme. All considered, their appeal as a biosensing solution is justified in the area of in vitro diagnostics.

This thesis proposes a clustering algorithm for vehicular communication networks. A novel clustering metric and an improved clustering framework are introduced. The novel clustering metric, network criticality, is a global metric on undirected graphs which quantifies the robustness of the graph against changes in environmental parameters, and point-to-point network criticality is also defined to measure the resistance between different points of a graph. We localize the notion of network criticality for a node of a vehicular network which can potentially be promoted as the cluster header. We use the localized notion of node criticality in conjunction with a universal link metric, Link Expiration Time (LET), to derive a clustering algorithm for the vehicular network. We employ a distributed multi-hop clustering algorithm based on the notion of network criticality. Simulation results show that the proposed clustering algorithm forms a more robust cluster structure.

Photonic crystals (PC) are periodic structures that dictate the behavior of electromagnetic radiation and can be one-dimensional, two-dimensional or three-dimensional (3D). A 3DPC was modeled and fabricated based on a three-layer design resulting in a face centered cubic structure. Different simulation methods were used to show the existence of a complete 3D bandgap, and were verified experimentally by obtaining transmission measurements in several directions. A prototype of the structure was fabricated using ECCOSTOCK HiK high dielectric sheets (dielectric of 12) and machined using a computer and numerical controlled mill. Experiments to test this structure were performed in an anechoic chamber making use of a network analyzer, a pair of horn antennas, collimating lenses, and a track for alignment. Free-space Thru-Reflect-Line measurements were taken between 10GHz and 15GHz to obtain the transmission through the prototype. Finally, a defect layer was added to the structure at different locations and localized modes observed.