Master of Science in Electrical Engineering (MSEE), Wright State University, 2023, Electrical Engineering

A method for software-defined radio array calibration is presented. The method implements a matched filter approach to calculate the phase shift between channels. The temporal stability of the system and calibration coefficients are shown through the standard deviation over the course of four weeks. The standard deviation of the phase correction was shown to be less than 2 deg. for most channels in the array and within 8 deg. for the most extreme case. The standard deviation in amplitude scaling was calculated to be less than 0.06 for all channels in the array. The performance of the calibration is evaluated by the antenna gain and the difference from the ideal beam shape for the peak side lobe level and first null depth. For one example data collection, the gain was 61 dB for the array with a maximum difference of 0.2246 dB for the peak side lobe level and 0.3998 dB for the first null depth.

Committee: Michael A. Saville Ph.D. (Advisor); Zhiqiang Wu Ph.D. (Committee Member); Josh Ash Ph.D. (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy (PhD), Wright State University, 2022, Electrical Engineering

5th generation wireless systems (5G) have expanded frequency band coverage with the low-band 5G and mid-band 5G frequencies spanning 600 MHz to 4 GHz spectrum. This dissertation focuses on a microelectronic implementation of CMOS 65 nm design of an All-Digital Phase Lock Loop (ADPLL), which is a critical component for advanced 5G wireless transceivers. The ADPLL is designed to operate in the frequency bands of 600MHz-930MHz, 2.4GHz-2.8GHz and 3.4GHz-4.2GHz. Unique ADPLL sub-components include: 1) Digital Phase Frequency Detector, 2) Digital Loop Filter, 3) Channel Bank Select Circuit, and 4) Digital Control Oscillator. Integrated with the ADPLL is a 90-degree active RC-CR phase shifter with on-line amplitude locked loop (ALL) calibration to facilitate enhanced image rejection while mitigating the effects of fabrication process variations and component mismatch. A unique high-sensitivity high-speed dynamic voltage comparator is included as a key component of the active phase shifter/ALL calibration subsystem. 65nm CMOS technology circuit designs are included for the ADPLL and active phase shifter with simulation performance assessments. Phase noise results for 1 MHz offset with carrier frequencies of 600MHz, 2.4GHz, and 3.8GHz are -130, -122, and -116 dBc/Hz, respectively. Monte Carlo simulations to account for process variations/component mismatch show that the active phase shifter with ALL calibration maintains accurate quadrature phase outputs when operating within the frequency bands 600MHz-930MHz, 2.4GHz-2.8GHz and 3.4GHz-4.2GHz.

Committee: Saiyu Ren Ph.D. (Advisor); Raymond E. Siferd Ph.D. (Committee Member); Yan Zhuang Ph.D. (Committee Member); Henry Chen Ph.D. (Committee Member); Marian K. Kazimierczuk Ph.D. (Committee Member) Subjects: Electrical Engineering

Master of Science in Electrical Engineering (MSEE), Wright State University, 2023, Electrical Engineering

Calibration plays a critical role in the optimal performance of algorithms in digital beamforming arrays. Phase incoherency between elements results in poor beamforming with decreased gain and higher sidelobes, leading to a decrease in accuracy and sensitivity of measurements. A similar problem exists in performing multi-pass interferometric SAR (IFSAR) processing of SAR data stacks to generate topological maps of the scene, where phase errors translate to height errors. By treating each SAR image in the data stack like an element of a uniform linear array, this thesis explores several phase calibration techniques that can be used to calibrate digital beamforming arrays and introduces them to IFSAR processing to calibrate the SAR images. Three data-driven techniques are selected, where calibration coefficients are obtain using sources of opportunity, via a contrast-based method, and via a clutter-based method. These calibration algorithms are then demonstrated on synthetic data of a simulated scene, consisting of scatterers at different heights, and with added phase incoherency to the SAR images. Processing of the simulated data shows an improvement in height estimation of the scatterers, including an evident increase in the gain and focusing of the scatterers in the scene after calibration. Phase calibration is then introduced to the processing of measured Gotcha data, where results also show gain and focusing improvement of the scatterers. Additional research, however, will be needed to associate the height estimation of the scatterers in these results with ground truth data to ascertain an absolute height map of the scene.

Committee: Brian D. Rigling Ph.D. (Advisor); Michael A. Saville Ph.D., P.E. (Committee Member); Fred Garber Ph.D. (Committee Member); Josh Ash Ph.D. (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2008, Materials Science and Engineering

A methodology that integrates the phase field model with simpler models was developed to study the early stages of microstructural development in nickel base superalloys under non-isothermal conditions, allowing for faster, more comprehensive examination of the experimental system. Additionally, the parameters required for calibrating a phase field model were examined for uncertainty, and a comprehensive method for linking experimental data to a model was developed. The methodology developed was applied to analyze the formation of bimodal particle size distributions during linear continuous cooling. The dynamic competition for supersaturation by growth of existing precipitates and nucleation of new particles was modeled. The nucleation rate was calculated according to classical nucleation theory as function of local supersaturation and temperature. The depletion of matrix super-saturation by growth of existing particles was calculated from fully diffusion-controlled precipitate growth in an infinite matrix. Phase field simulations of γ' precipitation in a binary Ni-Al alloy were performed under continuous cooling conditions. Then the average and maximum matrix supersaturations were calculated and plotted onto the contours of nucleation rate and growth rate in concentration and temperature space. These methods were used iteratively to identify the window for bimodal particle size distributions. Combining the models of different complexities produced a much more comprehensive understanding of the competing dynamics involved early in microstructure formation. A systemic method for calibrating a model to experimental alloy systems was developed. Calibrated to isothermal aging data along with literature, database and parametric values, a phase field model reproduced the precipitation kinetics. Quantitative phase field modeling techniques were developed to control the influence of uncertainty in the original data sources for model inputs. Using more data sources t (open full item for complete abstract)

Committee: Yunzhi Wang PhD (Advisor); Jeff Simmons PhD (Committee Member); Suliman Dregia PhD (Committee Member); Michael Mills PhD (Committee Member) Subjects: Engineering; Materials Science

Master of Science (MS), Ohio University, 2013, Electrical Engineering (Engineering and Technology)

This thesis presents a demonstrated method for the performance of a calibration method for a controlled reception pattern antenna (CRPA) using a Software Defined Radio (SDR) configuration. The combination CRPA and SDR system consists of a low-cost 7-element configuration where the antenna RF inputs are feed directly into the multi-channel SDR system. This combination CRPA and SDR system was characterized in an anechoic chamber environment to closely replicate the fielded antenna/receiver system. This combined CRPA and SDR system calibration method configuration can provide multi-antenna element characterization and calibration measurements that can be used to remove carrier and code phase biases caused by the antenna elements and receiver front-end components for down-stream adaptive signal processing algorithms. For verification, the calibration data produced by the CRPA/SDR system configuration will be compared with calibration data produced using a traditional CRPA anechoic chamber test approach where each element of the array is characterized one at a time with a traditional antenna test approach.

Committee: Chris G. Bartone PhD (Advisor); Sanjeev Gunawardena PhD (Committee Member); Michael Braasch PhD (Committee Member); David C. Ingram PhD (Committee Member) Subjects: Aerospace Engineering; Electrical Engineering