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Creating accurate software based models of phased array feeds (PAFs) is one of many steps to successfully integrating PAFs with current and future radio telescopes, which is a goal of many groups around the globe. This thesis characterizes the latest models of a 19 element hexagonal PAF of dipoles used by the BYU radio astronomy research group and presents comparisons of these models with experimental data obtained using a prototype array. Experiments were performed at the NRAO site in Green Bank, West Virginia, and utilized the outdoor antenna test range and 20 meter radio telescope. Accurate modeling of the PAF requires modeling the signal and noise characteristics of the array, which is a computationally large problem. It also requires accurate modeling of the noise contribution of the receivers connected to the coupled array, which is something that has only recently been understood. The modeled and measured element receive patterns, array impedance matrix, signal and noise correlation matrices, and efficiencies and sensitivities of the PAF are compared and promising levels of agreement are shown. Modeled sensitivity is 30 to 46% larger than measured.

As the need for more bandwidth increases, satellite communication (SatCom) terminals are forced to climb higher in frequency. Higher frequency means greater propagation losses, and so antenna gain and sensitivity have to increase. The higher the gain, the more difficult it is to point the antenna. To make matters even more challenging, consumers are requesting satellite links in harsher environments and on moving vehicle and planes. In order to meet today's challenges and improve on dish feeds, research is ongoing to replace fixed-beam feedhorns with smaller, cheaper, and lighter PCB based antennas and to develop low-cost electronically steered array feeds (ESAF). ESAFs will not only improve the signal link, but they will also aid in pointing the antenna and then tracking the satellite independent of movement. Here is presented some of the first planar antenna dish feeds developed by the Brigham Young University's SatCom Group. Included are the simulation and test procedures to determine if they are viable for SatCom use. The results show that these antennas make significant advancements in efficiencies and prove a path forward to a feedhorn replacement. Several planar designs are presented, each with a unique solution to meet all the requirements for a dish feed. Also presented is the first low-cost ESAFs developed to give commercial SatCom an electronically steerable dish. None of the designed hardware requires a redesign of current modems and receiver boxes. The research looks at keeping costs low by minimizing the required electronics. This further led to researching the limits on how simple the electronics could be. The ESAF doubled the visible area of the dish and successfully acquired and tracked a satellite as the dish moved. The ESAF also demonstrates a path forward to increase the steerable range and improve pointing and tracking.

This dissertation explores the expansion of the Electrically Steerable Parasitic Array Radiator (ESPAR) technology to arrays using microstrip patch elements. Scanning arrays of two and three closely-coupled rectangular patch elements are presented, which incorporate no phase shifters. These arrays achieve directive radiation patterns and scanning of up to 26° with maintained impedance match. The scanning is effected by tunable reactive loads which are used to control the mutual coupling between the elements, as well as additional loads which compensate to maintain the appropriate resonant frequency. The design incorporates theoretical analysis of the system of coupled antennas with full-wave simulation. A prototype of the threeelement array at 1 GHz is fabricated and measured to exhibit a maximum gain of 7.4 dBi with an efficiency of 79.1%. Further, the microstrip ESPAR is thoroughly compared to uniformlyilluminated arrays of similar size. To satisfy the need for higher directivity antennas with inexpensive electronic scanning, the microstrip ESPAR is then integrated as a subarray. The three-element subcell fabrication is simplified to a single layer with an inverted-Y groove in the ground plane, allowing for DC biasing without the need for the radial biasing stubs or tuning stubs found in the two-layer design. The 1 GHz ESPAR array employs a corporate feed network consisting of a Wilkinson power divider with switchable delay line phase shifts, ring hybrid couplers, and achieves a gain of 12.1 dBi at boresight with ±20° scanning and low side lobes. This array successfully illustrates the cost savings associated with ESPAR subarray scanning and the associated reduction in required number of phase shifters in the RF front end.

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Yes / In the equivalent frequency-based model, the antenna array gain is utilised to characterise the frequency response of the beam squint effect generated by the antenna array. This impact is considered for a wide range of uniform linear array (ULA) and uniform planar array (UPA) designs, including those with and without tapering configurations. For a closer look at how the frequency response of the array adapts to the variations in the incidence angle of the signal, the bandwidth of the spectrum is varied and investigated. To study this effect, we have considered using the gain array response as an equivalent channel model in our approach. Beam squinting caused by distortion in the frequency response gain can be verified by one of two equalisers: a zero-forcing (ZF) equaliser or a minimum mean square error (MMSE) equaliser. Different cases with their analysis and results are studied and compared in terms of coded and uncoded modulations. / This work was supported in part by the Satellite Network of Experts V under Contract 4000130962/20/NL/NL/FE, and in part by the Innovation Program under Grant H2020-MSCA-ITN-2016 SECRET-722424.

Microphone arrays are becoming increasingly integrated into every facet of life. From sonar to gunshot detection systems to hearing aids, the performance of each system is enhanced when multi-sensor processing is implemented in lieu of single sensor processing. Head mounted microphone arrays have a broad spectrum of uses that follow the rigorous demands of human hearing. From noise cancellation to focused listening, from localization to classification of sound sources, any and all attributes of human hearing may be augmented through the use of microphone arrays and signal processing algorithms. Placing a set of headphones on a human provides several desirable features such as hearing protection, control over the acoustic environment (via headphone speakers), and a means of communication. The shortcoming of headphones is the complete occlusion of the pinnae (the ears), disrupting auditory cues utilized by humans for sound localization. This thesis presents the underlying theory in designing microphone arrays placed on diffracting bodies, specifically the human head. A progression from simple to complex geometries chronicles the effect of diffracting structures on array manifold matrices. Experimental results validate theoretical and computational models showing that arrays mounted on diffracting structures provide better beamforming and localization performance than arrays mounted in the free field. Data independent, statistically optimal, and adaptive beamforming methods are presented to cover a broad range of goals present in array applications. A framework is developed to determine the performance potential of microphone array designs regardless of geometric complexity. Directivity index, white noise gain, and singular value decomposition are all utilized as performance metrics for array comparisons. The biological basis for human hearing is presented as a fundamental attribute of headset array optimization methods. A method for optimizing microphone locations for the purpose of the recreation of HRTFs is presented, allowing transparent hearing (also called natural hearing restoration) to be performed. Results of psychoacoustic testing with a prototype headset array are presented and examined. Subjective testing shows statistically significant improvements over occluded localization when equipped with this new transparent hearing system prototype. / Ph. D.

The use of phased array antennas in present day technology is limited, primarily due to the extremely high cost of implementation. This cost is contributed to the expense of phase shifters, which are the traditional method of beam steering in phased arrays. The need to alleviate this cost and avail the technology for commercial use necessitates study into alternative mechanisms for accomplishing beam steering. To this effect, this research is an exploration of one such mechanism. To characterize mutual coupling between microstrip patch antennas and explore its practicality as a feed mechanism, it is necessary to understand the factors controlling the phenomenon. A parametric study of the spacing between patch antennas and the consequent coupling is presented, the results of which are discussed in detail. further study into bandwidth extension and steer controlling techniques are also shown, with discussion on the practicality and future of the mechanism as a candidate for widespread application.

Field-programmable analog arrays (FPAAs) provide a method for rapidly prototyping analog systems. Currently available commercial and academic FPAAs are typically based on operational amplifiers (or other similar analog primitives) with only a few computational elements per chip. While their specific architectures vary, their small sizes and often restrictive interconnect designs leave current FPAAs limited in functionality, flexibility, and usefulness. Recent advances in the area of floating-gate transistors have led to an analog technology that is very small, accurately programmable, and extremely low in power consumption. By leveraging the advantages of floating-gate devices, a large-scale FPAA is designed that dramatically advances the current state of the art in terms of size, functionality, and flexibility. A large-scale FPAA is used as part of a mixed-signal prototyping platform to demonstrate the viability and benefits of cooperative analog/digital signal processing. This work serves as a roadmap for future FPAA research. While current FPAAs can be compared with the small, relatively limited, digital, programmable logic devices (PLDs) of the 1970s and 1980s, the floating-gate FPAAs introduced here are the first step in enabling FPAAs to support large-scale, full-system prototyping of analog designs similar to modern FPGAs.