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- Creators: Barrett, The Honors College
- Member of: Theses and Dissertations
As the demand for higher computing speeds increases as modern technology develops, so must the complexity of the processors and connections within these devices. Unfortunately, modern wired connections will not be able to sustain the demands several years into the future due to the physical limitations of the connection mediums as well as the limit of space inside a processor or computer chip. Wireless connections serve as a viable alternative to wired connections due to their ability to handle parallel communications far better than wired communications and their ability to handle much higher data rates, as well as their tendency to take up little space. However, electromagnetic wave propagation inside of a closed conductive environment is difficult due to the effects of scattering and multipath, as these waves reflect off of the conductive surfaces and lead to a very cluttered signal at the receiver due to destructive interference. This project aims to solve this issue by introducing a reconfigurable metasurface in the form of a 4x4 patch antenna reflectarray. This device utilizes the resistance and capacitance of PIN Diodes to alter the resonant frequency of each of the patch antennas on the device to alter the propagation behavior of incident electromagnetic waves, allowing for a less scattered signal to reach the receiver. After designing and testing the efficiency of this device, an optimization process will be created to find the optimal PIN Diode configuration (On and Off) so that the best Channel Impulse Response (CIR) can be found, which represents the highest communication efficiency. Once this process is completed, the device can operate at the optimal configuration to perform a specific function at a specific location.
This creative project is a part of the work being done as a Senior Design Project in which an autonomous solar charge controller is being developed. The goal of this project is to design and build a prototype of an autonomous solar charge controller that can work independently of the power grid. This solar charge controller is being built for a community in Monument Valley, Arizona who live off grid. The controller is designed to step down power supplied by an array of solar panels to charge a 48V battery and supply power to an inverter. The charge controller can implement MPPT (Maximum Power Point Tracking) to charge the battery and power the inverter, it also is capable of disconnecting from the battery when the battery is fully charged and reconnecting when it detects that the battery has discharged. The charge controller can also switch from supplying power to the inverter from the panel to supplying power from the battery at low sun or night. These capabilities are not found in solar charge controllers that are on the market. This project aims to achieve all these capabilities and provide a solution for the problems being faced by the current solar charge controller
The coffee cup system can be simplified and modeled by a cart-and-pendulum system. Bazzi et al. and Maurice et al. present two different cart-and-pendulum systems to represent the coffee cup system [1],[2]. The purpose of this project was to build upon these systems and to gain a better understanding of the coffee cup system and to determine where chaos existed within the system. The honors thesis team first worked with their senior design group to develop a mathematical model for the cart-and-pendulum system based on the Bazzi and Maurice papers [1],[2]. This system was analyzed and then built upon by the honors thesis team to build a cart-and-two-pendulum model to represent the coffee cup system more accurately.
Analysis of the single pendulum model showed that there exists a low frequency region where the pendulum and the cart remain in phase with each other and a high frequency region where the cart and pendulum have a π phase difference between them. The transition point of the low and high frequency region is determined by the resonant frequency of the pendulum. The analysis of the two-pendulum system also confirmed this result and revealed that differences in length between the pendulum cause the pendulums to transition to the high frequency regions at separate frequency. The pendulums have different resonance frequencies and transition into the high frequency region based on their own resonant frequency. This causes a range of frequencies where the pendulums are out of phase from each other. After both pendulums have transitioned, they remain in phase with each other and out of phase from the cart.
However, if the length of the pendulum is decreased too much, the system starts to exhibit chaotic behavior. The short pendulum starts to act in a chaotic manner and the phase relationship between the pendulums and the carts is no longer maintained. Since the pendulum length represents the distance between the particle of coffee and the top of the cup, this implies that coffee near the top of the cup would cause the system to act chaotically. Further analysis would be needed to determine the reason why the length affects the system in this way.