Development of Efficient Waveguide Transmitarray Antenna Design Tool and Improvisation of Their Scan Angle Capability
| Autor: | Siddhartha Panigrahi, 潘西和 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 This project aims to design a simple and efficient simulation tool for waveguide transmitarray antenna. They are a low cost, high gain solution for different long range applications like satellite TV applications, earth remote sensing, solar energy concentrator etc. They provide a very high gain (>20dBi) and a highly directive pattern. As array technique is used to achieve the gain of this magnitude, the number of cell elements for such antennas are very large. To simulate such structures, with large number of elements, using commercial software can be a tedious task as they are time consuming. Also in applications like pattern synthesis where we need to check the antenna pattern frequently as the solutions are often not convex, the commercial simulation software reduces the overall work efficiency. Moreover, for every minor change, the structure should be rebuilt every time. These problems can be overcome by establishing a simplified mathematic model and formulation to estimate the structure, instead of full wave simulation of a complete structure. To calculate the formulation, a mathematical model was first developed to calculate the component of the incident field that is propagated through the unit cell elements or waveguides in this case. Then the total power transferred from the feed to the waveguide was calculated. Finally, a generic radiation equation was derived by calculating the surface current densities for individual cell elements and also for the array. The structure of the array was determined by considering two surfaces of the array and the refractive index of the waveguides as variables. For a single beam case, only one surface was modeled and hence only one source is required. For multi-beam case, two surfaces of the array were modeled using two sources. This case has already been studied by various authors and it has been found that, the scan angle for such system is small. Hence a novel approach of considering refractive index of each waveguide as a third variable has been used. This allows us to put another source in the focal arc on the axis of antenna. This approach had a better scan angle capability than other waveguide array antennas. The radiation equations and the structural parameters are then used to build the waveguide transmitarray simulation tool for different configurations for faster pattern prediction. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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