CALALAULATION OF RADIO LOSS IN FOREST ENVIRONMENTS
| Autor: | Yu-Yui Kuo, 郭永裕 |
|---|---|
| Rok vydání: | 2000 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 88 In this thesis, the study is focused on the calculation of radio loss in forest environments. Quantitatively detailed knowledge of radio loss in forest is an essential component in designing the communication link and developing microwave remote sensor. However, the study and understanding of radio wave propagation in forest have been handicapped by the complexity of wooded structures. In this thesis, an optimum four-layered forest model is proposed for the calculation of radio loss in forest environments. This optimum four-layered forest model is obtained by modifying a commonly used model consisting of homogeneous and isotropic dielectric layers placed over a conducting flat earth. In the optimum four-layered forest model, the first layer is the semi-infinite free-space, the second layer represents the forest canopy consisting of leaves and branches, the third layer models the trunks of the forest, and the last layer is the semi-infinite flat ground plane. The dielectric constant of trunks is obtained from published papers and the equivalent dielectric constant of the canopy is calculated by the equivalent dielectric constant technique. After comparing the numerical results with those obtained from measurement data, it is found that there is a good agreement between the numerical results and measurement data. Based on the numerical results, an empirical formula is developed by using the least square curve-fitting method. This empirical formula is suitable for the calculations of radio loss in forest in the frequency range from 1 to 100 GHz. This formula also provides a simple, fast, accurate, and inexpensive method for calculating the radio loss in forest. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|