2維及3維VHF/UHF無線電波在不規則起伏地形之通道模型建構及研究

Abstract

本研究將發展2維及3維VHF/UHF無線電波適應環境傳播模式，探討VHF/UHF電波在不規則起伏地形環境中之傳播機制。這些傳播模式是利用均勻繞射理論及物理光學法，並結合數位電子地形圖以計算起伏地形環境之繞射場及散射場。藉由量測竹子山發射的數位及類比電視信號以驗證模式計算結果。2維傳播模式的預估誤差之平均值及標準差分別為-0.5dB及6.1dB，而3維傳播模式之場強預估準確度則略優於2維傳播模式，並能更有效的計算通道脈衝響應。

In this paper, a two-dimensional and a three-dimensional site-specific propagation models have been developed to investigate propagation mechanisms in irregular terrain environment. The models are conducted based on theories of uniform diffraction and physical optics. They have been combined with digitized topographic map of Taiwan to compute the field strength. The computed result is verified by the measurement data of signals with the transmitting antenna location on Chu-Zue mountain. Mean and standard deviation of prediction errors are equal to -0.5dB and 6.1dB respectively, for the 2-D model. The 3-D model only has little better performance than the 2-D model in estimating signal field strength, but it is more effective than the 2-D model in computing the channel impulse response.