| 摘要: | 摘要 最近,對於室內無線網路與個人通訊系統而言,為了能夠提昇無線傳輸的資料率,傳輸更多的多媒體訊,進而走向更高的操作頻段(5.3GHz),此頻段能提供比2.4GHz頻段較大的頻寬與避免其它操作在2.4GHz頻段的通訊系統互相干擾。 然而,較高的操作頻段與資料率也會增加多重路徑的問題,因此,無線電波在室內傳播通道特性的研究成為重要的課題。 本研究中,我們量測並分析室內環境的電波傳播特性,我們使用網路分析儀同時產生和量測寬頻信號在頻域上的資料,再藉由傅利葉轉換,我們可以分析脈衝信號在時域上的資訊。此外,在基地台之天線使用方面,針對不同的量測環境使用不同性質的天線,由於天線場型會影響電波傳播的特性,我們必須考量其影響因素以找出在這量測環境中,基地台位置有最佳的涵蓋率與通訊品質。且在此論文中,在不同發射端天線高度與使用單極天線的情況下,我們量測室內寬頻無線電波的通道特性。最後,為了更好的描述室內建物材質的介電特性,我們使用自由空間技術來量測建物材質的穿透係數與反射係數,並藉由厚板模型來計算建物材質的相對常數與導電率。 Abstract There is an increasing demand for high data rate wireless transmission for indoor radio network and personal communication network systems. The 5.3GHz frequency band is promising to support such applications since it offers wide bandwidths. However, higher operating frequencies and higher date rates result in increased multipath problem. Consequently, the radio propagation characteristic for indoor environment becomes an important research topic. This thesis reports the measurement and analysis of wideband radio channel in indoor propagation environment. The network analyzer, HP 8510C is used to measure the wideband signal propagation synchronously in frequency domain. By using FFT, the corresponding impulse signal in time domain is then analyzed. Because the antenna pattern used at the base station affects the propagation characteristic , we must consider all related factors in order to find out best coverage performance of the base station location in the measurement environment. In this thesis we reported measurements on wideband indoor channel characterization based on monopole antennas with different transmitter heights. Finally, in order to get accurate predications, a good description of the electromagnetic properties of the obstacles present in the environment is needed. A experiment was made in order to characterize the electromagnetic parameters of the building materials. Transmission and reflection coefficients were measured using the free-space technique. The slab model was used to estimate the permittivity and conductivity. |
