垂直大气湍流影响下的微波传播损耗变化研究

Study on Variation of Microwave Propagation under Influence of Vertical Atmospheric Turbulence

微波在自由大气中传输,由于湍流的作用而产生幅度、相位起伏,从而导致传播特性的变化。采用C_n^2估算模型和湍流外尺度的垂直模型,结合常规气象参数,建立垂直分布湍流模型,分析了不同外尺度模型下微波折射率结构参数的变化情况;通过PE模型结合一维折射率谱,建立垂直高度分布的湍流影响下的电波传播损耗变化模型。经仿真分析得到:湍流外尺度随着高度的增加而增加;在低空范围,微波折射率结构参数随着外尺度的增加而减小,电波传播损耗随着传输高度的增加而减弱;在中高空范围,湍流对微波传输的影响又增大,传输损耗也变大。垂直湍流下的微波传播损耗建模对于高空微波传输研究有实际意义。

Due to the influence of turbulence, the amplitude and phase of microwave fluctuate in free atmosphere, which changes the propagation characteristics of microwave. Based on the estimation model of Cn2, vertical model of turbulent external scale and conventional meteorological parameters, a vertical distribution turbulence model was es- tablished. The changes of the microwave refractive index structure parameters under different external scale models were analyzed. Combined the PE model with one-dimensional refractive index spectrum, a wavelet propagation loss model with vertical height distribution under the influence of turbulence was established. The simulation results show that the turbulence scale increases with the increase of the height; In the low-altitude, the structure index of the mi- crowave refractive index decreases with the increase of the external scale, and the wave propagation loss decreases with the increase of the transmission height; In the middle and high altitude, the influence of turbulence on micro- wave transmission increases and transmission loss increases. The microwave propagation loss modeling under vertical turbulence has practical significance for the study of high-altitude microwave transmission.