时域近场测量的间接频域算法和直接时域算法研究

时域近远场变换是时域近场天线测量的关键技术。本文对时域近远场变换的间接频域算法和直接时域算法进行了数值模拟和分析。针对开口矩形波导天线的时域近场测量 ,选取时空采样参数和内插公式 ,用两种算法计算时域远场方向图 ,分析周期性、时域混叠问题和扫描面截断效应 ,在相互比较和验证的基础上 ,指出两者的优、缺点及适用的情况。

Study of Time-Domain Near-Field Measurements by Indirect Frequency-Domain Algorithm and Direct Time-Domain Algorithm

The time-domain transformation from near-field to far-field is the key technique for time-domain near-field antenna measurements. The indirect frequency-domain algorithm and the direct time-domain algorithm are analyzed through numerical simulations. A detailed simulation of time-domain near-field measurements of an open-ended rectangular waveguide is taken by computing the time-domain far-field patterns with the spatial-time sampling parameters selected and the interpolation expressions given. The periodic characteristics, the time-domain aliasing and the truncated scan plane effect are analyzed. Based on the mutual comparison and verification, their advantages and disadvantages are pointed out as well as the situations to which they are applicable.