ABSTRACT The design method of an unequally spaced array was based on the density tapering in the textbook “Antenna theory” in 1969. The effects on grating lobe reductions were shown by radiation pattern calculations. However, no proof for the achievement of density tapering was shown. In this paper, through direct comparisons of the objective amplitude distribution with electric field distributions by electromagnetic simulation, density tapering is examined. A log-periodic dipole antenna operating from 900MHz to 2500MHz is designed for the array element. The unequally spaced 31-element array antenna is used for calculation. At many kinds of density tapering and many frequencies, calculated electric field distributions in a near-field region of the array antenna agree with the given density tapering distributions. The paper results show that the density tapering is achieved from 900MHz to 2000MHz and the effects of grating lobe reductions are ensured from 900MHz to 2500MHz.

中文翻译：

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通过电磁模拟的电场分布证明不等距阵列的密度锥形概念

摘要 不等距阵列的设计方法是基于 1969 年教科书“天线理论”中的密度锥形。辐射图计算显示了对栅瓣减少的影响。然而，没有显示实现密度递减的证据。在本文中，通过电磁仿真将客观振幅分布与电场分布进行直接比较，研究了密度递减。工作频率为 900MHz 至 2500MHz 的对数周期偶极子天线设计用于阵列元件。不等距31单元阵列天线用于计算。在许多种类的密度锥形和许多频率下，阵列天线近场区域中计算的电场分布与给定的密度锥形分布一致。