COMPUTER MODEL FOR THE DESIGN OF A VHF ANTENNA TEST RANGE

摘要

In practice, accurate measurement of VHF antenna radiation patterns can be difficult to achieve due to the presence of large multi-path reflections in the test range. Special range geometries and source arrangements have been devised over the years to mitigate the measurement errors produced by test range multi-path. In this paper, we describe a computer model designed to accurately control the influence of ground path illumination and, in turn, reduce quiet-zone amplitude and phase variation. We use an array of dipoles as our transmit source. Using an electromagnetic image-method approach, we fully characterize the test range by calculating the transfer function between the element excitations and the quiet-zone electric field. We then use this transfer function to solve for the element excitations that produce minimal amplitude and phase variation in the quiet zone. Our simulated results show that when the number and locations of the array elements are varied, reduced quiet-zone amplitude and phase variation is achievable for several range geometries.