X-band Holographic Antennas Back Radiation Comparison

It is known that “back” radiation in holographic antenna systems radiation pattern is associated with the choice of a binary approximation of the interference pattern when recording holograms. In this paper, it is shown that this effect can be avoided by using a system of coupled dipoles instead of solid metal in the surface synthesis. The data of both numerical and experimental (in far-field zone for radiation patterns measurements and in near-zone for amplitude distributions) study of X-band flat holographic screens are presented. Numerical peak directivity value for proposed holographic surface topologies is found to be 19.3 dB while for one-layer holographic antenna system based on solid metallization numerical peak directivity value is 16.7 dB. The measured F/B ratio for the proposed design based on coupled dipoles element of two-layer holographic screen at 9.6 GHz is obtained to be -7.65 dB, instead of -2.2 for solid metallization (one-layer design).

I. Introduction

In recent years, there has been a special interest in holographic antennas due to possibility of quick installation and dismantion and ease of manufacture [1]–[3]. The holographic technique is widely used to design leaky-wave antennas [4], various reflecting and passing-through surfaces [5]. For the reason of extensive increase in the number of devices in the new generation communication systems composition various surfaces and lenses with single irradiator or an entire antenna array as a spatial field source are of particular interest [6]- [7].