Analysis of Radiation Pattern of Radar Systems Based on Leaky Coaxial Cables

Theoretical and numerical analyses of the radiation directivity of a guided radar system based on leaky coaxial cable (LCC) are presented both for buried and open installations in clutter conditions. The theoretical model of fields generated by a cable buried in a lossy half-space, such as a sub-soil medium, is introduced to describe the working characteristics of such a leaky coaxial cable. The interactions of two modes, external and internal, which determine the coupling effect between an LCC and the environment, is analysed to predict the overall sensitivity and field pattern of such a radar system. It is shown that the coupling is the measure of the signal accessibility at a given radial distance outside the cable and it is very dependent on the particular installation and environmental aspects. A numerical technique, which describes various kinds of LCC installations and can predict the effective characteristics of a radar system based on an LCC with the required parameters including its directional properties, is proposed to analyze the clutter effects and to optimize the sensitivity of such a radar system both for open and buried installations. The distribution of radiation around the cable is examined numerically for the LCC buried at depth d in a sub-soil medium, as well as for an open installation near different kinds of wall. The radiation pattern of such a radar system across the cable system for both kinds of installation is investigated.