Detection of radioactive materials using surface proximity antennas

Summary form only given. The objective of this study is to detect and identify radioactive materials using surface proximity antennas. To do so, we first developed a simulation model of earth as seen in Fig 1a. We have then designed microstrip patch antennas propagating (-z-direction) towards earth surface to understand the effects of earth and buried objects on the antenna performance (Fig. 1b). Various types of objects (pec, radioactive materials, glass, etc.) were placed at different depths and simulations were carried out to detect changes in antenna parameters such as return loss. It was seen that buried objects does affect the antenna performance changing with the type of the object. We have searched for frequencies in the spectrum and considered antenna array systems to increase the detectability of the problem. Figure 2a shows the antenna return loss comparison for three different cases; a) without the object, b) object located right beneath the surface, and c) object located 20cm beneath the surface. In Figure 2b, we present electric field distribution. The hot spot represents the region where the object is located. At the time of the presentation, we will provide antenna design details, and simulation results for various antenna topologies and operating frequencies.