KU Abstract 2014-Propagation & Recovery of Radio Waves between Dielectric Mediums

Names: Ryan Alvarez, Olathe Northwest High School; Hannah Gibson, Bishop Seabury High School; Jason Irvin, Olathe Northwest High School

Research Teacher Mentor:  James Deane, Ottawa Sr. High School

Research Mentor: Dr. Jordan Hanson, University of Kansas

Institution: The University of Kansas

Purpose:

Detecting radio wave showers is one modern method of studying neutrinos. Our task was to examine the phenomenon of surface waves as they occur at the interface between air and sand. Studying surface waves will allow us to study radio waves of increased longevity. Working with surface waves could allow scientists to study more neutrino interactions, particularly in Antarctica, where current detectors are inserted a considerable distance into the ice in a non-recoverable fashion. Surface waves would be easier to detect and allow detection equipment to be reused.

Method:

A large number of tests were performed using multiple forms of antennae. Each trial tested for the decay of signal power over increments of distance between a transmitting antenna and a receiving one within a sandbox. We began measurements at 20 cm and increased by increments of 10 cm until the signal was no longer discernible from the background noise. Several different tests allow us to identify how the signal was changing naturally. Subsequent tests involved the antenna’s proximity to the sand itself, with one configuration having the antenna above and away from the sand, another with the antenna lightly placed on top, and another with it being partially buried. These distances, in theory, would affect the propagation and recovery of Surface waves, but would have little impact on the regular radio wave travel other than the normal drop in signal strength over distance. Similar tests were done at a fixed distance with a change in the angle of the antennae. From this data we attempted to isolate and extract differences to describe the behavior of surface waves.

Results:

Graphical analysis of the data showed that the regular behavior of the radio waves were proportional to distance quadratically, which is to say that the energy of the wave dissipates exponentially, and can be modeled by Volts/Radius^2. In some of our tests, we observed a much different response. We found that the energy dissipated at a much lower rate, being closer to Volts/Radius, which is consistent with other reports of surface waves. These results were found in the small sandbox during some of the earlier tests of placing the antennae on the very top of the surface, then again partially with an air test at a 90 degree rotation.

Future Testing:

Because the tests that actually demonstrated the effects of surface waves were rare and difficult to repeat, future testing should be devoted to making a more reliable strategy of producing and utilizing these waves focusing on the specific tests that succeeded for us. The purpose of finding them is fulfilled, giving indications of where they are. Future designs can use this information to narrow the search for and develop more precise tactics for surface waves.