Techniques for Radio Detection of Ultra-High Energy Cosmic Rays

Radio signals emitted from cosmic ray air showers can be used as a new technique for the detection of ultra-high energetic cosmic rays or neutrinos at energies above 10¹⁸ eV. To apply this technique for the detection of air showers, cost effective new antennas and on-line self-trigger systems have to be developed. In large-scale detector arrays an everywhere radio quiet region is rarely available. Therefore, a self-trigger for each radio station with effective suppression of radio interferences and transients is necessary. A FPGA based self-trigger was developed with the help of externally triggered data. A logarithmic-periodic dipole antenna was used first, but a simple crossed polarized small aperiodic loaded loop antenna turned out to be more robust and cost effective. We present studies of antenna design, analog electronics, trigger, and system design.