Study of a Planar Spiral Antenna Used in Ground Penetrating Radar System

A planar Archimedean-spiral antenna used in UHF ground penetrating radar system is studied. How to have an effect on frequency property for antenna by changing absorbing structures placed in reflecting cavity is analyzed. According to the analytical result, a new absorbing structure is designed and actual measurement is carried out. Finally, the azimuth pattern and radiation property for antenna is analyzed in frequency domain. Results based on actual measurement show that the change of the azimuth pattern of the antenna designed is not large in concerned frequency band and the polarization property of the antenna is reliable.