Novel Antenna Designs for a Compact Ground Penetrating Radar Systems

Abstract

High-speed miniaturized air-coupled Ground Penetrating Radar (GPR) array systems operated at traffic speeds require compact highly-integrated ultra-wide band (UWB) antennas for applications such as pavement or bridge deck inspections. æThree specific UWB antenna design are described, discussed, and tested: a rounded bowtie, a slotted bowtie, and a Vivaldi antenna. æThe size is kept compact for those antennas, among which the smallest possesses a dimension of 11 cm X 8 cm X 5 cm, and radiation gain of 6 dB for operation in the 1.5 _ 3.5 GHz frequency band to be compliant with FCC limits. æThe antenna design methodology is based on an iterative technique where the radar system electronics are used as baseline target goals for evaluating the antenna performance. æTherefore, the radar front ends matching, as well as the pulse behavior are considered when designing the antennas and optimizing for maximum power transfer and reduced ringing. æThe three UWB antennas were tested with the latest GPR prototype which has an extremely low profile and simple direct connections to the board. æIn-field measurements for the antennas, together with the GPR system were performed, successfully detecting buried rebar in a sand box. æExperiments demonstrated that the radar and the antenna operating frequencies are directly compatible with current bridge deck and pavement GPR applications and methodologies. æThe specifications of the designed low-profile UWB antennas also make them ideal candidates for the air-coupled under-vehicle GPR system applications.