Penetradar’s IRIS Vehicle installed with a multi-frequency non-contacting horn antenna array.

One of the main applications of Ground Penetrating Radar is for determining pavement layer thickness. Penetradar Corporation incorporates a multi-frequency antenna array in pavement layer thickness surveys to aid in the analysis by providing detailed GPR data at various depths.

The pavement depth profile plot below shows the advantage of the multi-frequency antenna array and its ability to measure thickness of both very thin pavement layers and layers at greater depths.

Penetradar’s ColorPro software showing GPR data of three pavement layers (bituminous, concrete, aggregate base) by using a multi-frequency antenna array

The depth profile plot above shows the same pavement section evaluated by three different antennas in the array. The 2 GHz antenna provides a higher resolution at shallower depths and is optimal in measuring thin bituminous surface layers (Layer 1) and multiple lifts in this layer. The 1GHz antenna is a compromise between resolution and depth, while the 500 MHz antenna is better suited for greater depths of penetration and provides superior results when measuring the aggregate base (Layer 3). The three antenna array provides a unique capability that cannot be achieved with a single frequency antenna.

When the 1 GHz antenna is combined with the 2 GHz and 500 MHz non-contacting horn antennas, GPR data at various depths in pavement can be resolved with great detail. This is critical in analysis for maintaining accuracy in determining pavement layer thicknesses.