Use of an active retrodirective antenna array as a multipath sensor

The use of an active retrodirective antenna as an indicator of multipath propagation effects is investigated by the authors. It is shown that the flat azimuthal gain response normally associated with a retrodirective antenna array can be significantly modified by the presence of multipath signals. These signals act as secondary sources impinging on the retrodirective antenna array and give rise to amplitude perturbations in its azimuthal gain response. Using a retrodirective antenna array, the relative amplitude and phase components for the multipath signals can be recovered. In this way, the retrodirective antenna can be used as a low-cost multipath sensor.