Non-Uniform Warping Sampling for Data Reduction in Planar Array Diagnostics

Abstract

The problem of detecting defective turned-off elements in antenna arrays from near-field measurements is addressed. In particular, the focus here is to reduce the number of measurements in order to positively affect the acquisition time. Such an issue is achieved by adopting the recently developed warping sampling method. Two commonly antenna diagnostics methods, i.e, the Back Transformation Method (BTM) and the Matrix Method (MM), are considered in view of this new sampling strategy and compared to the usual half-wavelength sampling. In particular, in order to identify the fault locations, outcomes returned by BTM and MM undergo a detection step based on a cell-averaging CFAR (CA)-CFAR technique borrowed from the radar literature. It is shown that the warping sampling method provides performance close to the uniform half-wavelength one with a reduced number of data. Numerical simulations are carried out in order to verify the results with different fault layouts and tapered currents. INDEX TERMS Antenna measurements, Sampling methods, Array diagnostics, Inverse imaging, Nonuniform sampling

An Insight into the Warping Spatial Sampling Method in Subsurface Radar Imaging and Its Experimental Validation

“…where it is shown to be much lower than the number of spatial samples required by all other criteria described in the literature when near-field configurations (as for the case at hand) are considered [37][38][39]. Note that all the sampling criteria in the literature refer to a freespace configuration.…”

“…More recently, we progressed in the sampling theory by introducing the so-called warping approach [37,38]. It was shown that this method could consider the spatially varying filtering introduced by the near-field propagator.…”

“…Section 3 is devoted to recalling some literature sampling criteria and presenting the basics of the warping sampling theory. However, we advise the reader that all the theoretical details of this approach can be found in [37][38][39][40]. In Section 4, the scattering experiments are described, and the corresponding reconstructions are reported.…”