Far Field Reconstruction of Antennas via Single-Surface Phaseless
Spherical Near-Field Scans: A Novel Approach based on Dipole Equivalence
Abstract
A novel approach is proposed in this paper to reconstruct the far-field
radiation pattern from the phaseless electric field of an antenna
scanned on a single near-field sphere. It adopts the dipole equivalence
approach to project the near-field electric field into a spherically
distributed array of electric dipoles. We introduce a term representing
the residue from the linearly correlated portion in the least-square
problem associated with the dipole equivalence, namely the linear
correlation residue (LCR). It is demonstrated that by iterative search
to minimize the LCR using the Covariance Matrix Adaptation Evolution
Strategy (CMA-ES), near-field phase distributions can be found
efficiently from the magnitude-only near-field, and the far-field
radiation pattern can be computed. Two representative case studies are
given here to validate the proposed method. Results demonstrate good
agreements between computations and simulations.