A Near to Far Transformation using Spherical Expansions Phase 1: Verification on Simulated Antennas
Space and Naval Warfare Systems Center Pacific San Diego United States
Pagination or Media Count:
Tapan Sarkar wrote a substantial technical paper on a transformation mapping an antennas near-field into its far field. A numerical implementation of Sarkars near-to-far transformation is assessed in this report. This report assesses this near-to-far implementation on the following antenna models using only a finite number of near-field samples Analytic antenna models where the near field, far field, and the spherical expansions are computable in closed form, Mini-NEC antenna simulations where the near field, far fields and spherical expansions are numerically computed. The implementation described in this report demonstrates that an antennas far field can be extracted from sampled near field measurements provided the spherical expansion includes a sufficient number of terms and that the near-field samples are sufficiently dense. Phase II of this effort extends the implementation to estimate the number of spherical coefficients necessary to deliver user-specified accuracy in the far field and how noisy the near-field measurements affect the far field approximation.