Investigation of the scattering field under the low-frequency resonance conditions of screw helices

Abstract

The frequency-selective properties of small screw helical coils are investigated. It is shown that, in a frequency band of 2–4 GHz, such coils have two resonances. The scattering patterns of helical coils are measured in the E and H planes. It is found that, at the zeroth-order resonance, a coil scatters a circularly polarized field with the maximum in the plane perpendicular to its longitudinal axis and that, at the frequency of the first resonance, the maximum of the scattered field is oriented along the longitudinal axis of the coil.