Transformation of the polarization of electromagnetic waves by helical radiators

Transformation of the polarization of an electromagnetic wave by a 2D array of double-turn metal helices is investigated both theoretically and experimentally. Electric and magnetic moments induced in an isolated helix by an incident linearly polarized wave are determined. A universal relationship between the projections of the induced moments onto the axis of a helix is derived. The helix parameters that are optimal for radiation of a circularly polarized wave are calculated. A 2D array composed of double-turn helical radiators with optimum parameters is manufactured. Experimental verification of the obtained theoretical results is performed.