Control of the radiation polarization of a system of two coherently excited plane logarithmic spirals

A model is proposed that describes the polarization characteristics of the fields radiated by two coaxially coupled active spirals, with controlled phase shift between them. The polarization control by means of phase change is most effective when the spirals are close to each other and are excited by signals with different amplitudes. This control is possible in a frequency band of the order of an octave, and can be electrical if the phase of the input signal of one of the spirals is changed electrically.