Multiband irradiator of spiral coils with outputs for each frequency band

This paper describes a way of designing a circularly polarized antenna consisting of regular spiral coil irradiators tuned to different frequency bands and aligned one inside another. In so doing, the required directionality characteristics are provided for each frequency band. The analytical relationship between currents in coils of aligned spirals is presented. Practical implementation and a comparison between analytical and experimental results are also demonstrated.