Dual-band, dual-circularly polarised antenna element

A dual-band element that operates with dual-circular polarisation in two separate industrial, scientific and medical bands is presented. The design that is based on concentric square slot/shorted-ring configuration is realisable in cost-effective printed circuit board technology making it attractive for low-cost personal communications devices. The antenna element provides a flexible topology that allows for convenient, independent control of the polarisation and impedance bandwidth of two distinct frequency bands with no fundamental limitation on the ratio between the high- and low-band frequency ranges. The topology of this element is presented, and the antenna concept is validated via simulated and measured results.