An application of active frequency selective surface to reconfigurable antenna technology

This paper illustrates the use of active frequency selective surfaces (FSS) in reconfigurable antennas. A patch-form dual-polarized tunable FSS is adapted for use as an active artificial magnetic conductor (AMC). As with the tunable FSS, the active AMC offers independent tuning capability of the reflection phases for two polarisations of incident EM waves. By combining the AMC with a wideband coplanar waveguide fed monopole antenna, circularly polarisation (CP) capability is realized at any frequency over the 1.15-1.60 GHz band. Furthermore, the CP state can be switched between left hand CP and right hand CP, by simply interchanging the capacitances of varactors controlling the reflection phases of the two orthogonal polarised waves. The antenna covers the frequency bands of all operational and in-preparation satellite navigation systems, including GPS, GLONASS, Beidou and Galileo. polarization reconfigurable circular polarized (CP) antenna using active artificial ground (AG) structure.