Dual-Purpose Metasurface for Background Insensitive UWB Tag : (Invited Paper)

A circularly polarised metasurface is proposed in this paper. The design of the surface aims at improving the performance of a hybrid radiating structure made of one dipole and an Archimedean spiral antenna designed on the same surface. The antennas operate in UHF and lower European UWB bands, respectively, and realize a compact single-port antenna for future generation autonomous RFID tags. A High Impedance Surface (HIS) is employed as the ground plane to serve as a Perfect Magnetic Conductor (PMC), with the double purpose to maintain both the circular polarization in the UWB band and the low-profile stack-up, while assuring an insensitive behaviour to the background material.