Topological Phenomena in Antenna Systems

Topological concepts have found several applications in different branches of physics. As a notable example at microwave frequencies, in this contribution, we focus on the topological properties of phase singularity points of vortex modes, which can be generated by using higher order modes of patch antennas. In particular, we report our recent results on the possibilities offered by structured fields, i.e. the collinear superposition of vortex modes with different topological charges, for designing radiating systems with novel or enhanced functionalities.