Mode-Switchable Dual-Band OAM Antennas for Integrated Microwave and mm-wave Applications

This paper presents a compact, high-efficiency, mode-switchable dual-band orbital angular momentum (OAM) antenna operating simultaneously at 5.8 and 28 GHz for integrated microwave and millimeter-wave (mm-wave) wireless systems. The proposed design features a single-layer, shared-aperture structure composed of two concentric uniform circular arrays (UCAs), each capable of generating OAM modes with topological charge <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w