A Millimeter-Wave Polarization-Reconfigurable Double-Folded Antenna Array

This letter introduces a double-folded, polarization-reconfigurable, dual-antenna array for millimeter-wave communications. The proposed structure reconfigures its polarization by supporting either left- or right-handed circularly polarized radiation with a maximum realized gain that reaches up to 15.8 dBic for each state. Reconfiguration is achieved through the activation of a single-pole-double-throw switch. A dedicated folded feeding network with a triangular power distribution is designed to achieve the required in-phase power distribution between the ten radiating elements that compose each antenna array. The folded feeding network eliminates the need for a stacked design with integrated vias, which reduces undesired interferences and inductive parasitic effects. The fabricated prototype validates the operation of the proposed reconfigurable structure where a measured axial ratio that is less than 3 dB is achieved between 28.8 and 31.2 GHz with a measured half-power beamwidth of 13 degrees along the direction of maximum radiation.