Millimeter-wave Pattern Reconfigurable Vivaldi Antenna Using Tunable Resistor Based on Graphene

In this communication, a millimeter-wave (MMW) pattern reconfigurable Vivaldi antenna utilizing graphene-based tunable resistor is proposed. First, a modified Vivaldi antenna with high front-to-back ratio is achieved by equal proportion slotting on the ground patch. Then, a pattern reconfigurable antenna consisting of a pair of back-to-back modified Vivaldi antennas with two graphene nanoplate pads symmetrically loaded on the feed line is proposed to realize dynamical manipulation of gain. By applying bias voltage from 0 to 4 V, the resistance of the graphene pad can be gradually reduced from 200 to $20~\Omega $ . Two slots located on the ground allow two graphene pads to be dc interruption for independent resistance control. By varying the resistance of two graphene pads, the radiation pattern of Vivaldi antenna can be manipulated from two opposite beams to a single beam. Finally, a prototype antenna centering at 30 GHz with a bandwidth of 16.6% is fabricated and measured, which realizes reconfigurable radiation beams at 90° and/or 270° with three states.