Thermally Beam-Direction- and Beamwidth-Switchable Monopole Antenna Using Origami Reflectors With Smart Shape Memory Polymer Hinges

This letter presents a thermally reconfigurable antenna with beam-direction- and beamwidth-switching capability using origami reflectors with smart shape memory polymer (SMP) hinges. The proposed antenna consists of a single monopole antenna with four origami reflectors. We employ SMP hinges to actuate the origami reflectors. When all origami reflectors are unfolded on the ground plane (Mode I), the monopole antenna exhibits omnidirectional radiation because the reflectors operate as dummies. When two origami reflectors are folded perpendicular to the ground plane, forming a corner reflector (Mode II), the proposed antenna operates as a directional antenna. Beam direction can be switched to 45 degrees, 135 degrees, 225 degrees, and 315 degrees by actuating various origami reflector pairs, with increased peak gain from 4.5 dBi (Mode I) to 11 dBi (Mode II). When one origami reflector is folded perpendicular to the ground plane (Mode III), the 3 dB beamwidth increases from 52 degrees (Mode II) to 140 degrees (Mode III). Beam direction of Mode III can also be switched through 0 degrees, 90 degrees, 180 degrees, and 270 degrees by actuating each origami reflector. The proposed antenna performance was successfully demonstrated from electromagnetic simulation and measurement.