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°, 135°, 225°, and 315° 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° (Mode II) to 140° (Mode III). Beam direction of Mode III can also be switched through 0°, 90°, 180°, and 270° by actuating each origami reflector. The proposed antenna performance was successfully demonstrated from electromagnetic simulation and measurement.