Design and Assembly of Reconfigurable 3D Radio-Frequency Antennas Based on Mechanically Triggered Switches

Reconfigurable radio frequency (RF) antennas represent a class of antennas whose radiation properties, in particular the working frequency, can be actively tuned to efficiently make use of the crowded frequency spectrum in wireless communications. Researchers have developed several different methods to design and fabricate reconfigurable antennas through use of deformable conducting materials or electrically/optically activated switches. Most of these antennas offer limited performance in terms of the working frequency tunability or the level of flexibility/stretchability. The design of stretchable and reconfigurable 3D RF antennas based on mechanically triggered switches, which leverages controlled compressive buckling to form the devices from patterned 2D precursor structures integrated with an elastomeric substrate, is presented. Theoretical modeling of the buckling process allows a rational design of mechanically triggered switches and reconfigurable antennas with desired activation strains applied to the substrate. Combined experimental and computational studies show that the developed antennas can be tuned to operate at a broad range of discrete frequencies, with a demonstration of the tunability from 2.3 to 7.7 GHz in a dipole-like design. The design concepts and approaches reported herein could have promising applications in wireless bioelectronic devices.