Mobile phones, tablets, and other portable devices are prone to failure caused by small defects in their complex electronics that can result from regular use. An innovation provides robust protection against circuitry damage that affects signal transmission.
Particular properties of matter (such as electrical conductivity) can be preserved in certain materials, despite continuous changes in the matter's form or shape. This concept is associated with topology — a branch of mathematics that studies the properties of space that are preserved under continuous deformations. The innovation showed that the science of topology can be used to facilitate robust electromagnetic-wave propagation in electronics and circuit components. In addition, the inherent robustness associated with these topological phenomena can be self-induced by the signal traveling in the circuit, and this robustness can be achieved using suitably tailored nonlinearities in circuit arrays.
Nonlinear resonators were used to mold a band-diagram of the circuit array. The array was designed so that a change in signal intensity could induce a change in the band diagram's topology. For low signal intensities, the electronic circuit was designed to support a trivial topology, and therefore provide no protection from defects. In this case, as defects were introduced into the array, the signal transmission and the functionality of the circuit were negatively affected.
As the voltage was increased beyond a specific threshold, however, the band-diagram's topology was automatically modified, and the signal transmission was not impeded by arbitrary defects introduced across the circuit array. This provided direct evidence of a topological transition in the circuitry that translated into a self-induced robustness against defects and disorder.
As soon as the higher-voltage signal was applied, the system reconfigured itself, inducing a topology that propagated across the entire chain of resonators, allowing the signal to transmit without any problem. Because the system is nonlinear, it is able to undergo an unusual transition that makes signal transmission robust, even when there are defects or damage to the circuitry.
Similar ideas can be applied to nonlinear optical circuits, and extended to two-and three-dimensional nonlinear meta-materials.