Neuronlike impulses in a travelling wave structure loaded with resonant tunneling diodes and air bridges

In this paper a coplanar waveguide (CPW) periodically loaded with resonant tunneling diodes (RTDs) and air bridges (AB) is presented as a travelling wave (TW) structure for modelling the FitzHugh-Nagumo (FHN) equation and emulating the behaviour of the nerve axon. Based upon an electrical equivalent circuit, the principle of operation is discussed in the context of a lumped-element circuital model being compared to a distributed structure. The phenomena of wave formation and propagation are studied by computer experiments of the underlying nonlinear ordinary difference-differential equations (ODEs) and that of the approximated model nonlinear partial differential equations (PDEs). A key achievement is that this medium supports stable propagating shock waves (kinks and antikinks) when effects of AB are neglected as well as stable traveling pulses only determined by the parameters of the circuit. As a result, compact electronic circuits with features of real neural systems are developed to be an experimental medium mimicking neural activity and to be applied in ultra-fast signal processing. (paper)