Abstract:

Due to size, computational and power limitations an integrated nanosensor device needs to be redesigned with a limited number of components. A sensorless event detection node can overcome these limitations where such node can be powered using energy harvested from various events. The harvested energy could also be a significant factor for events detection without using any sensors. This study presents a detailed description of a sensorless event detection node which consists of two components — an energy harvester and a pulse generator. We discuss the state of the art configurations for these two components. However, due to the low complexity of the nanoscale device, the pulse generator should be kept simple. We, therefore, theoretically investigate different approaches for the pulse generator to generate Surface Plasmon Polaritons (SPPs) which reasonably resemble femtoseconds long pulses in graphene. Based on our analysis, we find that SPPs can be excited using a near-field excitation method for the THz band which is simple and can produce Electromagnetic (EM) radiation with a wide range of high wavenumber. Hence, the coupling condition can be easily satisfied and consequently, the SPP wave can be excited. However, such method excites SPPs locally, which requires improvement in practice. Thus we numerically investigate how operating frequency, the doping amount of graphene and the properties of the evanescent source affect the plasmon resonance of SPPs. We also studied different evanescent sources such as electric dipole, and hexapole, and find that the former provides better SPP resonance. We also observe that through fine-tuning of the chemical potential, frequency and source phase angle, higher amplitude SPPs can be excited on graphene surface in the THz band. The proposed model can be a good candidate for a low-complexity realization of a THz pulse generator in self-powered sensorless events detection node.