Link budget analysis for secure thermal infrared communications using engineered blackbody radiation

The `THz Torch' concept was recently introduced as an ultra-low cost means of providing secure short-range wireless communications in the thermal infrared spectral range (10-100 THz). This technology exploits engineered blackbody radiation, by partitioning thermally-generated spectral noise power into pre-defined frequency channels; the energy in each channel is then independently pulsed modulated and transmitted. This technology can be further enhanced by multiplexing schemes, e.g. frequency division multiplexing (FDM) and frequency-hopping spread-spectrum (FHSS). In this paper, the end-to-end link budget analysis for a 4-channel `THz Torch' working demonstrator, operating over a short transmission range of 1 cm, is given for the first time. Mathematical modelling of the end-to-end wireless link is presented. In the analysis, different bias points for the source are considered and the corresponding RMS output voltages at the receivers are calculated. The predicted results show the capability for each channel, and will serve as a guide for further improving the overall performance of this multi-channel `THz Torch' system.