Sizing Photovoltaic Harvesters for Energy-Neutral UWB Sensors in Space

Kurzfassung

Impulse radio ultra-wideband (IR-UWB) radios suit intra-spacecraft sensor networks through their multipath robustness and precise ranging capability, but the high peak currents of commercial transceivers strain the small photovoltaic harvesters and supercapacitor buffers practical in space, where lithium cells are poorly suited to the often unconditioned thermal envelope. We derive a temperature aware loss model for energy-neutral UWB nodes that provides a single design equation for the minimum photovoltaic area AP V,min(D, Ee, T). Calculation requires the dominant standing loss, supercapacitor self discharge, which we measure to rise ~2.6× between 25 C and 50 C. The resulting sizing curves show a plateau dominated by leakage current and a slope defined by the energy per transmit burst. For a cadence of one packet per minute under 0.6 W m-2, an ADP5091/DW3000 based prototype`s 10.66 cm2 cell is able to sustain operation at 25 C with ~16 % margin but falls ~25 % short at 50 C, showing how strongly temperature drives harvester sizing.