Iteratively Calibrated S11 Thermometry for Microsecond-Scale Intra-Pulse Heating in 96-Well Plates

This paper presents an S11-based thermometry technique that adapts an existing 2.2 GHz PXI pulse-exposure platform for 96-well cell experiments into a calibrated, rapid thermometer. A low-power static run is employed to fit a first-order heating model and iteratively enhance a piecewise-linear S11–temperature mapping, achieving less than 0.1 °C agreement with a fibre-optic probe over a 20 °C range and a thermal time constant of 20–22 seconds. The same calibration is then utilised at MHz sampling, down to 1 kHz, with 100 µs pulses, enabling dual-scale reconstruction of bulk and intra-pulse temperature. Intra-pulse self-heating of approximately 0.2 K per burst, which is completely hidden to the 1–10 Hz fibre probe, is resolved, while phase-slope analysis confirms that residual frequency drift (<0.2 Hz) contributes less than 0.01 °C to the temperature error.