Noise Analysis in Screen-Printed Carbon-Black Resistive Gauges Towards Strain Sensors

We investigate the noise performance of screen-printed carbon-black elastoresistors. Our work focuses on the quality of the printed resistors as devices. The noise power spectral density is measured for seven target bias currents on fifteen resistors obtained from printing at three different speeds, each providing a set of five resistors with different lengths and hence resistances. The process variations resulting from the different printing speeds ensure a large sample diversity, with inhomogeneities inherent to printed polymer material. The contributions of thermal noise and lowfrequency (1/f) noise have been extracted separately. The physical origin of the 1/f noise is discussed based on previously published models for carbon resistors. The trends of the 1/f noise intensity against sample properties are consistent with former works and hence exclude abnormal process-induced material inhomogeneities and defect distributions. We assess the impact of the printed ink resistance and bias current on the total noise power for the three different printing speeds. We finally highlight that signal-to-noise ratios (SNR) over 100 dB can be achieved for these elastoresistors in practical conditions with interesting trade-offs regarding size and power consumption.