Development of a novel miniaturized LTCC-based wireless pH sensing system

In this work, we present a wireless pH sensing device developed based on low temperature co-fired ceramic (LTCC) substrate. The sensing part includes a signal conditioning circuit and a miniaturized pH sensor based on a Ag/AgCl reference electrode and an Iridium Oxide (IrOx) sensing electrode (1×1 mm
²
). Wireless communication was demonstrated using a commercial wireless module. Our pH sensing system was characterized revealing a super-Nernstian response, with a sensitivity of 71 mV/pH and a limit of detection (LOD) of ~0.054 pH; indicating potential uses in a wide range of applications. The entire miniaturized sensing device (8×15 mm
²
) enables deployments in environmental and food quality monitoring.