Resonant cantilever sensors have been extensively used in mass detection applications. In this paper, a new sensitivity-improving method was proposed by modifying the cross-section shape of the cantilever. With the same dimension, the proposed sensor can offer two to eight times greater sensitivity than traditional rectangular section cantilever sensors. To eliminate the size effect, a dimensionless mathematical model was established for examining the sensitivity improvement brought by adding axial grooves to elastic structures. By utilizing wire-cutting technology, a novel grooved-section cantilever sensor was designed and fabricated, which is comprised of one lead zirconate titanate layer bonding to the grooved cantilever for self-exciting and self-sensing. Experimental results show that the sensitivity of the grooved-cantilever sensor is 37.5 kHz/g with the theoretical sensitivity of 38.1 kHz/g, which is about 120% greater than that of the rectangular section sensor of 17.9 kHz/g with the theoretical sensitivity of 18.2 kHz/g. Thus, the comparison validated the effectiveness of the sensitivity-improving method within the same geometric dimension. Furthermore, by optimizing both the cross-section shape and the geometrical ratios of the elastic extension to the piezoelectric layer simultaneously, the overall sensitivity can be increased by 8.15 times greater than that of the rectangular section cantilever sensor, which has great potential applications in high-resolution mass sensors.
