Recent research aims to enhance piezoelectric energy harvesting for low-power electronic circuits like sensors and wireless systems using cantilever energy harvesters with piezoelectric substrates featuring auxetic structures such as reentrant, missing rib, and double arrowhead patterns. Employing the Wentzel–Kramers–Brillouin (WKB) method is a novel method to analyze these structures based on Euler–Bernoulli beam theory. The study comprises theoretical analysis, finite element simulations, and experimental tests. The highest power output is achieved when consecutive masses excite the bridge using the double arrowhead auxetic unit cell substrate, yielding power outputs of 1.152 μ W / N . The effect of increasing unit cells has also been investigated. Highlights Creating unique analytical methods for auxetic substrate use in energy harvesters. Analyzing three auxetic harvester substrates, emphasizing their unique performance. Auxetic harvesters were studied under various bridge simulator base excitations. The study examines three auxetic structures' effect on harvested power. Study of moving masses' influence on bridge simulator, weights, and velocities.