  Electronic sensors play important roles in various applications, such as
industry and environmental monitoring, biomedical sample ingredient analysis,
wireless networks and so on. However, the sensitivity and robustness of current
schemes are often limited by the low quality-factors of resonators and
fabrication disorders. Hence, exploring new mechanisms of the electronic sensor
with a high-level sensitivity and a strong robustness is of great significance.
Here, we propose a new way to design electronic sensors with superior
performances based on exotic properties of non-Hermitian topological physics.
Owing to the extreme boundary-sensitivity of non-Hermitian topological zero
modes, the frequency shift induced by boundary perturbations can show an
exponential growth trend with respect to the size of non-Hermitian
topolectrical circuit sensors. Moreover, such an exponential growth sensitivity
is also robust against disorders of circuit elements. Using designed
non-Hermitian topolectrical circuit sensors, we further experimentally verify
the ultra-sensitive identification of the distance, rotation angle, and liquid
level with the designed capacitive devices. Our proposed non-Hermitian
topolectrical circuit sensors can possess a wide range of applications in
ultra-sensitive environmental monitoring and show an exciting prospect for
nextgeneration sensing technologies.
