Wireless sensors based on micromachined tunable resonators are important in a variety of applications, ranging from medical diagnosis to industrial and environmental monitoring. The sensitivity of these devices is, however, often limited by their low quality (Q) factor. Here, we introduce the concept of isospectral party–time–reciprocal scaling (PTX) symmetry and show that it can be used to build a new family of radiofrequency wireless microsensors exhibiting ultrasensitive responses and ultrahigh resolution, which are well beyond the limitations of conventional passive sensors. We show theoretically, and demonstrate experimentally using microelectromechanical-based wireless pressure sensors, that PTX-symmetric electronic systems share the same eigenfrequencies as their parity–time (PT)-symmetric counterparts, but crucially have different circuit profiles and eigenmodes. This simplifies the electronic circuit design and enables further enhancements to the extrinsic Q-factor of the sensors.
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This work has been supported by the NSF ECCS grant no. 1711409 (to P.-Y.C.), the Air Force Office of Scientific Research, the Welch Foundation with grant no. F-1802 (to A.A.) and the Army Research Office (ARO) grant no. W911NF-17-1-0481 (to R.E.-G.). Device fabrication was carried out in the Nano Fabrication Service Core (nFab) at the Wayne State University.
The authors declare no competing interests.
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Chen, P., Sakhdari, M., Hajizadegan, M. et al. Generalized parity–time symmetry condition for enhanced sensor telemetry. Nat Electron 1, 297–304 (2018). https://doi.org/10.1038/s41928-018-0072-6
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