3.2.4 Programmable reference parameters for resonance locking in electro-thermal piezoresistive cantilever sensor

Setiono, Andi; Fahrbach, Michael; Xu, Jiushuai; Nyang’au, Wilson Ombati; Bertke, Maik; Wasisto, Hutomo Suryo; Peiner, Erwin

doi:10.5162/sensoren2019/3.2.4

Cited by 1 publication

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“…This condition presents an unavoidable parasitic element, resulting in a non-ideal spectral of the amplitude and phase response (delineated in Figure 1b), called an asymmetric spectral shape (black line) and a reversing phase (red line), respectively. The asymmetric spectra are always accompanied by the reversing phase response, which has ambiguous characteristics and is detrimental to real-time operation with a phase-locked loop [23,24]. Therefore, optimizing both the amplitude and the phase spectra is essential.…”

Section: Resonant Frequency Transfer Function Analysismentioning

confidence: 99%

Replicating Spectral Baseline for Unambiguous Frequency Locking in Resonant Sensors

Setiono,

Nelfyenny,

Nyang’au

et al. 2024

Sensors

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Electrothermal piezoresistive resonant cantilever sensors have been fabricated with embedded actuating (heating resistor) and sensing (piezo resistors) parts, with the latter configured in a Wheatstone bridge circuit. Due to the close spacing between these two elements, a direct thermal parasitic effect on the resonant sensor during the actuating-sensing process leads to asymmetric amplitude and reversing phase spectral responses. Such a condition affects the precise determination of the cantilever’s resonant frequency, f0. Moreover, in the context of phase-locked loop-based (PLL) resonance tracking, a reversing phase spectral response hinders the resonance locking due to its ambiguity. In this work, a replica of the baseline spectral was applied to remove the thermal parasitic effect on the resonance spectra of the cantilever sensor, and its capability was simulated through mathematical analysis. This replica spectral was subtracted from the parasitized spectral using a particular calculation, resulting in optimized spectral responses. An assessment using cigarette smoke particles performed a desired spectral shifting into symmetrical amplitude shapes and monotonic phase transitions, subsequently allowing for real-time PLL-based frequency tracking.

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Section: Resonant Frequency Transfer Function Analysismentioning

confidence: 99%