Design of MEMS mass sensors based of flexural phononic crystals

Abstract

In this work, a piezoelectrically actuated MEMS flexural phononic crystal (PC) mass sensor aimed at biosensing applications, and based on a single crystal silicon beam with periodic perforations, is presented. We introduce a transmission matrix approach based on the Timoshenko beam theory suited for the fast design of such devices. The calculated transmission spectra are in excellent agreement with FEM simulations. A preliminary estimate of the device sensitivity, assuming the prostate specific antigen (PSA) as the target analyte, is reported

A critical review of reduced one-dimensional beam models of piezoelectric composite beams

“…The symmetric triple layer bimorph shown in Figure 1 is typically polarized for flexural deformations. For unimorph beams, longitudinal and flexural deformations are intrinsically coupled (Luschi and Pieri, 2015). The expressions of the coefficients appearing in equation (20) are summarized in Appendix 2, where the expressions for unimorph beams are reported as well.…”

“…Moreover, if, for example, the electric port is closed on a resistive load R (a configuration typically used to evaluate the performances of piezoelectric energy harvesters (Erturk and Inman, 2009; Karami et al, 2011; Rafique and Bonello, 2010; Reissman et al, 2016)), the additional equation is required. The method of the transmission matrices can be used as an efficient solution technique for this system of differential equations (21) to (24) (Luschi et al, 2016; Luschi and Pieri, 2015; Reissman et al, 2016)…”

A Simple Method for the Design of 1-D MEMS Flexural Phononic Crystals

“…The actual number of holes along 𝑦 in the holed segment does not influence the PnC behavior, as long as it is large enough that the equivalent material hypothesis holds. Having a large number of holes along 𝑦 increases the surface to volume ratio, a property linked to an increase in sensitivity in resonant mass sensors [10,[21][22][23].…”

“…PnCbased anchors were shown to reduce mechanical losses in standard MEMS resonators [8]. Other applications include mass sensors [9,10], acoustic waveguides [11] and thermal insulators [12].…”

“…In this paper, we present a method for the design of 1D flexural MEMS PnCs, where the periodicity is typically obtained by introducing a regular pattern of holes in the structural layer [4,6,[8][9][10]12]. This choice reduces the degrees of freedom of the design and substantially simplifies the The authors are with the Dipartimento di Ingegneria dell'Informazione, Università di Pisa, Pisa, 56122 Italy (e-mail: luca.luschi@for.unipi.it, {f.pieri, g.iannaccone}@iet.unipi.it).…”