Citation:
Meiling Zhu, Paul B. Kirby, Design study of piezoelectric micro-machined mechanically coupled cantilever filters using a combined finite element and microwave circuit analysis, Sensors and Actuators A: Physical, Volume 126, Issue 2, 14 February 2006, Pages 417-424.
Abstract:
A new mechanical filter structure is presented which comprises two silicon
cantilevers mechanically coupled by a silicon linkage with thin film
piezoelectric transducers providing electrical input and output signals. The
resonance behaviour of such a structure results in a band-pass filter response,
having a band-width determined by the frequency separation between the closely
spaced in-phase and out-of-phase vibrational modes of the two coupled
cantilevers. A detailed configuration design analysis, filter simulation and
optimisation of performance is undertaken using a new modelling approach
combining microwave circuit theory and finite element analysis to evaluate the
generalised (A, B, C and D) and scattering (S) circuit parameters of the filter.
Two significant features of the filters have emerged from the derived analyses
and simulations: (1) with correct design filter Q-values can reach several
thousand which is much higher than the Q-values (80) of uncoupled cantilevers,
(2) the Q-value is determined by the configuration of the silicon linkage and so
is under the designer's control. The position and length of the linkage that
give optimum Q and minimum insertion loss are determined.
