Bulk acoustic wave coupled resonator filters synthesis methodology

Frequency Design of Lossless Passive Electronic Filters: A State-Space Formulation of the Direct Synthesis Approach

“…where x Ω , y Ω and z Ω depend on the frequency interval Ω and are provided by (13), and Proof. Cf Appendix C.…”

“…This approach usually leads to time-efficient methods, as the standard Butterworth and Chebyshev methods, but is limited to particular circuits such as LC-ladder filters [10]. It has been regularly updated in the last decade in order to synthesize more general filters, such as LC-resonator ladder filters [9], [11], [12] or Acoustic-Wave (AW) ladder filters [7], [9], [13], [14]. However, this approach does not enable to consider technological constraints and generally leads to introduce additional undesirable elements (see [14] for instance).…”

Estimation of Material Damping Coefficients of AlN for Film Bulk Acoustic Wave Resonator

“…This equation also fits the experimental data fairly well, if all the quantities of the material are known with adequate precision. The Gruneisen numbers for the longitudinal wave is 1.2 and 0.6 for shear wave as presented in [20].The attenuation of AlN given in [19]is 0.08 dB/cm at 1 GHz. The value of the stiffness proportional damping coefficient (β) is estimated by using the 1-D viscoelastic wave equation as explained in [21]given as…”

Synthesis of acoustic wave filters : ladder and transversal topologies : towards a practical implementation

“…Oddly enough the paths of filter synthesis and acoustic wave filters had not cross until recent years. Actually, the first works related to the topic didn't use closed-form expression synthesis techniques but optimization methods of lumped element models based on preliminary given data related to the acoustic technology [34], [35] and [36]. The coupling matrix used to synthesize acoustic filters appears in [37], however the related results are only valid for Coupled Resonators Filters (CRF), which have a very particular working principle and are still a residual percentage of all the EA filters in the market.…”