COM analysis for LSAW filters

This paper presents a modified COM - based analysis for LSAW ladder and coupled resonator filters. The acoustic sources between the adjacent elements (transducers and gratings) are taken into account by using a gap-type cell instead of a traditional electrode-type cell. Mutual capacitances between the elements are calculated from an electrostatic analysis. The Y-matrix of the device is obtained by a combination of P-matrix cascading and the circuit analysis. The presented analysis is applied to the devices with chirped and apodized elements. A good agreement between calculated and experimental results is demonstrated.