Bandpass Phase Correction Methodology for Ladder-Type Acoustic Filters

Phase matching of ladder-type filters based on micro-acoustic technology is an important part of duplexer and multiplexer design. However, it cannot be straightforwardly applied in direct bandpass synthesis methodologies because of essential differences between lowpass and bandpass approaches. A novel filtering function able to accommodate a new phase control term is proposed in this paper. Taking into account the phase correction from the beginning of the synthesis provides additional advantages in the network design.