Analysis and optimal SAW ladder filter design including bonding wire and package impedance

This paper describes analysis and optimal design of SAW ladder filter, which includes effect of bonding wire and package impedance. Attenuation performance of SAW filter is influenced by not only their design conditions but also bonding wire effect and package design structure. To confirm their effect, theoretical and experimental analysis were studied, and it was found that electrical resonance generated by SAW element capacitance including capacitance of electrode fingers and stray capacitance, bonding wire and package inductance influence an attenuation characteristics. By using their characteristics effectively, we propose new improvement method of stop-band rejection.