Synthesis of Chebyshev/Elliptic Filters Using Minimum Acoustic Wave Resonators

Acoustic wave (AW) filters for next-generation wireless communication systems are designed to prevent signal interference and to be as small as possible. Using a pole-zero extraction method with a ladder-type AW filter, this paper proposes an algorithm to optimize the parameters for each AW resonator. The pole-zero positions of the equivalent circuit model are aligned with those of a Chebyshev or elliptic filter in the s-domain in order to give a frequency response that satisfies the system requirements in terms of insertion loss, out-band attenuation, and selectivity. The optimized parameters produce a system that has the minimum number of resonators to fulfill the filter performance specifications, with reduced manufacturing cost, which occupies a smaller area. Finally, the system is validated using a simulation with a LTE Band3 Rx elliptic filter and the parameters for an equivalent modified Butterworth-Van Dyke model (mBVD) for each resonator.