Multimode bandpass SAW filter using reconfigurable resonance technology

The trend to include more frequency bands in mobile phones has so far been addressed by adding more fixed frequency Surface Acoustic Wave (SAW) filters and switching the RF path to accommodate each band. As more bands are needed, a reconfigurable SAW filter is of great interest if performance is not compromised. Here we present the results of a new approach to designing multiband filters. The SAW resonators remain common to all the modes of the device, and non-resonant elements, (inductors and capacitors) are adjusted to reconfigure the passbands. A two-mode proof of concept is presented that uses the same fixed SAW resonators and demonstrates a six percent (6%) change in passband frequencies.