The authors have introduced the operation principle and methods for improving the characteristics of SAW and BAW devices in this chapter. Among the various MEMS resonators, SAW and BAW devices have been among the most successfully commercialised fields, particularly for wireless RF applications. The communication architecture was described, which is the common ground in device development. Also, the improvement of the characteristics has been described in terms of the requirements of such applications. With regard to techniques for improving performance, a very wide range of knowledge of engineering from materials to numerical dispersive analysis is required. The authorshave only given an outline of these fields. Details can be found in the books and papers cited in this chapter.

Chapter Contents:

• 8.1 Introduction
• 8.2 Basis of the RF front-end circuit
• 8.2.1 Multiple access systems
• 8.2.1.1 Duplexing: uplinks and downlinks
• 8.2.1.2 Multiple access
• 8.2.2 Communication architecture
• 8.2.2.1 Basic concept
• 8.2.2.2 Receiver architecture
• 8.2.3 Remarks
• 8.3 Resonators and filters
• 8.3.1 Classification of resonators
• 8.3.1.1 SAW resonators
• 8.3.1.2 BAW resonators
• 8.3.2 Filter design
• 8.3.2.1 Characterisation of resonators
• 8.4 Performance improvement
• 8.4.1 Improvement of coupling coefficient
• 8.4.1.1 Improvement of k with electrode material
• 8.4.1.2 Enhancement of piezoelectricity
• 8.4.2 Improvement of Q
• 8.4.3 Low-Tcf technologies
• 8.4.4 Suppression of spurious responses
• 8.4.4.1 Dispersion in a piezoelectric plate
• 8.4.4.2 Energy-trapping mode
• 8.4.4.3 Spurious responses and piston modes
• 8.4.4.4 Design of dispersion diagram
• 8.4.4.5 Feedback from BAWs to SAWs
• 8.5 Summary
• References

Inspec keywords: bulk acoustic wave devices; micromechanical resonators; surface acoustic wave filters; resonator filters; oscillators

Other keywords: communication architecture; numerical dispersive analysis; BAW resonators; MEMS resonator filters; SAW resonator; wireless RF applications

Subjects: Oscillators; Acoustic wave devices; MEMS and NEMS device technology; Passive filters and other passive networks