Bulk Acoustic Wave Devices - Why, How, and Where They are Going

Bulk Acoustic Wave (BAW) devices have been researched for several decades with great promise and are now rapidly growing in the marketplace, migrating from the military and high-end industrial markets into consumer wireless applications. Although BAW devices can be fabricated for use below 500 MHZ, the economic sweet spot for BAW is above 1.5 GHz. At 1.8-1.9 GHz, BAW ladder filters become very competitive against Surface Acoustic Wave (SAW) devices with improved performance and against ceramic filters with significant size reduction in handset designs. The highest penetration for BAW devices has been in the area of PCS and UMTS duplexers. The cost of BAW devices has been reduced to the point of being very competitive with existing filter and duplexer technologies. The future of BAW devices will show migration to higher frequencies and potential integration with active integrated circuits. OVERVIEW