Thin film bulk acoustic wave devices for applications at 5.2 GHz

Infineon Technologies has started volume manufacturing of bulk acoustic wave (BAW) filters for GSM mobile handset applications in mid 2002. In this paper the feasibility of BAW band filters around 5.2 GHz is discussed. The manufacturing is reviewed and the measurement results are discussed. Latest results from manufactured BAW resonators are shown a sufficient performance in order to fulfill the Wireless-LAN communication requirements. The manufactured single resonators show quality factors Q of up to 900 and a piezoelectric coupling factor k/sub eff//sup 2/ of 6.5%.