A SAW device (11) includes a SAW element (13) which is bonded onto a support substrate (12) in a face down mode through solder (19, 20), and a metal cap (21) enclosing the SAW element (13). Assuming that and .alpha..sub.1, .alpha..sub.2 and .alpha..sub.3 represent the thermal expansion...http://www.google.co.uk/patents/US5712523?utm_source=gb-gplus-sharePatent US5712523 - Surface acoustic wave device
