High power durable electrodes for GHz band SAW duplexers

We have been successful in developing a high power durable electrode for GHz band SAW filter. We previously reported that we developed a 4-layered AlScCu/Ti/AlScCu/Ti electrode of high power durability which, in the 800 MHz band, made it possible for SAW filters to be applied to antenna duplexers. This electrode is suitable for mass-production, too. But, the power durability of this electrode was insufficient for the 1.9 GHz band SAW duplexers. It is certain that the reason for this electrode having a shorter lifetime than that of 800 MHz band SAW filters is the SAW stress that increases proportionally to the frequency. Therefore, we examined the potential of AlMgCu/Ti/AlMgCu/Ti and AlZrCu/Ti/AlZrCu/Ti. Moreover, we optimized the structure of 4-layered electrode. In power durability evaluations, each electrode lifetime was estimated to be more than 50,000 hours at an ambient temperature of 50°C an input power of 29 dBm. This result indicates sufficient power durability for GHz band SAW duplexers