10E-3 GPS SAW Filter Using A Wafer Level Technique

A wafer-level assembled SAW filter on 36Y-X LiTaO₃ with a size of 1.6x0.8 mm is presented. The SAW filter has six solder balls with a size of 0.25 mm diameters. The reason of the use of the 0.25 mm balls is that it is easy to mount the devices onto a printed circuit board using a conventional placement machine. The SAW filter is designed for a GPS RF stage application and has a center frequency of 1.5 GHz. The frequency characteristics of the SAW filter are almost the same as the ceramic packaged SAW filter. An insertion loss of 1.1 dB was obtained. Furthermore, a smaller SAW filter with 1.0x0.8 mm in size is demonstrated.