Kyocera Corp. developed the SF08 series, a line of SAW filters measuring only 0.8 mm x 0.6 mm x 0.38 mm, which is intended for use in mobile devices.
The filter is expected to be used in GSM and UMTS mobile phones.
The product was obtained by mounting and sealing the SAW device on a substrate and then coating it with resin. As a result, the company succeeded in achieving a filter with a size of only 0.8mm × 0.6mm and a profile of only 0.38 mm.
The filter has a structure in which the mounted SAW device and its periphery are airtightly sealed. Thus, the filter has a high resistance against mechanical impacts such as vibration and drop, and an excellent durability in the transfer molding process required to mount the filter on a module.
The maximum insertion loss is 2.5 dB (standard loss: 1.6 dB). The minimum attenuation on the 824-849 MHz frequency band is 45 dB (standard attenuation: 56 dB). The reduction of line length contributed to improve these characteristics, the company said.
Kyocera employed chip size package (CSP) technology. The company will begin volume production with the monthly output of 5 million units from January 2008. It also plans to expand the production scale to yield 25 million units per month from January 2009 and increase the output.
According to Kyocera, filters supporting CDMA, J-CDM and GPS will be added to the SF08 series in addition to the GSM- and UMTS-compatible products.