Patent technology portfolio for SAW filters

Patent portfolio or patent mapping is a basic technology to pursuit research and development. The technology in patents goes 2 to 5 years ahead beyond the current devices and manufacturing technology. We had investigated the patents for the SAW (surface acoustic wave) filter through WPI (world patent index) and PATOLIS (patent on-line information system) database since 1971 through 1994. In this paper, we have found 690 US patents and 3,673 Japan patents. Zenith of USA has 14% of patents of 10 main companies, it is interesting to compare with 21% of USA navy and army secretaries and 13% of Clarion of Japan in USA issued patents. The history and trend of the SAW filter technology and the analysis of SAW filter manufacturing (actually patenting) companies are discussed include the ultrahigh frequency (UHF) SAW filters for mobile communication