Design of super high power SAW filter

It is well known that the surface acoustic wave (SAW) filter is not well adapted to high power use. To improve its power characteristic, the use of a number of identical SAW filters to compose a parallel connection SAW filter system which has the same transmission characteristics as a single one but is durable enough for high power use is proposed. To realize this end, a matching method using the conjugate image impedances is needed to design the matching circuits of the system. In experimenting, the authors used the 800-MHz-band SAW filter to compose a two-piece, a three-piece, and a four-piece SAW filter system which can endure, respectively, 4.0 W, 6.0 W, and 8.0 W input power for more than 30 min without damage. This result also gives the possibility of designing super-high-power SAW filters using the technique described above