The surface acoustic resonator could be referred to as SAWF or SAW, which is a kind of transducer type passive band-pass filter. With the piezoelectric effect applied in acoustic wave propagation properties of piezoelectric ceramic, lithium niobate, or quartz crystal isobaric, it is widely used in TV-set, VCR as a frequency selective element. Its most used frequency is 433.92MHz and 315MHz, but it could be customized with clients' demands.