Impedance element SAW filters

Over the last few years a new generation of surface acoustic wave (SAW) devices with low loss and operating at high frequency have been invented to meet the demand of mobile communication systems. Besides outstanding electrical characteristics, these filters need to have small size and weight, must be highly reproducible, need no tuning, must be very cheap and if necessary, able to handle power levels up to a few Watts. In this work we introduce a new class of SAW filters-balanced bridge impedance element filters-which have all these advantages: low insertion loss, extremely small size and weight, a wide variety of centre frequencies and passbands, excellent suppression in the stopband and require no external matching circuits