Impedance Matching Of SAW Filters

SAW filters come in a variety of realizations and these employ different physical principles as a basis for their design. Resonant devices make use of the usual resonant condition of a resonator or group of coupled resonators to select a passband and reflect reject bands from an input signal. Transversal devices employ either directional or bi-directional transducers to sample the phase and amplitude of the input waveform, and, by weighting, manipulate the impulse response of the input to provide filtering. Each device class of SAW filter or type of filter within a class has particular transmission performance characteristics, thermal behaviour, packaging constraints and associated cost trade-offs.