2. Similarities and differences between electroacoustic filters

Fundamental difference from electromagnetic filters

What all electroacoustic filters have in common is that they convert electrical energy into acoustic energy and vice versa. The advantage of this transition to the acoustic domain is that acoustic waves propagate at a much lower speed than electromagnetic waves. Depending on the material and crystal cross-section, the acoustic speed is between 2,000 and 10,000 m/s, as opposed to 300,000 km/s for electromagnetic waves. As the dimensions of a component are proportional to its wavelength, it follows that at a given frequency an acoustic filter will be much smaller than an electromagnetic filter. Above a few gigahertz, however, this becomes a disadvantage.

Transduction, piezoelectric effect

The transformation...