A linear resonator consists of IDT located between reflectors on the piezoelectric board. A standing wave is made, when two reflectors are away as far as an integer rate of half-wavelength of the traveling wave in terms of authorized continuous reflection. This wave has amplitude, and the resonant has applied it.

Design types include IIDT (Interdigitated Interdigital Transducers), Ladder type, and DMS (Double Mode SAW) type. This filter is used for antenna duplexer for mobile/wireless devices, RF filter used for front-end stage, one/two-way pager, keyless system, fixed frequency, and tunable oscillator circuit.

The two-way IDT linear element consists of input stage IDT, propagation path, and output stage IDT. When a signal is authorized to input electrode located on the piezoelectric board, an electric signal is converted into a surface acoustic wave signal between IDTs, due to piezoelectric effect, and is conveyed along with propagation path. This device, in turn, detects it as the electric signal through the output stage IDT.

Used for IF (Intermediate Frequency) filters for mobile/wireless receivers, and pages IF filters for TVs, Delay lines, sensors, repeaters for optical communications, Nyquist filters for microwave digital radios, and VCO circuits.

With a method to configure reflectors within IDT and progress surface acoustic wave to only direction by incidence signal, the insertion loss and ripple of bandpass can be reduced, and group delay can improve. However, against these advantages, the bandpass becomes narrow and an attenuation feature becomes bad. Design types include SPUDT, R-SPUDT, Z-Path, and Slanted type. This filter is used for mobile/wireless transceiver, low loss IF/RF filter, low loss Delay line, and radar system.