P2N-3 Single Port SAW Resonators Design for Arbitrary Reflection Phase

This work deals with some aspects of resonator performance improvement on unidirectional substrates with arbitrary reflection angle. A design concept is proposed based on the use of resonators with slight (by about 1-2%, depending on the material properties) frequency increase (or decrease, for opposite phase) of the IDT pitch in the transducer center for bi-directional substrates. For naturally unidirectional orientations properly placed linear chirp transducers with pitch variation of the same order of magnitude are found to give practically useful results, while for arbitrary phase angles in between of these two extreme cases the position of the transducer pitch maximum (minimum for opposite phase) is shifted from the center to the corresponding side of the transducer in accordance with the phase. Relevant the results are compared with experimental data on langasite substrates