Design and applications of two-port SAW resonators on YZ-lithium niobate

The fundamental design criteria for two-port SAW resonators are discussed. The distributed reflective arrays are modeled as lossy repetitively mismatched transmission lines with impedance mismatch ε and expressions for the reflection magnitude and phase are given. An experimental technique is described to directly determine both ε and the proper placement of the input/output transducers. Experimental two-port resonator filters have been realized having Q's of 2000-5000, 5-7 dB insertion loss, and ∼35-dB sidelobe suppression. By electrically cascading three resonators, sidelobe suppression of ∼80 dB has been achieved. Resonator structures have been developed in which continuous frequency tuning up to 0.18 percent has been obtained by electronic means.