SAW resonator design and fabrication for 2.0, 2.6 and 3.3 GHz

Direct-write electron-beam lithography has been used to fabricate surface-acoustic-wave (SAW) resonators in quartz at 2.05, 2.60, and 3.30 GHz. Typical 2.05-GHz devices show unloaded Q factors of about 2700 and insertion losses of about 9 dB. The best 2.60-GHz devices have unloaded Q of about 2000 with insertion losses less than 11 dB. Preliminary 3.3-GHz devices have shown unloaded Q of about 1600 and insertion losses of 17 dB. These results are for devices tested in chip form in a 50-Omega system. The fabrication of a fundamental-mode resonator with center frequency exceeding 2.6 GHz is claimed to be unmatched in the literature. These results are due in part to improvements in design and electron-beam direct-write capabilities. Design and fabrication of SAW resonators above 2 GHz are described, test results for several wafers including preliminary phase noise measurements for devices at 2 GHz are reported, and problems associated with testing these devices are discussed.