Grating-mode-type wide-band SAW resonators for VCOs

Grating-mode-type surface acoustic waves (SAWs) that are particularly suitable for wide-band SAW resonators were found. Their bandwidths are larger than 13%. Their spurious responses originating from Rayleigh waves are almost negligible when the Al-grating thickness is optimized for the cut angle of substrate. For example, the ratio of the Al-grating thickness to the SAW wavelength must be required within 0.125±0.007 for 15°-rotated Y-cut X-propagating lithium niobate. These SAW resonators were applied to UHF-band voltage-controlled oscillators. They achieved a high control-voltage sensitivity of 13.5 MHz/V (3.2%/V) and a high phase-noise performance of <-115 dBc/Hz offset 25 kHz from the carrier