AbstractSimulations using a combination of the finite‐element method and the analytical method as well as experiments are used to study new‐mode‐type SAWs. First, in 171°YZé‐LiNbO3, it is found that there exists a longitudinal leaky SAW with a high acoustic velocity and a high Q in a grating structure with an Al film thickness of 0.084 wavelength. The acoustic velocity is 6100 to 6500 m/s and the Q values are more than 4000 (computed) at both the resonance and antiresonance points. These excellent properties are suitable for high‐frequency SAW devices. Next, in 15°YX‐LiNbO3, it is found that there exists a grating mode SAW of a transverse wave type in a grating structure with an Al film thickness of 0.125 wavelength. In this case, k2 has an extremely large value of 28.5% and hence the mode is suitable for a SAW resonator for use in a voltage‐controlled oscillator. By means of this SAW, SAW‐VCOs at 400 and 170 MHz for mobile communication are fabricated. At 400 MHz, the frequency variable width is 54 MHz (3.2%/V) and the phase noise is less than –115 dBc/Hz at 25 kHz; the corresponding values at 170 MHz are 24 MHz (3.4%/V) and < –12 dBc/Hz at 25 kHz. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(4): 49–58, 2001