Magnetostatic waves take over where SAWs leave off

Acoustic waves of Surface Acoustic Wave (SAW) devices travel in quartz approximately 3,000 m/sec, while magnetostatic waves (MSW) have velocities of 500,000 m/sec. From these numbers it can be seen that, while time delays of microseconds are attainable with SAWS, magnetostatic waves are best applied where nanosecond time delays are required. An overview is presented of the mechanisms involved in exciting, guiding, and detecting magnetostatic waves, and the possible device applications. Methods are discussed for linearizing the dispersion curves, taking into account also compensation methods for the dispersion of MSW over the operating ranges of oscillators, filters, and time delay devices. Important developments which made magnetostatic wave device application a reality are related to the growth of uniform large pure high quality epitaxial YIG films, and an advance related to the design and fabrication techniques of efficient RF to MSW transducers.