Dc flow considerations for crossed-field acoustic amplifiers and other solid-state traveling-wave devices

The direct Current flow in two simple device structures used for crossed-field, traveling-wave devices is analyzed, and some properties of the flow which can affect the RF performance are studied in detail. The results show nonuniform flow to be significant only in localized regions, which can be made small by a proper choice of electrode and sample geometry. Approximate formulas are derived for estimating the important flow parameters of interest in specific applications. As an example, the effect of nonuniform flow on the acoustic amplifier is estimated. The deflection and refraction of a shear-wave acoustic beam in InSb at 77°K is found to be negligible, but the gain is reduced appreciably for large µB0. Considerations entering into device design, such as heat sinking and the provision of an RF circuit, are also discussed with regard to an optimum choice of electrode configuration for a rectangular device.