Transferred electron (Gunn) amplifiers and oscillators for microwave applications

Transferred electron amplifiers and oscillators are now well established as important members of the family of active microwave solid-state devices. The combination of power output, gain-bandwidth product, and noise figure that has been achieved with stable linear transferred electron amplifiers cannot be matched by any other type of microwave solid-state amplifier. Transferred electron oscillators have produced the highest power output obtained so far from a single solid-state device at microwave frequencies, they can be electronically and mechanically tuned over larger frequency ranges than other types of solid-state oscillators, and well designed transferred electron oscillators have exceptionally low AM and FM noise. An introductory survey of the history and the current status of the theory, technology, and application of transferred electron devices is presented. The future outlook for these devices appears bright.