Guidelines for the design of high-efficiency mode avalanche diode oscillators

In this paper, we have developed a set of guidelines for the design of high-efficiency mode avalanche diode oscillators, based on the previously published theory of this mode. An important feature in the development is the "design triangle"--an area in design space which is compatible with the existence of a set of waveforms characterized by efficiencies of up to 60 percent. The particular subregion of the design triangle which is most suitable depends on whether the goal is CW or high-pulsed-power operation. Examination of available data for the highest efficiency oscillators indicates that most of these are likely exhibiting oscillations of the type described and that the quantitative results developed are indeed applicable. In order to achieve extremely high efficiencies, severe circuit demands must be met; doing this systematically is likely to prove quite difficult. Combining the design results with thermal calculations indicates that one may anticipate UHF or L-band single-chip CW power levels of over 20 W with a conventional copper heat sink and considerably more power with a heat sink of type IIA diamond.