| The active element of the superlattice oscillator is a doped superlattice subject to a static voltage. The superlattice has a negative differential resistance as a consequence of Bloch oscillations of electrons. The negative resistance gives rise to propagating dipole domains and to the generation of microwaves. I will discuss the origin of the negative resistance and present experimental results for GaAs/AlAs superlattice oscillators. Depending on the size of the resonator that contains an active superlattice, an oscillator generates microwave radiation at frequencies in the range from 1 GHz to about 150 GHz. The efficiency (several percent) for the conversion of electric power to microwave radiation power is comparable to the efficiency of other types of microwave oscillators. At present, compact microwave wave oscillators, operating at room temperature, are available at frequencies up to about 150 GHz. In principle, superlattices should be suitable as active elements of microwave oscillators for frequencies well above the present limit. |
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