ABSTRACT
Many frequencies may interact in a varactor, and of those, some may be useful inputs or outputs, while the others are idlers that, although they are necessary for the operation of the device, are not part of any input or output. For instance, to generate high harmonics in a frequency multiplier it is more or less necessary to allow current at intermediate harmonics (idlers) to flow. Such idler circuits are usually realized as short-circuit resonators, which maximizes the current at idler frequencies.
