Abstract
A new device, the quantum-barrier-varactor diode (QBV diode), is proposed for use in multipliers for millimetre waves. Since the capacitance/voltage characteristic is symmetric, only odd harmonics are obtained. Hence there is no idler circuit to consider for the tripler and only one for the quintupler. It is shown that for triplers and quintuplers, the theoretical efficiency using QBVs is comparable or possibly larger than using Schottky varactor diodes.