The limits of resonant tunneling diode subharmonic mixer performance

A theoretical analysis of the performance of subharmonically pumped mixers using resonant tunneling diodes is given based on the I-V curve of the latter. It is found that, in addition to the usual symmetry requirement, there are optimum positive and negative differential resistance values, as well as optimum current peak-to-valley ratios in this application. It is shown that, by carefully designing the diode, mixers can be built that will show positive conversion gain while operating in a harmonic mode.