"Semiconductor voltage controllable reactance"

A germanium alloy-junction diode has been developed which is useful as a voltage controlled reactance up to and including ultra high frequencies. Special attention has been paid to electrical losses and lead inductance. Typical performance at 500 mc and 6 volts bias is a capacitance of 30 μμfd with a change in capacitance at this voltage of 2 μμfd/volt, a lead inductance of 6 mill microhenries, and a Q of 40. Theoretical expressions are developed for the various parameters involved, and these results agree well with measured result,s. Diodes to meet special operating requirements can therefore be designed. The variable reactance diode has many applications such as for mixing, frequency modulation, automatic frequency control, frequency selective circuits, and dielectric amplifiers.