Influence of minority-carrier storage on performance of semiconductor-diode modulator

The nature of minority-carrier storage effects in an ideal plane p-n junction are considered with particular reference to the shape of the reverse-current pulse that appears when the device is switched from forward to reverse bias. By approximating to this, a modulating function is formulated for a resistively terminated single-diode shunt modulator switched by a squarewave carrier, and the variations of insertion and conversion losses with frequency are calculated for a typical circuit. The performance of the modulator may be improved by three techniques whose values are assessed with particular reference to loss stability with changes in the diode parameters. The applicability of the theory to practical diode types is considered and the problem of sinewave switching outlined.