March 2014
Intermediate to advanced
624 pages
26h 33m
English
In this section, we describe a type of microwave negative-conductance device that operates by a combination of carrier injection and transit-time effects. Diodes with simple p-n junction structure, or with variations on that structure, are biased to achieve tunneling or avalanche breakdown, with an a-c voltage superimposed on the d-c bias. The carriers generated by the injection process are swept through a drift region to the terminals of the device. We shall see that the a-c component of the resulting current can be approximately 180° out of phase with the applied voltage under proper conditions of bias and device configuration, giving rise to negative conductance and oscillation in a resonant circuit. Transit-time devices ...