High-power step recovery diodes and saturable inductors in radar pulse modulators

Step recovery diodes are characterized by two distinct reverse recovery phases. During the first phase the minority charge is removed at a low reverse voltage, while during the second phase the reverse voltage builds up rapidly, giving rise to the name step recovery. If such a diode is operated cyclically, the minority charge injected by the forward current is preserved and the minority charge is recovered during the first phase of the reverse recovery interval. This situation is the dual of a nonlinear inductor with rectangular hysteresis loop core material operated cyclically in and out of saturation. Thus, we can use the step recovery diode to construct a pulse compression network which essentially is the dual of the nonlinear magnetic pulse compression network. The nonlinear dielectric pulse compression network which uses step recovery diodes can efficiently generate high-power pulses down to pulse widths of a few nanoseconds. In addition the dielectric network provides much higher pulse compression per stage, thus reducing the volume, weight, and number of components.