Abstract: A phase shifter uses a PIN diode or diode pairs operated in a switching mode to switch transmission-line elements for phase-shifting radio frequency or microwave signals. A drive circuit for each diode(s) includes a FET switch controlled by a first level of a bilevel control signal to apply B+ to forward bias the diode(s) with a forward current. When forward biased, the active region of the diode(s) becomes flooded with charge carriers. The first FET switch is turned OFF by a second level of the bilevel control signal, and a second FET switch is turned ON to apply a reverse bias voltage to the diode(s) to render them nonconductive. Before the diode(s) become nonconductive, the excess charge carriers must be swept out of the diode(s). To achieve fast switching, the second FET switch must draw a large current for a short time as the excess charge carriers are removed.

Abstract: A flux drive gyromagnetic system such as a gyromagnetic waveguide phase shifter is temperature compensated by measuring the flux change in the gyromagnetic material during a reverse in saturation magnetization, comparing that change to the change under reference conditions and modifying the drive used to set the gyromagnetic material to a non-saturated condition in accordance with the results of the comparison.

Abstract: A resistor inserted between the collector of a common emitter transistor in a cascode amplifier and the emitter of the ensuing common base-amplifier transistor in conjunction with an operational amplifier responds to the collector current of the common emitter transistor to develop a degenerative-feedback-voltage signal for application to its emitter-base circuit.