Abstract: A limiting filter has nonlinear signal limiting devices integrally connected to the filter structure so that as the power level of input signals increase the nonlinear signal limiting devices decrease their impedance in response thereto, detuning the filter. Filter isolation thus becomes a function of both frequency and input power.

Abstract: An high power microwave expander is provided which decreases the rise time of rf pulses. The expander is a transmission line in which internal conductors are separated and tapered to provide a spark gap with high isolation characteristics at low power. The arcing threshold of the spark gap can be adjusted by varying the internal pressure of the transmission line, injecting a gas such as helium into the transmission line and by providing free electrons in close proximity to the spark gap.

Abstract: A microwave rf envelope generator or pulse shaper has a main waveguide with two opposing branches connected in shunt to the main waveguide and are terminated with variable positionable shorts. The characteristic impedance of the shunted combination of the two branches equal one half the characteristic impedance of the main waveguide. An incident rf pulse applied to an input of the main waveguide is transmitted to a four way junction formed at the intersection of the two branches. The incident pulse is divided at the junction. Divided pulses are then transmitted down each of the branches and to an output of the main waveguide. The pulses traveling down each branch will have their phases shifted when they are reflected by the variable positionable shorts. The lengths of the branches are adjusted by the variable shorts so that the phase of the reflected and inverted pulses will cancel the trailing portion of the pulse transmitted out towards the output of the main waveguide.