Further progress in pulse sharpening using ferrite lines

When a sufficiently large amplitude electromagnetic pulse travels along a transmission line containing a layer of ferrite, the interaction of the magnetic nonlinearity of the ferrite with the pulse can result in the development of an extremely steep pulse leading edge. Ferrite-loaded coaxial lines are used as an extremely robust means of generating electrical pulses with rise-times of <500 ps and voltages of 10 kV and above for applications including ultra-wide-band radar, Pockels cell drivers, laser triggering, and streak camera gating. The authors aim to clarify the physical processes which govern the pulse sharpening effect. Theoretical work has included the development of a time-stepping computer code which incorporates the static and dynamic magnetic characteristics of the ferrite, and predicts the development of waveforms propagating along ferrite lines. This code has already enabled the design of transmission lines with substantially improved performance (<200 ps rise-time). Practical problems presently also being addressed include minimisation of line output pulse timing jitter, line cooling, pulse measurement, and the design of high performance pulse interconnections between system components