Design Of Oversized Twts With Photonic Band-Gap Structures

The challenge in manufacturing Traveling Wave Tubes (TWTs) at high frequencies is that the sizes of the structures scale with, and are much smaller than, the wavelength. This requires advanced nano-machining techniques or sheet-beam devices and puts strict limits on the peak output power that can be safely handled by the devices. Furthermore, the diameter of the electron-beam tunnel limits the amount of beam current, requires high magnetic fields for beam compression and creates difficulties in alignment.