Effect of pitch variation on the linearity of helix TWTs

The effect of variation in the pitches of different sections of a helix slow wave structure (SWS) on AM/PM and third order intermodulation distortion (C/3IM) is studied. A 2-section SWS operating in the frequency range, 10.5-12.3 GHz is considered. AM/PM curves at saturation are plotted and C/3IM values at saturation are tabulated for different pitch values.