Design of multi limb phase shifter

Plasma is a variable load. The impedance of the plasma varies over a wide range. This requires impedance matching with RF generator. The impedance of the generator is normally 50-Ohm. The impedance matching requires stub tuners and phase shifter. Multi limb phase shifter is one of the RF high power transmission line component that will be used for impedance matching. Multi limb phase shifter is a phase shifter where more than one arms are used for phase variation in a single stroke. This gives the advantage that with the same variation of length multiple phase shifts is achieved. Keeping the moving length small for one section makes the movement easier. Four limbs are being used here. The length of each limb is kept as 500 mm, so the overall length variation of 2000 mm is achieved. Here we present the design details of this Multi limb phase shifter. The Phase Shifter is of 9 3/16'' size and is made up of ETP copper. The system is as per EIA standard and is of 50-Ohm type. The system will be motorized.