A helical phase shifter for VHF

A helical phase shifter for very high frequency (VHF) signal transmission has been designed. The phase shifting device operates on the principle of coupled helices and the energy is electromagnetically transferred to the inner helix, producing a non-contacting unity transmission device. The electric design of the phase shifter has been developed according to the theory proposed by Kompfner, along with a team of researchers. The theory states that complete undirection power transfer occurs, when the helices are contrawound and the phase velocities on each helix are equal and coupled over some appropriate length. Another researchers studied the wire diameter of the phase shifter, demonstrating that the ration of the wire size diameter to the pitch needs to be equal to 0.33 for least attenuation.