Elimination of Phase Shifts between the Currents in Two Antennas

If two antennas (vertical radiators) are fed through transmission lines from a common radio-frequency supply, then phase shifts between the currents in these antennas will occur if one antenna varies in capacity or resistance. This will result in a change of the horizontal radiation pattern. As shown in the following paper these phase shifts can be eliminated by a certain method of tuning the antenna circuits. The degree of phase compensation attainable, however, depends on the attenuation of the transmission line. Compensation of phase shifts is also possible if an artificial line is inserted at the sending end for reasons of making the effective electrical length of the transmission line any value desired. The results of the experimental investigation were found to be in good agreement with the theoretical analysis.