E. V. Volkhonskaya - Dr.Sci. (Eng.), Professor
E. V. Korotey
D. V. Kuzhekin

The influence of mismatch between the elements of log-periodic antenna GSM-900 and the exciting feeder was described in this work. Electromagnetic field in a distant zone, directional diagrams in two principal planes and polarization pattern of the antenna was determined on the basis of the developed amplitude-phase distributions of terminal currents in elements of log-periodic antenna calculation procedure, which considers their interaction by means of exciting feeder. The main beam width, coefficient of the directed action and ellipticity coefficient were determined on the basis of the received curves. The analysis of the model curves allowed to conclude that directed and polarizing properties of the antenna slightly change in operation frequency range. Practical research of antenna main beam width, coefficient of directed action and ellipticity coefficient were carried out for the purpose of modeling results confirmation. The comparison of practical and theoretical results showed satisfactory accuracy. Thus the developed amplitude-phase distributions of terminal currents in elements of log-periodic antenna calculation procedure and used restrictions are adequate.