Arrays of Unequal and Unequally-Spaced Dipoles with Application to the LOG-Periodic Antenna

摘要

Curtain arrays involving dipoles of both unequal heights and with unequal spacings are examined. Theoretical values are computed using a modified three-term current theory in which the method of driving-point fitting is replaced by that of three-point fitting. A new experimental technique is developed for measuring the self- and mutual admittances of the dipole elements in the curtain arrays. The theory is then used for computing the characteristics of a five-element log-periodic dipole antenna. Accurate measurements are also made with an equivalent model using a coaxial-line feeding arrangement. Finally, a twelve element L-P dipole antenna is critically examined using the theory. Some very interesting and important basic properties of the L-P antennas are brought into light. The performances of the L-P dipole antennas can be clearly demonstrated in terms of the basic properties. (Author)