Mutual impedance of two thin, linear, coplanar, perpendicular dipole antennas

Abstract

A general expression was developed for the mutual impedance of two thin, linear, coplanar, perpendicular dipole antennas using the method of vector potential and integral solution. Four new types of integrals, termed as Affiliated Integrals, were introduced and tabulated in this work using an I. B. M. 709 digital computer. The expression for the mutual impedance was derived containing these integrals. The main advantage of this approach lies in the fact that once these integrals are tabulated, the value of the mutual impedance can be calculated for any antenna length, vertical separation and horizontal separation. The theoretical results were checked by experimental measurements for different antenna lengths at a frequency of 250 megacycles per second. The antennas were made from one-eight inch diameter bronze rods. A reasonable agreement was found between the calculated and experimental values. To check the accuracy of the Affiliated Integrals, the value of the mutual impedance was calculated by numerical integration using an I. B. M. 709 digital computer. This value was then compared with that obtained by the general expression and the Affiliated Integrals. They show good agreement. Differences between the theoretical and experimental results were discussed and suggestions made for future work in this area.