The effects of asymmetry on the operation of the Van Veen Loop

Practical implementations of the Van Veen Loop, or Large Loop Antenna (LLA), necessarily contain imperfections, especially those due to finite mechanical tolerances. We examine the effects on performance of non-commensurate constituent transmission lines and unequal terminating resistors in the internal network of an LLA. It is shown that the electric field rejection of the LLA is somewhat insensitive to these errors, especially in the lower portion of its operating frequency range. Unfortunately, it is also shown that the effects of these two imperfections on the validation factor are very similar to one another and to those caused by an imperfect current transformer. Thus, for a practical LLA, it can be difficult to trace the source of the deviation of the validation factor from the ideal behavior. Suggestions are given for minimizing the effects of asymmetry in the practical LLA thereby enhancing the electric field rejection.