The Electrically Small Dipole Loop

Abstract

A square loop, with feed at the center of one side, can be combined with a dipole, where the dipole is parallel with the loop axis, and shares the feed point; see Fig. 1. With the dipole length twice the loop side, there will be a frequency where the dipole reactance and loop reactance are equal and opposite. It has been suggested [1,2] that this loop dipole together with a second loop dipole fed 90 deq. out of phase provides broadband performances, in fact a Q equal to zero. The plane of the second loop dipole is normal to the plane of the first loop dipole. Because stored energy is an inevitable feature of electrically small antennas, the loop dipole is examined to determine bandwidth capabilities