When the elements of the folded dipole and the Alford loop are combined, the desired
impedance match can be achieved using the properties of a folded dipole, and the desired radiation pattern can be reached from the Alford loop shape.
A small amount of reflected amplitude, an indication of a good
impedance match, would be a large, negative number in dB.
With this feed configuration, a good
impedance match has been achieved for a narrow slot, and an impedance bandwidth of approximately 20 percent has been obtained.
The limiting conditions of
impedance match are defined by Equations 10 for an infinite number of matching elements, and by a chart presented in Fano [5] for various finite numbers of matching elements.
Moment method analysis of a pair of simple 90[degrees] mitered square wave-guides demonstrates excellent differential phase shift and amplitude over more than an octave bandwidth, even though the
impedance match of each bend is not optimum.
