The resonant circular array of electrically short elements

Different resonant distributions of current in circular arrays with N=60, 72, and 90 elements are investigated theoretically with the method of symmetrical components and a two-term representation of current in each element. The arrays studied have only one driven element. The remarkable results—which are displayed in a sequence of graphs—indicate that the relative currents in the elements can be distributed in triplets, triplets alternating with singlets, two independent sets of singlets, or one set of singlets. The driving-point impedance of this last distribution is a pure resistance, the Q of the 90-element array is over 30 000, and the half-power beamwidth of each of the 90 sharp peaks in the power pattern is 2°.