Asymptotic Analysis on Directivity and Beamwidth of Uniform Circular Array

In this letter, the directivity and beamwidth of uniform circular array (UCA) are asymptotically analyzed with respect to the number of antenna elements and the size of UCA. In our analysis, we assume that beamforming is done on the azimuth plane by using UCA. Then, we show that the maximum directivity on the target direction increases with Θ(N
^3/2
), where N is the number of antenna elements in UCA. In addition, vertical and horizontal beamwidths decrease with Θ(1/√N) and Θ(1/N), respectively.