Abstract: A formula of the horizontal directivity of the circular array which is consisted of elements with arbitrary directivity was derived.
The diretivity patterns of circular array which is consisted of elements without back radiation such as the compound bar was disussed in detail. The effect of various paramen-ters on directivity was given.
For the circular array consisted of the point elements, the following conclusions were obtained:the circular pattern was obtained more easily using odd number of elements than using even number of elements; when the product of the radius of array and the wave number approches to the zero point of zero order Bessel function, the fluctuation of the directivity pattern increases significantly and the transmitting sensitivity or the receiving sensitivity of the array decreases significantly.