Abstract: In this paper the element pattern-steerable adaptive circular arrays are described. The element consists of three-orthogonal dipoles. All the element radiation patterns in the array can be steered by a set of weightings to point to an arbitrary specified direction. Thus a high directional beam in an arbitrary directional position within a 3-dimensional space can be formed to capture a desired signal effectively. On the above basis the techniques of the adaptive linear array of uniformly spaced isotropic element investigated by W.F.Gabriel are generalized to the special topic of the element patternsteerable adaptive circular arrays by means of the concept of equivalent interference source. This paper discusses following theoretical aspects of the said arrays: the array farzone radiation field, the direction-controlled weighting factors of the element radiation pattern, the covariance matrix of the set of system inputs, the orthogonal resolution of the array output pattern, the transient characteristic for total output noise power of the array system.