A NOVEL ARRAY OF ELLIPTIC RING RADIATORS

A novel array of elliptic ring radiators is proposed which generates a fan-type beam with controllable sidelobe levels. Such an array has ap plications in specialized acoustic systems such as sidescan sonars, so nars for fish finding and stock assessment, obstacle avoidance systems , and others. Two possible approaches to the design are presented. One approach utilizes a mapping which transforms a radiation pattern gene rated by a circular ring array to that of an elliptic ring array. This approach takes advantage of methodologies developed for the design of circular ring arrays.-The other approach uses the concept of an equiv alent linear array. This approach benefits from existing design techni ques developed for linear arrays. It requires only simple matrix opera tions and does not involve any optimization. The design examples prese nted demonstrate that a fan-type beam with sidelobes suppressed to mor e than 40 dB in all possible directions is achievable.