A novel array of elliptic ring radiators

An array of elliptic ring radiators is proposed which generates a fan-type beam with controllable sidelobe levels. Such an array has applications in specialized acoustic systems such as sidescan sonars, sonars 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 generated 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 equivalent linear array. This approach benefits from existing design techniques developed for linear arrays. It requires only simple matrix operations and does not involve any optimization. The design examples presented demonstrate that a fan-type beam with sidelobes suppressed to more than 40 dB in all possible directions is achievable.<
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