In this project, the problem of synthesizing a finite frequency H-infinity decentralized controller has been investigated. The cases of dynamic, static, and PID output feedbacks are considered. The focal points of the research lie on that the controllers are subject to any structural constraints, and in addition, the order of a dynamic controller can be assumed to be reduced-order or full-order. A particular transformation has been proposed that converts the original problem (with controller subject to any structural constraint) into the problem of designing a block-diagonal controller. The equivalence of the synthesis problems has been shown. Solvability conditions for synthesizing the controllers were derived in terms linear matrix inequalities (LMIs). Numerical simulation demonstrates the effectiveness of the proposed method.