This article addresses the issue of adaptive intelligent asymptotic tracking control for a class of stochastic nonlinear systems with unknown control gains and full state constraints. Unlike the existing systems in the literature in which the prior knowledge of the control gains is available for the controller design, the salient feature of our considered system is that the control gains are allowed to be unknown but have a positive sign. By introducing an auxiliary virtual controller and employing the new properties of Numbness functions, the major technique difficulty arising from the unknown control gains is overcome. At the same time, the log-type barrier Lyapunov functions are introduced to prevent the violation of the state constraints. What's more, neural networks' universal online approximation ability and gain suppression inequality technology are combined in the frame of adaptive backstepping design, so that a new control method is proposed, which cannot only realize the asymptotic tracking control in probability, but also meet the requirement of the full state constraints imposed on the system. In the end, the simulation results for a practical example demonstrate the effectiveness of the proposed control method.

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This paper presents a novel method to evaluate radiation energy and mutual coupling in multimode antennas. Based on the theory of characteristics mode, how much each mode occupies the radiation and the mutual coupling from each feeding port is calculated with the modal energy occupied coefficients. Furthermore, the linear transformation of feeding network in multimode antenna system has been adopted to complete the modal-based method. Then, this method is utilized to analyze and decrease the mutual coupling between feeding ports. Hence, a hexagonal wideband antenna is proposed with its evolution process and measured to validate the proposed method. The presented hexagonal antenna is a four-port multimode antenna consisting a planar hexagonal plate, vertical tapered baluns, and feeding network at the ground plane. The whole antenna works in 3-6 GHz and all its four ports are well matched with high port-to-port isolation.

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