Closed slot antenna applied to metal machine shell and manufacturing method of closed slot antenna

The invention discloses a closed slot antenna applied to a metal machine shell. The closed slot antenna comprises the metal machine shell, an antenna exciter and a plastic part; the metal machine shell comprises a closed slot structure and an installation location corresponding to the closed slot structure, and is used for electrical grounding; the antenna exciter comprises at least one fine-tuning metal unit, a feed-in part and a grounding part, and the antenna exciter is arranged at the installation location and used for cooperating with the closed slot structure of the metal machine shell so as to excite the closed slot antenna; the plastic part is obtained through embedded injection molding, the plastic part wraps at least one part of the antenna exciter, and the plastic part is provided with at least one fine-tuning window used for expose the fine-tuning metal units of the antenna exciter; the fine-tuning metal units are used for determining the degree of the fine-tuning metal units needing to be machine