| 摘要 |
An antenna coupling device for transforming a manhole metallic cover use in municipality sewer system as a bidirectional radio frequency antenna without making any physical modification to the said manhole metallic cover. More specifically, an antenna coupling device located within one of the ventilation hole of the manhole cover that capacitively and inductively couple within the near-field to the ventilation hole surrounding metal that further couple to the entire manhole metallic upper and lower metal surface. Such coupling method resulting in an overall antenna radiation pattern and gain that is much less sensitive to the manhole metallic cover upper surface accumulation of snow, salty water and debris conditions. |
