Top-pivoting underwater RFID antenna assembly

摘要

An underwater top-pivoting antenna assembly (or array thereof) suitable for subsurface RFID tag interrogation in flowing water such as a river. In preferred embodiments, the antenna interrogates RFID tags implanted in aquatic species. The antenna resides in an elongate antenna housing whose cross-sectional shape is preferably a symmetric hydrodynamic teardrop shape. When the assembly is deployed in water with an upper end thereof suspended above a lower end, the upper end of the housing is linked to a pivot/swivel mechanism such that when the pivot/swivel mechanism is held substantially stationary with respect to the water flow, the lower end of the housing is free to rotate generally about the first end, including in a substantially vertical plane parallel to the water flow direction. The length of the antenna housing is advantageously selected to enable the antenna to monitor for signals across substantially the entire water depth.

主权项

1. An underwater top-pivoting antenna assembly for subsurface RFID tag interrogation in flowing water, the water having flow in a known water flow direction, the water flowing over a bottom bed, the water further having a nominal water depth above the bottom bed, the antenna assembly comprising:
an antenna, the antenna suitable for RFID tag interrogation; an elongate antenna housing, the antenna housing including a housing length separating first and second ends thereof, the antenna resident in the housing, the housing length having a symmetric hydrodynamic teardrop cross-sectional shape, the housing length further selected to enable the antenna to monitor for signals across substantially all of the water depth; and a pivot/swivel mechanism linked to the antenna housing at the first end thereof, such that when (1) the first end is positioned in the water flow above the second end and (2) the pivot/swivel mechanism is substantially immobilized with respect to the water flow, the pivot/swivel mechanism permits the second end of the antenna housing to rotate freely, responsive to water flow, about the first end in a substantially vertical plane parallel to the water flow direction.