| 摘要 |
An antenna device for coupling to a magnetic high-frequency field in apparatus for nuclear spin tomography, includes at least two conductor sections of predetermined length which extend on an imaginary cylinder surface parallel to the direction of the axis of the imaginary cylinder and are arranged for current flow in opposite directions when one end of each of the sections is connected to an external device, a tubular enclosure arranged at a predetermined distance concentrically with respect to the imaginary cylinder surface surrounding the conductor sections, the enclosure being at least largely permeable to low frequencies for magnetic gradient fields, containing electrically highly conductive material and adapted to be connected to the external device, the tubular enclosure extending in the axial direction beyond the end of the conductor sections by a predetermined amount so as to form a circular waveguide antenna with a periodic wave propagation, the coupling elements of which are the conductor sections, and reflectors terminating the other ends of the conductors to reflect waves of the high-frequency field so that a high-frequency field oscillating in phase is formed by the tubular enclosure and the conductor sections.
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