发明授权
US4725782A Antenna structure for exciting and/or receiving RF fields in an NMR
tomography apparatus
失效
在NMR层析成像装置中用于激发和/或接收RF场的天线结构
- 专利标题: Antenna structure for exciting and/or receiving RF fields in an NMR tomography apparatus
- 专利标题(中): 在NMR层析成像装置中用于激发和/或接收RF场的天线结构
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申请号: US36797申请日: 1987-04-10
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公开(公告)号: US4725782A公开(公告)日: 1988-02-16
- 发明人: Ralph Oppelt , Wilhelm Duerr
- 申请人: Ralph Oppelt , Wilhelm Duerr
- 申请人地址: DEX Berlin and Munich
- 专利权人: Siemens Aktiengesellschaft
- 当前专利权人: Siemens Aktiengesellschaft
- 当前专利权人地址: DEX Berlin and Munich
- 优先权: DEX3616705 19860520
- 主分类号: A61B10/00
- IPC分类号: A61B10/00 ; A61B5/055 ; G01R33/32 ; G01R33/34 ; G01R33/422 ; G01R33/20
摘要:
An antenna structure for exciting a substantially homogeneous magnetic RF field and/or for receiving RF signals in a nuclear magnetic resonance tomography apparatus includes a hollow cylindrical conductor sheath which is substantially transmissive at low frequencies for gradient magnetic fields, a number of conductor units within the conductor sheath, each conductor unit including at least one conductor element, and RF reflector disposed at the end faces of the antenna structure and an external energy feed or reception device. In this antenna structure, the current drop which increasingly occurs toward the end faces of the antenna structure is largely compensatable by shaping the electrically conductive cross-section of the conductor units so as to decrease symmetrically from an axial center of the antenna structure moving toward the end faces of the structure. The conductor units thus have a largest cross-section at a center of the antenna structure, and a smallest cross-section at the end faces.