Guclu Ceylan Celil, Boskamp Ed, Zheng Tsinghua, Becerra Ricardo, Blawat LeRoy
General Electric Medical Systems, MR Engineering, Milwaukee, Wisconsin 53188, USA.
J Magn Reson Imaging. 2004 Feb;19(2):255-8. doi: 10.1002/jmri.10449.
To improve preamplifier decoupling in a quadrature phased-array coil using a new quadrature combiner configuration.
A commercial six-element quadrature cervical-thoracic-lumbar (CTL) coil was used on a 1.5 T GE Signa Lx Scanner. The new combiner configuration is designed based on the fact that when one compares the amount of flux linkage of two loops with butterfly elements separated by the same distance, the loop elements have much higher coupling than the butterfly elements.
The results are demonstrated using an imaging-based element coupling measurement method. The new quadrature combiner configuration has introduced an approximately -8dB improvement in preamplifier decoupling.
One-dimensional quadrature phased arrays can be built even if the preamplifier is not integrated in the coil. If the combiner is placed between the coil and the preamplifiers, the butterflies should be on the high impedance side of the quadrature combiner. The loops should see the low input impedance of the preamplifiers.
使用一种新的正交组合器配置来改善正交相控阵线圈中的前置放大器去耦。
在1.5T的GE Signa Lx扫描仪上使用商用六元素正交颈胸腰（CTL）线圈。新的组合器配置是基于这样一个事实设计的，即当比较两个由相同距离隔开的蝶形元件的环路的磁链量时，环形元件的耦合比蝶形元件高得多。
使用基于成像的元件耦合测量方法展示了结果。新的正交组合器配置在前置放大器去耦方面带来了约8dB的改善。
即使前置放大器未集成在线圈中，也可以构建一维正交相控阵。如果组合器放置在线圈和前置放大器之间，蝶形元件应位于正交组合器的高阻抗侧。环形元件应看到前置放大器的低输入阻抗。
