Stephen E. Ogier1, Shaihan Malik1, and Joseph Hajnal1,2
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
RF networks have been investigated that allow the sharing of
transmit power between channels. These have the potential to increase the
maximum transmit field a given coil and set of RF power amplifiers can produce.
Four proposed structures for exciting two coil elements with
two RFPAs. A Conventional pTx excitation with one dedicated amplifier per
coil. B Power sharing with a 90° hybrid coupler. C Power sharing with
a 90°
hybrid coupler and phase shifter. D Power combination with a Wilkinson power
combiner.
Top row is a shim well-suited to power sharing and bottom
row is a shim poorly-suited. Left column shows RFPA output power for the
standard system and system with the power sharing network. The right column
shows coil drive power levels for the standard system and power sharing
network.
