SVD-Based Hardware Concept to Drive N Transmit Elements of a Phased Array Coil with M≤N Channels for High Field MRI

Guillaume Ferrand¹, Michel Luong¹, Martijn A. Cloos^1,2, Alain France¹, Alexis Amadon², Nicolas Boulant², Luc Darrasse³

In high field MRI, a phased array coil comprising a large number of transmit elements appears more attractive with respect to local SAR reduction and to B1 inhomogeneity mitigation using parallel transmission. However, if each element were driven by a dedicated channel consisting of a concatenation of signal modulator and high power amplifier, the system cost would increase linearly with the number of transmit elements. It would be the same for the acquisition time of B1 maps necessary for parallel transmission. Here, we propose a new hardware scheme based on the singular value decomposition (SVD) to drive N elements with M channels, where M ≤ N. The proof of concept is provided by numerical simulations of the whole process.