Quadrature RF array using High Impedance concept for improved transmit RF field B1 efficiencyat 7 Tesla.

Decoupling performance between coil elements is one of the factors that limits the transmit B1 field efficiency and SNR. However, mutual coupling between coil elements is an inevitable electromagnetic interaction that alters the isolated current distribution and impedance of individual elements. In contrast to linear arrays, decoupling challenge of quadrature arrays is more pronounced. In the pursuit of low inter-coupling, a high-impedance technique is adopted. A quadrature hybrid coil composed of loop and microstrip is used in a planar configuration. By employing the high-impedance method, sufficient decoupling between quadrature coils is obtained without the use of additional decoupling network.