In this contribution, we investigate the effect of a resonant high-impedance shield as a part of a birdcage coil for human brain imaging at 7 T. On a homogeneous phantom, it was shown that the loading of the birdcage coil to the sample can be enhanced by replacing a conventional copper shield with the high-impedance boundary with frequency-dependent surface impedance. To demonstrate this effect, we perform a numerical simulation of an extended birdcage coil with the high-impedance shield. The extended coil is much more comfortable for a patient and creates a lower local SAR. It has been shown that the extended coil equipped with the high-impedance shield has the same efficiency as a standard-size coil with the copper shield.
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