A multi-channel transmit/receive antenna device or arrangement for use in a magnetic resonance imaging (MRI) system includes a POWER monitoring unit. To ensure that a specific absorption rate of a patient is not exceeded and transmitted POWER levels and reflected POWER levels ON channels for a plurality of coils and/or coil segments are monitored. Each coil/coil segment is supplied with RF transmit signals with different amplitudes and/or phases and/or waveforms and/or POWER levels.