A capacitive sensor device for a handheld radio transceiver for estimating a specific absorption rate (SAR) can be coupled with at least one first electrode, wherein during the operation of the handheld radio transceiver the first electrode is at the same time a sensor electrode of the capacitive sensor device and an antenna of the handheld radio transceiver. Moreover a handheld radio transceiver with such a capacitive sensor device can be provided. Moreover, a method can be provided for adjusting a transmission power of a handheld radio transceiver, wherein an approach of an object to the handheld radio transceiver is detected and wherein depending on the detected approach the transmission power of the handheld radio transceiver is increased or reduced.