The Specific Absorption Rate (SAR) is usually measured using electric field probes based on dipole antennas, loaded with radio frequency (RF) detector diodes and connected to differential amplifiers through high-impedance transmission lines. The most common configuration consists of three mutually orthogonal electric short dipole antennas, loaded with a fast switching detector, providing broadband characteristics. In this work, we describe the measurement of the SAR with a sensor based on a single dipole antenna. It is shown that this reduces the complexity of the system without compromising the accuracy and frequency response. The probe is tested by measuring the SAR for a dual-band Planar Inverted-F antenna.