Systems, methods, and devices are provided for detecting the presence of an object near an electronic device. A radio frequency (RF) system of an electronic device may include a first circuit that includes one or more transmission paths for transmitting a reference signal external to the electronic device. The RF system may include a second circuit that includes one or more receiving paths for receiving a reflection signal based on the reference signal. The RF system may also include a processor that may instruct the RF system to perform a comparison between the reference signal and the reflection signal, determine whether the object is in proximity based at least in part on whether comparison results exceed a comparison threshold, and decrease power output by the RF system below the comparison threshold.