Electronic device and method for adjusting output power of radio frequency signal to be output to antenna

A method and electronic device are provided for adjusting an output power of an RF signal to be output to an antenna, based on a proximity of an object and a shape (or configuration) of the electronic device. The electronic device may include a proximity sensor, an antenna corresponding to the proximity sensor, a power amplifier corresponding to the antenna, and a processor configured to control the power amplifier to output a first RF signal having a first output power to the antenna, identify the antenna corresponding to the proximity sensor, based on proximity of an object being detected by the proximity sensor, identify, using a power table configured for the antenna, a second output power corresponding to a shape of the electronic device and the proximity of the object being detected, wherein the second output power is different from the first output power, and control the power amplifier to output a second RF signal having the second output power, to the antenna.