Peru is currently in a high-risk zone because it is prone to natural disasters, such as earthquakes. Earthquakes affect infrastructures that are harmful to the population that may be trapped inside. According to the INEI (Instituto Nacional de Estadística e Informática), 90.6% of households in Peru have at least one member who has a mobile phone, which facilitates the searching of people in cases of natural disasters through the detection of the radiofrequency of the mobile phones. The following work consists in the Design of a Radio Frequency Detection System for Mobile Phones capable of capturing the phones transmission signal when they are connected to the base antenna, because it will be applied when an earthquake happens thus minimizing the time search for people who suffer accidents inside their buildings and get trapped in the rubble.