A receiver of an object finder includes an antenna to receive a signal from a transmitter associated with the receiver, a PIN diode having a first terminal coupled with the antenna, and having a resistance that increases as a current flows therethrough decreases, and vice versa, a variable resistor coupled with the first terminal of the PIN diode to control the amount of a current flowing into the PIN diode, and a radio frequency integrated circuit (RF IC) having a first pin electrically coupled with second terminal of the PIN diode to receive the signal from the antenna via the PIN diode.