An access control device including a credential reader circuit configured to enter a standby mode, awaken from a standby mode, and receive data from a nearby credential. The access control device further includes a credential detection circuit having a memory configured to store program instructions, an antenna, and a processor electrically coupled to the antenna and to the credential reader circuit, wherein the processor is configured to execute the stored program instructions to: transmit an interrogation signal, receive a reflected interrogation signal with the antenna, transmit an activation signal to the credential reader circuit in response to the received reflected interrogation signal wherein the reflected interrogation signal includes I and Q values, receive a false detection signal from the credential reader circuit, and adjust at least one of the I and Q threshold values of the reflected interrogation signal.