free space path loss in simulink

greetings
I am working on the simlation of RFID system ,the problem that i am encountering is that my transmitted baseband signal is real and when i give it as input to the free space path loss block in simulink it gives me an error indicating that only complex signal must be given as an input to free space path loss ,i dont know how to fix the problem, can somebody give me a hint.

it's so simple!you must apply a real to complex block.