A method and system for determining bale properties of crop material bales includes transmitting a first microwave signal through a bale of crop material located within an agricultural baler at a first frequency and transmitting a second microwave signal through the bale of crop material at a different second frequency and calculating, with at least one computing device, a phase angle displacement between the first and second microwave signals and determining, with the at least one computing device, a bale property of the bale of crop material based at least in part on the calculated phase angle differential.