A mop includes a first section having a first side, a second section having a second side, and an embedded, semi-permeable layer disposed between the first and second sections to manage an amount of liquid flowing from the first side to the second side. A tiecoat metal layer having a thickness of between 5 and 70 is disposed on the first side of the copper layer. The weighted received signals accurately replicate the antenna array response in the far field, including electromagnetic glint caused by the platform on which the antennas are mounted, and are stored in complex voltage form as a calibration table for the array. The vending machine receiving, from a customer, a selection of a first product that the at least one inventory group includes.