A mixing inlay (102) is provided which includes a first radiating element (110a), a second radiating element (110b), and a non-linear mixing component (112) connected between adjacent end portions (114a, 114b) of the first and second radiating elements. The mixing inlay is configured to receive a first exciter signal having a first frequency and a second exciter signal having a second frequency, and in response, to radiate a mixing product signal produced by the mixing inlay from the first and second exciter signals. A conductive parasitic element (116) is disposed within a near field of the re-radiating transponder. A distance provided between the conductive parasitic element and the radiating elements is varied over the length of the conductive parasitic element to enhance a sideband signal generated by the mixing inlay.