Microwave characterisation of polylactic acid for 3D‐printed dielectrically controlled substrates

In this study, the characterisation of three‐dimensional (3D)‐printed substrates in terms of relative dielectric constant and loss tangent by using the T‐resonator method is proposed. In particular, after the theoretical formulation of this method, the T‐shape structure has been realised and its effectiveness in characterising also 3D‐printed substrates in the frequency range between 800 and 5000 MHz has been experimentally demonstrated. Therefore, the T‐resonator has been used to perform the microwave characterisation in terms of both dielectric constant and loss tangent of 3D‐printed polylactic acid substrates when varying the infill percentage. Obtained results have been first summarised and discussed, and then used to realise an example of 3D‐printed ultra‐high‐frequency radio‐frequency identification tag, thus demonstrating the suitability of 3D‐printable materials to be used as dielectrically controlled substrates for low‐cost and high‐performing electromagnetic applications.