3D tag with improved read range for UHF RFID applications using Additive Manufacturing

In this paper a 3D tag antenna geometry is proposed for UHF RFID systems. Two antennas were built over different dielectric materials with similar properties using both Direct Digital Manufacturing and traditional photolithography and copper etching. The impedance matching between the antenna arms and the passive RFID integrated circuit was accomplished with the H-slot matching technique with a simulated 10 dB return loss bandwidth that allows the tag to operate in the American and European ISM RFID bands of 902-928 MHz and 864-868 MHz, respectively. The antennas were compared to commercially available tags in size, weight and read distance, showing a read range improvement of 136% (for a threshold power of 30 dBm) with respect to the best tag tested. A reduction in length of 78 % with respect to a planar 2D model was also achieved. The radiation patterns were measured, showing an omni-directional beam pattern.