Wideband Antennas on Thin-Film Packaging Substrates for 140 GHz 6G Applications

In this work, we present the development of wideband single element and 1x5 elements patch antenna array on thin Ajinomoto’s Build-Up Film® (ABF) for 140 GHz 6G applications. This thin-film packaging substrate is chosen for the design and fabrication of 6G antennas in the sub-THz band because of its very good RF properties and advanced design rules compared to standard PCB technology processes. Since large bandwidths are required for high-speed 6G communication, we applied a multi-resonance method using U-slot configurations inside the patch to increase the bandwidth of the antennas. To minimize the side-lobes in the array, we implemented the Tschebyscheff-filtering method to the individual array elements. The optimized antennas were fabricated. Finally, both geometrical and electrical parameters (e.g. return losses and radiation patterns) of the fabricated antennas were measured. Only minor process deviations (< 2.5 %) were observed. The measured single element and 1x5 elements series-fed U-slot patch antennas achieved wide impedance bandwidths of 13.2 GHz and 15.2 GHz, respectively. The measured peak gain of the array is 12 dBi.