An FR4-Based Miniaturized High-Efficiency Double-Sided SISL Longitudinal Slot Antenna Array for 5G Millimeter-Wave Applications

This communication presents a miniaturized, high-gain, and high-efficiency longitudinal slots antenna array, designed using double-sided substrate integrated suspended line (DSISL). The feeding structure employs double-layer wiring technique, connecting through metalized vias to minimize dielectric loss. By integrating periodic short-stubs transmission lines, a novel compact feeding structure is leading to a miniaturized size. Moreover, the short-stubs can excite longitudinal slots to generate radiation. The subarray and array are fabricated to using multilayer printed circuit board (PCB) technology with low cost FR4. The measured impedance bandwidth for the sub-array and array is 25.5-31.4 GHz (20.7%) and 25.8-31.3 GHz (19.3%), respectively. The maximum measured realized gain is 14.5 dBi and 20.2 dBi, with radiation efficiency of 95% and 93%, respectively. These findings validate the array has wideband, high-gain, and high-efficiency and potential for 5G millimeter-wave systems.