Empty Substrate-Integrated Waveguide-Fed Patch Antenna Array for 5G Millimeter-Wave Communication Systems

This letter presents a microstrip patch antenna array fed with a low-loss and highly efficient feeding structure called empty substrate-integrated waveguide (ESIW). The proposed antenna array targets 5G wireless communication systems operating at 28 GHz. The antenna array consists of 4 × 4 radiating patches, where every four radiating elements are grouped together forming a 2 × 2 subarray and each of the subarrays is fed by ESIW feeding network by aperture coupling. The experimental results demonstrate good agreement with the simulated results, offering a wide | S 11| < −10 dB bandwidth of 12.4%, i.e., 26.5–30 GHz. A peak gain of 18.2 dBi and a high efficiency of about 91% are achieved using the proposed structure. Furthermore, the low-profile substrate of the ESIW feeding structure makes seamless integration of the proposed antenna array with the millimeter-wave front end. The advantages, such as low fabrication cost and high efficiency, make the proposed antenna array a suitable solution for millimeter-wave 5G wireless communication systems.