Cost-Effective Broadband and Compact Patch Antenna Based on Ball Grid Array Packaging for 5G NR FR2 Band Applications

This brief introduces a compact, cost-effective broadband patch antenna based on ball grid array (BGA) packaging technology for 5G millimeter wave new radio (NR) FR2 band application. Based on the low-cost FR-4 substrate and single-layer configuration, the patch antenna achieves an ultra-low cost, which is attractive for large-scale 5G millimeter-wave array applications. Parasitic patches are added to the antenna to obtain broadband impedance bandwidth. To further reduce the antenna size and eliminate bulky connectors, solder balls are added to form a BGA package with connectorless interconnects. Consequently, the proposed antenna element achieves a compact size of 5.2 mm x 3.2 mm x 1.4 mm. Antenna elements and 1 x 8 array prototypes have been fabricated and verified. The measurement results show that the proposed antenna element has a -10 dB bandwidth of 56.1% (20-35.6 GHz), fully covering the 5G millimeter wave n257 (26.5-29.5 GHz), n258 (24.25-27.5 GHz), and n261 (27.5-28.35 GHz) bands. The maximum realized gains of the antenna elements and the 1 x 8 array prototype are 7.2 dBi and 13.9 dBi, respectively.