High-Gain Endfire Array Antenna Using a Stripline-to-Radiating via Monopole for 5G mmWave

This letter presents the design of a 1 × 8 linear array antenna based on a novel stripline-fed radiating-via monopole (RVM) structure for 5G millimeter-wave (mmWave) wireless applications. The array comprises eight RVM elements, each sandwiched between two metallic plates. Each element features a vertically oriented radiating via, directly fed by a stripline, with symmetrically arranged ground vias to enhance impedance matching, suppress mutual coupling, and enable endfire radiation. The proposed RVM antenna achieves a high radiation efficiency and gain due to its simplified and tightly confined feeding mechanism. The fabricated array antenna has a compact footprint of 34.1 mm × 47.6 mm, and operates within 24 GHz to 30 GHz (22.6%), achieving an average gain of 15 dBi and low cross-polarization levels.