Wide scan angle multibeam conformal antenna array with novel feeding for mm-wave 5G applications

This paper presents a low-profile wide scan angle multibeam conformal antenna array system with a novel feeding network for $28$ GHz mm-wave 5G applications. The proposed antenna system utilizes two conventional branch-line couplers as its beamforming network. A novel feeding technique is applied to generate $7$ beams with these couplers that are usually capable of generating $2$ beams. The proposed solution provides a wide scanning range with a minimum realized gain of $5$ dBi from $-{90}^{°}$ to ${90}^{°}$ owing to this feeding approach and the peculiar placement of the array elements on a $0.15$ mm thick R-F775 bendable substrate. The generated beams at their steer direction have the minimum and maximum gain values of $6.5$ dBi and $9.7$ dBi, respectively. A low-cost PCB manufacturing technique based on soft lithography and wet etching is used. The system dimensions excluding extra connector sections are $67\times 15\times 3{\mathrm{mm}}^3$. The proposed flexible design is suitable for lightweight 5G communication systems and handsets with its compact low-complexity beamforming network, and wide ${180}^{°}$ continuous covering angle.