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 degrees to 90 degrees 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 x 15 x 3 mm3. The proposed flexible design is suitable for lightweight 5G communication systems and handsets with its compact low-complexity beamforming network, and wide 180 degrees continuous covering angle.