A Double Fold Multibeam Antenna for 5G Applications

In this paper, a double-folded Butler matrix multi-beam antenna based on SIW structure is proposed. The new $7\times 8$ BM combines two intermediate input ports of the traditional $8\times 8$ Butler matrix into one port, which provides output signals in the same phase so that the antenna can generate a beam of line-of-sight light. BM is folded twice to form three layers to make the BM size more compact. The measured results show that the maximum gain of this antenna is 17.3dBi within 29.5~30.5 GHz. The antenna is capable of generating 7 beams, including a boresight beam, which can scan in the range of -58°to 58°. It has obvious practical value in 5G.