Compact millimeter‐wave switched‐beam antenna arrays for short range communications

The need for more data throughput is a requirement that will keep growing in future wireless standards, and during the past few years, millimeter‐wave technology has generated much excitement in the mobile and wireless communications sectors due to the large bandwidth it can offer. In this letter two different travelling‐wave, slot antenna arrays are proposed which can offer tunable switched‐beam capability at millimeter‐wave frequencies. The antenna systems are built on a single layer PCB with top‐ and bottom‐side etching for operation at 28 GHz with at least 0.7 GHz of measured impedance bandwidth. For the first design, a planar 2 × 4 slot antenna array is proposed while the second design is implemented using a 4 × 4 slot array to demonstrate improved beam directivity. A Butler matrix for simple beam switching in the far‐field is also integrated within the compact antenna structure to provide the needed phased array operation. The total size of the two proposed systems with their feed networks are 55.2 × 55 × 0.13 mm 3 and 53.7 × 61.2 × 0.13 mm 3 , respectively. These new travelling‐wave switched beam arrays can be placed within current handheld mobile devices for high bandwidth short range communications enabling 5G technologies.