PCB-Based Design of a Beamsteerable Array With High-Gain Antennas and a Rotman Lens at 28 GHz

This letter presents a low-cost single-layer printed circuit board (PCB) design of a Rotman lens and an eight-element Yagi–Uda antenna array suitable for radio frequency (RF) beamsteering at 28 GHz. The antenna array realizes 19 dBi gain due to the guiding parasitic elements of each antenna element and a shaped ground plane surrounding the array. The array radiates in a direction parallel to the PCB enabling the possibility for two-dimensional beamsteering by stacking the PCBs. Integrated with an RF switch network, the design has seven switchable beams to the directions $-\text{30}^\circ$ , $-\text{20}^\circ$ , $-\text{10}^\circ$ , 0 $^\circ$ , 10 $^\circ$ , 20 $^\circ$ , and 30 $^\circ$ . The measured realized gain is still as high as 4–10 dBi including losses of the Rotman lens and the RF switches, thanks to the high-gain antenna array design. The array works wideband across 25.5–28.5 GHz where broadside beam gains are better than 8 dBi. This is the first letter in the literature introducing an experimentally verified design of a PCB endfire antenna array at 28 GHz including all necessary components for RF beamsteering, i.e., a Rotman lens and a switch network.