Wide-Angle Scanning Parallel-Plate Lens in Multilayer PCB Technology

This article presents the design of a dual-lens beamformer in multilayer printed circuit board (PCB) technology. The proposed lens is implemented in a dielectric parallel-plate waveguide (PPW), offering enhanced scanning performances along with a compact design. A combination of ray-tracing and conjugate field matching is used to design the lens and feed configuration. The concept is validated by a prototype operating in the downlink K-band allocated to satellite communications (17.3-20.2GHz). The shaped lens is machined from a stack of substrate layers, while the integrated feed system is realized using standard PCB techniques. The final structure produces nine stable beams over an angular sector of +/- 60 degrees (+/- 10 beamwidths) from a flared linear aperture of about 14 lambda . Good agreement between the simulated and experimental results is obtained. The measured return loss is better than 10dB, and port-to-port isolation is greater than 17dB over the entire frequency band. The estimated radiation efficiency of the antenna is about 75%, and maximum scan losses are in the order of 2dB.