Compact Planar Beamformer Using Multiple Continuous Parallel-Plate Waveguide Delay Lenses

Abstract

A compact planar beamformer using multiple shaped continuous parallel-plate waveguide delay lenses is proposed in this letter. The original design, based on a single-shaped continuous delay lens, had demonstrated excellent scanning properties over the portion of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K_{a}$</tex-math></inline-formula> -band allocated to uplink satcom (27.5–31 GHz). However, its height, due to the transversal ridge and cavity, was limiting its use in more advanced antenna systems. A design methodology is proposed here to achieve similar focusing properties while reducing significantly the beamformer’s height. A specific design is demonstrated with a height reduced by a factor of three when compared to the original design. A reduction of the longitudinal dimension is also proposed by introducing two additional straight ridges and cavities. A prototype was manufactured and tested successfully, with RF performance similar to those of the reference design besides slightly higher insertion losses. This compact design enables to stack multiple lenses to produce two dimensional (2-D) beamforming.