Estimation of Mutual Coupling in Integrated Lens Arrays Using a Geometrical Optics-Based Technique With Bi-Directional Forward Ray-Tracing

The use of lens arrays in (sub)-millimeter sensing and communication applications will enable the development of integrated antenna front-ends with multiple independent beams as well as dynamic scanning capabilities. In applications such as MIMO communications, interferometric arrays, and Tx/Rx duplexing capabilities, a key parameter is the mutual coupling between the integrated antenna front-ends. In this work, we model such mutual coupling using a geometrical optics (GO) technique combined with bi-directional forward ray tracing. In this model, the mutual coupling is estimated by considering up to secondary reflections in lens array geometries. The proposed technique is then used to investigate the mutual coupling for low and high-density lens arrays as a function of feed locations. The accuracy of the model is also investigated in comparison to full wave simulations and measured data reaching a sufficient agreement to identify the regions within lens arrays with critical mutual coupling levels.