New Modeling of Horn Array Antenna Radiating in Free Space with Generalized Method-Floquet Modal Analysis

This paper presents a novel and rigorous formulation for the analysis and optimization of horn antenna arrays radiating into free space. The proposed approach employs a two-stage global method. First, a single pyramidal horn antenna is modeled by combining the Method of Moments (MoM) with the Generalized Equivalent Circuit (GEC) method. The horn is decomposed as a cascade of rectangular waveguide discontinuities with gradually increasing transverse dimensions. This model enables a detailed parametric study of the horn’s profile geometry and its influence on key radiation characteristics, including directivity and gain. In the second stage, Floquet modal analysis is applied to synthesize a periodic array from the optimized horn element. This allows for an efficient investigation of mutual coupling and the impact of inter-element spacing on the near-electric-field distribution across the array aperture. The numerical results obtained with the proposed method are presented and discussed, demonstrating good agreement with fundamental expectations and verifying the enforcement of electromagnetic boundary conditions. The formulation provides a computationally efficient and accurate tool for the design of high-performance horn arrays.