Wideband Design of a Short-Slot 2-Plane Coupler by the Mode Matching/FEM Hybrid Analysis Considering the Structural Symmetry

Abstract

This paper presents the mode matching (MM)/finite element method (FEM) hybrid analysis for a short-slot 2-plane coupler, and an optimization process for a wideband design based on a genetic algorithm (GA). The method of the analysis combines a fast modal analysis of the MM which reduces the computation time, with the flexibility of an FEM which can be used with an arbitrary cross-section. In the analysis, the model is reduced into the one-eighth model by using the three-dimensional structural symmetry. The computed results agree well with those by the simulation and the computation time is reduced. The bandwidth is improved by the optimization based on the GA from 2.4% to 6.9% for the 2-plane hybrid coupler and from 5.4% to 7.5% for the 2-plane cross coupler. The measured results confirm the wideband design.

Two‐plane waveguide coupler with arbitrary coupling ratios in the H‐plane and E‐plane directions

“…The detailed information of each point is stated in Figure 1c, the irregular‐shaped coupled region is expected to provide a better approach to achieve a desired performance of the two‐plane coupler than a normal rectangular waveguide or a ridged waveguide with regular notches. The design starts from a 2‐port quarter model of the two‐plane coupler with any initial irregular‐shaped coupled region, which is defined by several points, the eigenmodes within the irregular‐shaped coupled region can be analysed by 2‐D Finite Element Method, and the connection between the input or output port with the coupled region is computed by Mode‐Matching [31]. The overall performance can be synthesised by Equations ()–(), which will be selected or disused by Genetic Algorithm, to finally determine the best shape of the coupled region and physical size as well as the position of the input or output waveguide.…”

Control of Radiation Direction in an Aperture Array Excited by a Waveguide 2-Plane Hybrid Coupler

“…2. The basic structure of the waveguide 2-plane hybrid coupler is designed by mode matching/FEM hybrid analysis [18]. The design parameters in Fig.…”