Electromagnetic interconnection between microstrip lines through a thick ground plate

Understanding of electromagnetic coupling is an important area of research in the design and development of multi‐layered antenna arrays. In this paper, the spectral domain moment method (SDMM) is developed to investigate the coupling between two microstrip lines through a circular waveguide in a thick common‐ground plate. Measured data, along with the results obtained from the finite‐difference time‐domain (FDTD) method, are used to verify the solution. A parametric study illustrates the coupling behavior of the structure under investigation. It is observed that the frequency tuning and wide frequency bandwidth can be achieved by choosing the appropriate geometry, and this type of transition can be significantly affected by structural parameters.