Investigation of mutual coupling effect between five-element arrays of half cylindrical DRAs

The aim of this paper is to investigate the effect of mutual coupling between five-element arrays of half cylindrical DRAs at resonance frequency of 5.9099 GHz. The design of DRAs will be investigated using powerful electromagnetic fields simulation software called CST Microwave Studio™. A single half cylindrical DRA was designed and simulated using Microwave Studio. The results were verified with the simulation result using FDTD. In Microwave Studio, to perform the field simulation it utilises finite integration method (FI-Method) with perfect boundary approximation™ (PBA). Results obtained from Microwave Studio simulation were compared with finite difference time domain (FDTD) simulation. A good agreement between the two simulated results was obtained. The performance comparisons were focussed on near and far field distribution and the bandwidth. From single cylindrical DRA, the structure was extended into five-element arrays. The result found that in TE_01δ mode, placing the DRA side by side to each other has the risk of mutual coupling and interference. It was demonstrated that the levels of mutual coupling between the DRAs are very high when they are placed with a spacing of λ/2 between each other, thus isolation between DRAs along the length of an array is low. The level of mutual coupling between them is significant in terms of return loss and E-field distribution. The level of mutual coupling becomes weaker when the DRA is further away from the excited port.