Application of Electromagnetic Bandgap Structures for Mutual Coupling Reduction in Microstrip Antenna Arrays

Microstrip antenna arrays became increasingly popular in modern antenna applications due to their simplicity, compact size, and ease of mass production. One of the biggest issues in antenna arrays of microstrip antennas is the strong mutual coupling between neighbouring elements, due to their spacing and surface waves propagation, that severely impacts the active impedances and antenna pattern. The present paper discusses an opportunity to mitigate this undesirable impact. As a frequency selective surface, a mushroom-like EBG is selected, designed, and analysed with emerging technology of Floquet theorem applications (Floquet ports). The mutual coupling is estimated against the size of the EBG structure. The paper presents a straightforward and computational non intensive approach to design and evaluate various EBG structures in a close-to-real application environment.