A novel compact electromagnetic-bandgap (EBG) structure and its applications for microwave circuits

A novel electromagnetic-bandgap (EBG) structure in a fork-like shape is investigated. This structure has an extremely compact size. A comparison has been carried out between the new structure and the conventional mushroom-like EBG structure. Simulations and experimental results have verified that the area of the fork-like structure is less than 40% of the latter. The presented structure also provides an additional degree of freedom to adjust the bandgap position, which is applied to design a novel reconfigurable multiband EBG structure. Several application examples have been demonstrated, including a double-element microstrip antenna array with low mutual coupling, notch-type antenna duplexer, and steerable array with a linearly discrete beamsteering of 20degrees in steps of 10degrees at 2.468 GHz.