Improvement of Radiation Performances of Butler Matrix-Fed Antenna Array System Using 4×1 Planar Circular EBG Units

摘要

Excitation of surface waves in the microstrip patch antenna at higher frequencies degrades the overall radiation performances. To overcome this problem, electromagnetic band gap (EBG) structures can be used. In this paper, the improvement of radiation performances of a Butler matrix-fed antenna array system has been obtained by incorporating 4 x 1 planar circular EBG units in the form of metallic patches between the array elements as well as beneath the radiating patches as circular slots. Finally, symmetric gain has been obtained for all the radiated beams at 14.5 GHz.