Reduction of Mutual Coupling in Compact Antenna Arrays Using Element Tilting

In this paper, a uniform circular compact antenna array of five patch elements is investigated to operate at 2.44 GHz with a bandwidth of 60 MHz. The mutual coupling, which rises between the radiating elements because of the small element spacing, reduces the radiation efficiency of the compact array. Tilting of the individual patch elements along elevation is introduced to reduce this coupling and partially restore the antenna efficiency and, particularly, the efficiency of the highest-order eigenmode of the radiation pattern. However, this reduction is usually limited to a certain tilting range. It is shown also that this range is influenced by the element spacing and dimensions of the radiating elements.