Design of an AMC plane for a unidirectional, low-profile tulip-loop antenna

The ways of converting a wide band, electrically small in size, bi-directional quasi magnetic antenna into a unidirectional one are investigated. The purpose is to develop a magnetic wall parallel to the antenna which provides low-profile unidirectional designs, without sacrificing the bandwidth too much. Initial attempts to preserve the wide bandwidth caused some problems like pattern splitting at the broadside of the antenna and this problem has been solved by introducing an aperiodic AMC. An operational bandwidth for a VSWR les 2 of 44% in the X-band is achieved. The total height of AMC and the antenna is lambda/6.2 at f_min and lambda/4 at f_max.