Switched-Beam Slot Antenna over Electromagnetic Band-Gap Reflector

This paper presents the switched-beam slot antenna over the electromagnetic band-gap (EBG) reflector. This antenna is composed of two slot elements fed with phase difference and the EBG reflector, which is applied in order to realize the low profile structure. The radiation characteristics of this antenna are calculated using the FDTD method. The calculated results show that the antenna height over the EBG reflector can be reduced by 60 % compared with that over the perfect electric conductor (PEC) reflector. The equivalent radiation characteristics are obtained in both of the above two conditions at the center of the operating frequency band. It is shown that the elevation angle of the main beam varies corresponding to the operating frequency, and the variation in the case of the EBG reflector is caused by its frequencydependent reflection phase. Moreover, the radiation pattern of the fabricated antenna is measured, and the results demonstrate that the low profile design can be achieved by using the EBG reflector.