Investigation of an octagonal AMC reflector backed wideband antenna for gain stabilization

In this paper, an AMC reflector is proposed to stabilize the gain of a wideband bowtie antenna. This reflector is composed of a $7\times 7$ array of periodic octagonal patches, loaded on the back of the antenna structure, in order to realize a steady gain over a wide impedance bandwidth. Parametric studies are conducted to identify the key design parameters that affect the antenna performances. The obtained results indicate that the proposed structure exhibits a steady gain with 2 dB variation (between 6 and 8 dB) over a wide impedance bandwidth ranging from 3.5 to 5.80 GHz (|S
11
|<-10dB), which correspond to a 49% relative bandwidth.