Abstract
This paper presents a systematic procedure for designing circularly polarized antenna arrays comprising of crossed-bowtie (cloverleaf) type of antenna elements. The gain is shown to improve from 6.87dB for single element to 15.84dB for the 3x3, and to 20.5dB for 5x5, with side lobe levels (SLLs) of -12.8dB and -11.5dB respectively. The insertion of a partially transmitting surface (PTS) further improves the gain to 18.6dB for 3x3 and 22.4dB for 5x5, and the SLL reduces to -20.9dB and -14.7dB respectively. The optimum height for the PTS superstrate is lambda/4 above the antenna element, to realize the best gain level and SLL performance. The realized return loss (S-11) bandwidth of the single antenna element is 38.5%, and its 3dB axial ratio (AR) bandwidth is 41.5 %. The proposed antenna array could be useful for C-band satellite communication.