Broadband circularly polarized slot antenna arrays using linked elliptical slots for C- and X-band applications

摘要

Compact broadband circularly polarized elliptical slot antenna arrays (CPESAAs) are devised based on 2 x 2 and 4 x 4 circularly polarized (CP) elliptical slot antennas and a sequential phase feed network. To realize the circular polarization, eight rectangular stubs are embedded in the feed structure to excite two orthogonal E vectors in 2 x 2 CPESAA configuration. Moreover, by taking four rectangular slots out from each array element, return loss and axial-ratio bandwidths are noticeably increased. The investigated simple array element has a compact size of 20 x 20 x 1 mm(3). As well, 2 x 2 CPESAA occupies a compact size of 55 x 60 x 1 mm(3), which operates within the frequency band 4.18-9.35 GHz. Thus, 76.4% of S-11 -10 dB and 51.4% of CP bandwidth (4.43-7.5 GHz) are covered. Moreover, proposed 4 x 4 CPESAA is printed on 110 x 110 x 1 mm(3) FR4 substrate and covers the frequency band of 1.15-12.98 GHz with CP at 2.95-8.82 GHz. Throughout the study, the design process of the proposed antenna arrays are presented and discussed in detail.