A broadband circularly polarized (CP) slot antenna array fed by an asymmetric coplanar waveguide (CPW) with stepped and inverted T-shaped strips is proposed. Using four square slot antenna elements with sequential rotation oblique feed and a modified sequential-phase (SP) feeding network, broadband CP can be achieved. The measured -10 dB reflection coefficient bandwidth and 3 dB axial ratio (AR) bandwidth are 55.4% (1.63-2.88 GHz) and 58% (1.65-3 GHz), respectively. Good radiation characteristics with gain more than 6 dBic over the operating band are obtained by the proposed antenna array with a compact size of 155×155×0.8 mm3. Details of the proposed antenna array design and experimental results are presented and discussed.
"Broadband Circularly Polarized Slot Antenna Array Using a Compact Sequential-Phase Feeding Network," Progress In Electromagnetics Research C,
Vol. 47, 173-179, 2014. doi:10.2528/PIERC14011610
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